The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the che...The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.展开更多
A high-performance all-inorganic magnesium-lithium chloride complex(MLCC)electrolyte is synthesized by a simple room-temperature reaction of LiCl with MgCl_(2) in tetrahydrofuran(THF)solvent.Molecular dynamics simulat...A high-performance all-inorganic magnesium-lithium chloride complex(MLCC)electrolyte is synthesized by a simple room-temperature reaction of LiCl with MgCl_(2) in tetrahydrofuran(THF)solvent.Molecular dynamics simulation,density functional theory calculation,Raman spectroscopy,and nuclear magnetic resonance spectroscopy reveal that the formation of[Mg_(x)Li_(y)Cl_(2x+y)·nTHF]complex solvation structure significantly lowers the coordination number of THF in the first solvation sheath of Mg^(2+),which significantly enhances its de-solvation kinetics.The MLCC electrolyte presents a stable electrochemical window up to 3.1 V(vs Mg/Mg^(2+))and enables reversible cycling of Mg metal deposition/stripping with an outstanding Coulombic efficiency up to 99%at current densities as high as 10 mA cm^(-2).Utilizing the MLCC electrolyte,a Mg/Mo_(6)S_(8) full cell can be cycled for over 10000 cycles with a superior capacity retention of 85 mA h g^(-1) under an ultrahigh rate of 50 C(1 C=128.8 mA g^(-1)).The facile synthesis of highperformance MLCC electrolyte provides a promising solution for future practical magnesium batteries.展开更多
The rapid development and widespread application of lithium-ion batteries(LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid elect...The rapid development and widespread application of lithium-ion batteries(LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid electrolytes to severally adjust the solvation structure of lithium ions, control the components of solid electrolyte interphase, or reduce flammability. While it is highly desirable to develop low-cost multifunctional electrolyte additives integrally that address both safety and performance on LIBs, significant challenges remain. Herein, a novel phosphorus-containing organic small molecule, bis(2-methoxyethyl) methylphosphonate(BMOP), was rationally designed to serve as a fluorine-free and multifunctional additive in commercial electrolytes. This novel electrolyte additive is low-toxicity,high-efficiency, low-cost, and electrode-compatible, which shows the significant improvement to both electrochemical performance and fire safety for LIBs through regulating the electrolyte solvation structure, constructing the stable electrode-electrolyte interphase, and suppressing the electrolyte combustion. This work provides a new avenue for developing safer and high-performance LIBs.展开更多
Commercial carbonate-based electrolytes feature highly reactive activities with alkali metals,yielding low Coulombic efficiencies and poor cycle life in lithium metal batteries,which possess much higher chemical activ...Commercial carbonate-based electrolytes feature highly reactive activities with alkali metals,yielding low Coulombic efficiencies and poor cycle life in lithium metal batteries,which possess much higher chemical activity in the rising star sodium metal batteries.To be motivated,we have proposed that decreasing the solvent solvation ability in carbonate-based electrolytes stepwise could enable longterm stable cycling of high-voltage sodium metal batteries.As the solvation capacity reduces,more anions are enticed into the solvation sheath of Na^(+),resulting in the formation of the more desirable interphase layers on the surface of the anode and the cathode.The inorganic-dominated interphases allow highly efficient Na^(+)deposition/stripping processes with a lower rate of dead sodium generation,as well as maintain a stable structure of the high-voltage cathode material.Specifically,the assembled Na||Na_(3)V_(2)(PO_(4))_(2)F_(3)battery exhibits an accelerated ion diffusion kinetics and achieves a higher capacity retention of 85.9%with during the consecutive 200 cycles under the high voltage of 4.5 V.It is anticipated that the tactics we have proposed could be applicable in other secondary metal battery systems as well.展开更多
Aluminum-ion batteries(AIBs)have been highlighted as a potential alternative to lithium-ion batteries for large-scale energy storage due to the abundant reserve,light weight,low cost,and good safety of Al.However,the ...Aluminum-ion batteries(AIBs)have been highlighted as a potential alternative to lithium-ion batteries for large-scale energy storage due to the abundant reserve,light weight,low cost,and good safety of Al.However,the development of AIBs faces challenges due to the usage of AlCl_(3)-based ionic liquid electrolytes,which are expensive,corrosive,and sensitive to humidity.Here,we develop a low-cost,non-corrosive,and air-stable hydrated eutectic electrolyte composed of aluminum perchlorate nonahydrate and methylurea(MU)ligand.Through optimizing the molar ratio to achieve the unique solvation structure,the formed Al(ClO_4)_(3)·9H_(2)O/MU hydrated deep eutectic electrolyte(AMHEE)with an average coordination number of 2.4 can facilely realize stable and reversible deposition/stripping of Al.When combining with vanadium oxide nanorods positive electrode,the Al-ion full battery delivers a high discharge capacity of 320 mAh g^(-1)with good capacity retention.The unique solvation structure with a low desolvation energy of the AMHEE enables Al^(3+)insertion/extraction during charge/discharge processes,which is evidenced by in situ synchrotron radiation X-ray diffraction.This work opens a new pathway of developing low-cost,safe,environmentally friendly and high-performance electrolytes for practical and sustainable AIBs.展开更多
Zinc(Zn)metal anodes have enticed substantial curiosity for large-scale energy storage owing to inherent safety,high specific and volumetric energy capacities of Zn metal anodes.However,the aqueous electrolyte traditi...Zinc(Zn)metal anodes have enticed substantial curiosity for large-scale energy storage owing to inherent safety,high specific and volumetric energy capacities of Zn metal anodes.However,the aqueous electrolyte traditionally employed in Zn batteries suffers severe decomposition due to the narrow voltage stability window.Herein,we introduce N-methylformamide(NMF)as an organic solvent and modulate the solvation structure to obtain a stable organic/aqueous hybrid electrolyte for high-voltage Zn batteries.NMF is not only extremely stable against Zn metal anodes but also reduces the free water molecule availability by creating numerous hydrogen bonds,thereby accommodating high-voltage Zn‖LiMn_(2)O_(4)batteries.The introduction of NMF prevented hydrogen evolution reaction and promoted the creation of an Frich solid electrolyte interphase,which in turn hampered dendrite growth on Zn anodes.The Zn‖LiMn_(2)O_(4)full cells delivered a high average Coulombic efficiency of 99.7%over 400 cycles.展开更多
Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvati...Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.展开更多
Rational electrolyte design is essential for stabilizing high-energy-density lithium(Li)metal batteries but is plagued by poor understanding on the effect of electrolyte component properties on solvation structure and...Rational electrolyte design is essential for stabilizing high-energy-density lithium(Li)metal batteries but is plagued by poor understanding on the effect of electrolyte component properties on solvation structure and interfacial chemistry.Herein,regulating the solvation structure in localized high-concentration electrolytes(LHCE)by weakening the solvating power of solvents is proposed for high-performance LHCE.1,3-dimethoxypropane(DMP)solvent has relatively weak solvating power but maintains the high solubility of Li salts,thus impelling the formation of nanometric aggregates where an anion coordinates to more than two Li-ions(referred to AGG-n)in LHCE.The decomposition of AGG-n increases the Li F content in solid electrolyte interphase(SEI),further enabling uniform Li deposition.The cycle life of Li metal batteries with DMP-based LHCE is 2.1 times(386 cycles)as that of advanced ether-based LHCE under demanding conditions.Furthermore,a Li metal pouch cell of 462Wh kg^(-1)undergoes 58 cycles with the DMP-based LHCE pioneeringly.This work inspires ingenious solvating power regulation to design high-performance electrolytes for practical Li metal batteries.展开更多
Lithium metal batteries(LMBs)are considered to be one of the most promising high-energy-density battery systems.However,their practical application in carbonate electrolytes is hampered by lithium dendrite growth,resu...Lithium metal batteries(LMBs)are considered to be one of the most promising high-energy-density battery systems.However,their practical application in carbonate electrolytes is hampered by lithium dendrite growth,resulting in short cycle life.Herein,an electrolyte regulation strategy is developed to improve the cyclability of LMBs in carbonate electrolytes by introducing LiNO3 using trimethyl phosphate with a slightly higher donor number compared to NO_(3)^(-)as a solubilizer.This not only allows the formaion of Li^(+)-coordinated NO3 but also achieves the regulation of electrolyte solvation structures,leading to the formation of robust and ion-conductive solid-electrolyte interphase films with inorganic-rich inner and organic-rich outer layers on the Li metal anodes.As a result,high Coulombic efficiency of 99.1%and stable plating/stripping cycling of Li metal anode in LilCu cells were realized.Furthermore,excellent performance was also demonstrated in Li||LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2)(NCM83)full cells and Cul/NCM83 anodefree cells using high mass-loading cathodes.This work provides a simple interphase engineering strategy through regulating the electrolyte solvation structures for high-energy-density LMBs.展开更多
Aqueous zinc battery has been regarded as one of the most promising energy storage systems due to its low cost and environmental benignity.However,the safety concern on Zn anodes caused by uncontrolled Zn dendrite gro...Aqueous zinc battery has been regarded as one of the most promising energy storage systems due to its low cost and environmental benignity.However,the safety concern on Zn anodes caused by uncontrolled Zn dendrite growth in aqueous electrolyte hinders their application.Herein,sucrose with multi-hydroxyl groups has been introduced into aqueous electrolyte to modify Zn^(2+)solvation environment and create a protection layer on Zn anode,thus effectively retarding the growth of zinc dendrites.Atomistic simulations and experiments confirm that sucrose molecules can enter into the solvation sheath of Zn^(2+),and the as-formed unique solvation structure enhances the mobility of Zn^(2+).Such fast Zn^(2+)kinetics in sucrose-modified electrolyte can successfully suppress the dendrite growth.With this sucrose-modified aqueous electrolyte,Zn/Zn symmetric cells present more stable cycle performance than those using pure aqueous electrolyte;Zn/C cells also deliver an impressive higher energy density of 129.7 Wh·kg^(−1)and improved stability,suggesting a great potential application of sucrose-modified electrolytes for future Zn batteries.展开更多
Glyme-based electrolytes are of great interest for rechargeable lithium metal batteries due to their high stability,low vapor pressure,and non-flammability.Understanding the solvation structures of these electrolytes ...Glyme-based electrolytes are of great interest for rechargeable lithium metal batteries due to their high stability,low vapor pressure,and non-flammability.Understanding the solvation structures of these electrolytes at the atomic level will facilitate the design of new electrolytes with novel properties.Recently,classical molecular dynamics(CMD)and ab initio molecular dynamics(AIMD)have been applied to investigate electrolytes with complex solvation structures.On one hand,CMD may not provide reliable results as it requires complex parameterization to ensure the accuracy of the classical force field.On the other hand,the time scale of AIMD is limited by the high cost of ab initio calculations,which causes that solvation structures from AIMD simulations depend on the initial configurations.In order to solve the dilemma,machine learning method is applied to accelerate AIMD,and its time scale can be extended dramatically.In this work,we present a computational study on the solvation structures of triglyme(G3)based electrolytes by using machine learning molecular dynamics(MLMD).Firstly,we investigate the effects of density functionals on the accuracy of machine learning potential(MLP),and find that PBE-D3 shows better accuracy compared to BLYP-D3.Then,the densities of electrolytes with different concentration of LiTFSI are computed with MLMD,which shows good agreement with experiments.By analyzing the solvation structures of 1 ns MLMD trajectories,we found that Li+prefers to coordinate with a G3 and a TFSI−in equimolar electrolytes.Our work demonstrates the significance of long-time scale MLMD simulations for clarifying the chemistry of non-ideal electrolytes.展开更多
Aqueous zinc-ion batteries,due to their high power density,intrinsic safety,low cost,and environmental benign,have attracted tremendous attentions recently.However,their application is severely plagued by the inferior...Aqueous zinc-ion batteries,due to their high power density,intrinsic safety,low cost,and environmental benign,have attracted tremendous attentions recently.However,their application is severely plagued by the inferior energy density and short cycling life,which was mainly ascribed to zinc dendrites,and interfacial side reactions,narrow potential window induced by water decomposition,all of which are highly related with the Zn^(2+)solvation structures in the aqueous electrolytes.Therefore,in this review,we comprehensively summarized the recent development of strategies of regulating Zn^(2+)solvation structures,specially,the effect of zinc salts,nonaqueous co-solvents,and functional additives on the Zn^(2+)solvation structures and the corresponding electrochemical performance of aqueous zinc-ion batteries.Moreover,future perspectives focused on the challenges and possible solutions for design and commercialization of aqueous electrolytes with unique solvation structures are provided.展开更多
Aqueous Zn metal batteries(AZMBs)with intrinsic safety,high energy density and low cost have been regarded as promising electrochemical energy storage devices.However,the parasitic reaction on metallic Zn anode and th...Aqueous Zn metal batteries(AZMBs)with intrinsic safety,high energy density and low cost have been regarded as promising electrochemical energy storage devices.However,the parasitic reaction on metallic Zn anode and the incompatibility between electrode and electrolytes lead to the deterioration of electrochemical performance of AZMBs during the cycling.The critical point to achieve the stable cycling of AZMBs is to properly regulate the zinc ion solvated structure and transfer behavior between metallic Zn anode and electrolyte.In recent years,numerous achievements have been made to resolve the formation of Zn dendrite and interface incompatible issues faced by AZMBs via optimizing the sheath structure and transport capability of zinc ions at electrode-electrolyte interface.In this review,the challenges for metallic Zn anode and electrode-electrolyte interface in AZMBs including dendrite formation and interface characteristics are presented.Following the influences of different strategies involving designing advanced electrode structu re,artificial solid electrolyte interphase(SEI)on Zn anode and electrolyte engineering to regulate zinc ion solvated sheath structure and transport behavior are summarized and discussed.Finally,the perspectives for the future development of design strategies for dendrite-free Zn metal anode and long lifespan AZMBs are also given.展开更多
Rechargeable aqueous zinc(Zn) batteries hold great promise for large-scale energy storage,but their implementation is plagued by poor Zn reversibility and unsatisfactory low-temperature performance.Herein,we design a ...Rechargeable aqueous zinc(Zn) batteries hold great promise for large-scale energy storage,but their implementation is plagued by poor Zn reversibility and unsatisfactory low-temperature performance.Herein,we design a cell-nucleus structured electrolyte by introducing low-polarity 1,2-dimethoxyethane(DME) into dilute 1 M zinc trifluoromethanesulfonate(Zn(OTf)_(2)) aqueous solution,which features an OTf--rich Zn2^(+)-primary solvation sheath(PSS,inner nucleus) and the DMEmodulated Zn^(2+)-outer solvation sheath(outer layer).We find that DME additives with a low dosage do not participate in the Zn2+-PSS but reinforce the Zn-OTf-coordination,which guarantees good reaction kinetics under ultralow temperatures.Moreover,DME breaks the original H-bonding network of H2O,depressing the freezing point of electrolyte to-52.4℃.Such a cell-nucleus-solvation structure suppresses the H_(2)O-induced side reactions and forms an anion-derived solid electrolyte interphase on Zn and can be readily extended to 1,2-diethoxyethane.The as-designed electrolyte enables the Zn electrode deep cycling stability over 3500 h with a high depth-of-discharge of 51.3% and endows the Zn‖V_(2)O_(5)full battery with stable cycling over 1000 cycles at 40℃.This work would inspire the solvation structure design for low-temperature aqueous batteries.展开更多
With the booming development of lithium-ion batteries,safety has become one of the most primary focuses of current researches.Although there are various approaches to enhance the safety of lithiumion batteries,phospha...With the booming development of lithium-ion batteries,safety has become one of the most primary focuses of current researches.Although there are various approaches to enhance the safety of lithiumion batteries,phosphate-based electrolyte holds the greatest potential for practical application due to their non-flammability.Nonetheless,its compatibility issue with the graphite anode remains a significant obstacle to its widespread use.Herein,an effective method is proposed to improve the compatibility of electrolyte with graphite(Gr)anode by rationally adjusting the proportion of lithium salt and solvent components to optimize the Li^(+)solvation structure.By slightly increasing the Li^(+)/triethyl phosphate(TEP)ratio,TEP alone cannot fully occupy the inner solvation sheath and therefore less polar ethylene carbonate(EC)has to be recruited,and the solvation structure gradually changes from Li^(+)–[TEP]_(4)to Li^(+)–[TEP]_(3)[EC]with the coexistence of EC and TEP.Simultaneously,EC molecules in the Li^(+)–[TEP]_(3)[EC]could be preferentially reduced on graphite compared to the TEP molecules,resulting in the formation of a uniform and durable solid-electrolyte interphase(SEI)layer.Benefiting from the optimized phosphate-based electrolyte,the Gr|Li battery exhibits a capacity retention rate of 96.8%after stable cycling at 0.5 C for 470 cycles which shows a longer cycle life than the battery with carbonate electrolyte(cycling at 0.5 C for 450 cycles).Therefore,this work provides the guidance for designing a non-flammable phosphate-based electrolyte for high-safety and long cycling-life lithium-ion batteries.展开更多
Severe lithium(Li)dendrite growth caused by the uneven overpotential deposition is a formidable challenge for high energy density Li metal batteries(LMBs).Herein,we investigate a synergetic interfacial kinetic to regu...Severe lithium(Li)dendrite growth caused by the uneven overpotential deposition is a formidable challenge for high energy density Li metal batteries(LMBs).Herein,we investigate a synergetic interfacial kinetic to regulate Li deposition behavior and stabilize Li metal anode.Through constructing Li alloying matrix with a bi-functional silver(Ag)-Li_(3)N blended interface,fast Li^(+)conductivity and high Li affinity can be achieved simultaneously,resulting in both decreased Li nucleation and mass transfercontrolled overpotentials.Beyond these properties,a more important feature is demonstrated herein;that is,the inward diffusion depth of the Li adatoms inside of the Ag site can be restricted by the Li^(+)solvation structure in a highly coordinating environment.The latter feature can ensure the durability of the operational Ag sites,thereby elongating the Li protection ability of the Ag-Li_(3)N interface greatly.This work provides a deep insight into the synergetic effect of functional alloying structure and Li^(+)solvation mediated interfacial kinetic on Li metal protection.展开更多
The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging f...The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging for the liquid electrolyte.Herein,a novel pseudo‐oversaturated electrolyte(POSE)is prepared by introducing 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether(TTE)to adjust the coordination structure between diglyme(G2)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI).Surprisingly,although TTE shows little solubility to LiTFSI,the molar ratio between LiTFSI and G2 in the POSE can be increased to 1:1,which is much higher than that of the saturation state,1:2.8.Simulation and experimental results prove that TTE promotes closer contact of the G2 molecular with Li^(+)in the POSE.Moreover,it also participates in the formation of electrolyte/electrode interphases.The electrolyte shows outstanding compatibility with both the Li metal anode and typical high‐voltage cathodes.Li||Li symmetric cells show a long life of more than 2000 h at 1 mA cm^(−2),1 mAh cm^(−2).In the meantime,Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cell with the POSE shows a high reversible capacity of 134.8 mAh g^(−1 )after 900 cycles at 4.5 V,1 C rate.The concept of POSE can provide new insight into the Li^(+)solvation structure and in the design of advanced electrolytes for LMBs.展开更多
Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Bu...Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Butyrolactone(GBL)has emerged as a promising solvent;however,its incompatibility with graphite anode has hindered its application.This limitation necessitates a comprehensive investigation into the underlying mechanisms and potential solutions.In this study,we achieve a molecular-level understanding of the perplexing interphase formation process by employing in-situ spectroelectrochemical techniques and density function calculations.Our findings reveal that,even at high salt concentrations,GBL consistently occupies the primary Li^(+)solvation sheath,leading to extensive GBL decomposition and the formation of a high-impedance and inorganic-poor solid-electrolyte interphase(SEI)layer.Contrary to manipulating solvation structures,our research demonstrates that the utilization of filmforming additives with higher reduction potential facilitates the pre-establishment of a robust SEI film on the graphite anode.This approach effectively inhibits GBL decomposition and significantly enhances the battery's lifespan.This study provides the first reported intrinsic understanding of the unique GBLgraphite incompatibility and offers valuable insights for the development of wide-temperature and high-safety LIBs.展开更多
Ethylene carbonate(EC)is susceptible to the aggressive chemistry of nickel-rich cathodes,making it undesirable for high-voltage lithium-ion batteries(LIBs).The arbitrary elimination of EC leads to better oxidative tol...Ethylene carbonate(EC)is susceptible to the aggressive chemistry of nickel-rich cathodes,making it undesirable for high-voltage lithium-ion batteries(LIBs).The arbitrary elimination of EC leads to better oxidative tolerance but always incurs interfacial degradation and electrolyte decomposition.Herein,an EC-free electrolyte is deliberately developed based on gradient solvation by pairing solvation-protection agent(1,3,5-trifluorobenzene,F_(3)B)with propylene carbonate(PC)/methyl ethyl carbonate(EMC)formulation.F_(3)B keeps out of inner coordination shell but decomposes preferentially to construct robust interphase,inhibiting solvent decomposition and electrode corrosion.Thereby,the optimized electrolyte(1.1 M)with wide liquid range(-70–77℃)conveys decent interfacial compatibility and high-voltage stability(4.6 V for LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2),NCM622),qualifying reliable operation of practical NCM/graphite pouch cell(81.1%capacity retention over 600 cycles at 0.5 C).The solvation preservation and interface protection from F_(3)B blaze a new avenue for developing high-voltage electrolytes in next-generation LIBs.展开更多
By optimizing electrolyte formulation to inhibit the deposition of transition metal ions(TMIs) on the surface of the graphite anode is an effective way to improve the electrochemical performance of lithium-ion batteri...By optimizing electrolyte formulation to inhibit the deposition of transition metal ions(TMIs) on the surface of the graphite anode is an effective way to improve the electrochemical performance of lithium-ion batteries.At present,it is generally believed the formation of an effective interfacial film on the surface of the anode electrode is the leading factor in reducing the dissolution of TMIs and prevent TMIs from being embedded in the electrode.It ignores the influence of the solvation structures in the electrolyte system with different composition,and is not conducive to the design of the electrolyte formulation from the perspective of changing the concentration and the preferred solvent to inhibit the degradation of battery performance caused by TMIs deposition.In this work,by analyzing the special solvation structures of the high-concentra tion electrolyte,we study the main reason why high-concentration electrolyte inhibits the destructive effect of Mn(Ⅱ) on the electrochemical performance of LIBs.By combining the potentialresolved in-situ electrochemical impedance spectroscopy technology(PRIs-EIS) and density functional theory(DFT) calculation,we find that Mn(Ⅱ) mainly exists in the form of contact ions pairs(CIPs) and aggregates(AGGs) in high-concentration electrolyte.These solvation structures can reduce the destructive effect of Mn(Ⅱ) on battery performance from two aspects:on the one hand,it can rise the lowest unoccupied orbital(LUMO) value of the solvation structures of Mn(Ⅱ),thereby reducing the chance of its reduction;on the other hand,the decrease of Mn2+ions reduction can reduce the deposition of metallic manganese in the solid electrolyte interphase(SEI),thereby avoiding the continuous growth of the SEI.This study can be provided inspiration for the design of electrolytes to inhibit the destructive effect of TMls on LIBs.展开更多
基金supported by the National Natural Science Foundation of China (21875107, U1802256, and 22209204)Leading Edge Technology of Jiangsu Province (BK20220009), the Natural Science Foundation of Jiangsu Province (BK20221140)+2 种基金the China Postdoctoral Science Foundation (2022M713364)Jiangsu Specially Appointed Professors ProgramPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.
基金supported by the National Natural Science Foundation of China(NSFCU1832218)the Beijing Advanced Innovation Center for Future Chip(ICFC).
文摘A high-performance all-inorganic magnesium-lithium chloride complex(MLCC)electrolyte is synthesized by a simple room-temperature reaction of LiCl with MgCl_(2) in tetrahydrofuran(THF)solvent.Molecular dynamics simulation,density functional theory calculation,Raman spectroscopy,and nuclear magnetic resonance spectroscopy reveal that the formation of[Mg_(x)Li_(y)Cl_(2x+y)·nTHF]complex solvation structure significantly lowers the coordination number of THF in the first solvation sheath of Mg^(2+),which significantly enhances its de-solvation kinetics.The MLCC electrolyte presents a stable electrochemical window up to 3.1 V(vs Mg/Mg^(2+))and enables reversible cycling of Mg metal deposition/stripping with an outstanding Coulombic efficiency up to 99%at current densities as high as 10 mA cm^(-2).Utilizing the MLCC electrolyte,a Mg/Mo_(6)S_(8) full cell can be cycled for over 10000 cycles with a superior capacity retention of 85 mA h g^(-1) under an ultrahigh rate of 50 C(1 C=128.8 mA g^(-1)).The facile synthesis of highperformance MLCC electrolyte provides a promising solution for future practical magnesium batteries.
基金supported by the National Natural Science Foundation of China (51773134)the Sichuan Science and Technology Program (2019YFH0112)+2 种基金the Fundamental Research Funds for the Central UniversitiesInstitutional Research Fund from Sichuan University (2021SCUNL201)the 111 Project (B20001)。
文摘The rapid development and widespread application of lithium-ion batteries(LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid electrolytes to severally adjust the solvation structure of lithium ions, control the components of solid electrolyte interphase, or reduce flammability. While it is highly desirable to develop low-cost multifunctional electrolyte additives integrally that address both safety and performance on LIBs, significant challenges remain. Herein, a novel phosphorus-containing organic small molecule, bis(2-methoxyethyl) methylphosphonate(BMOP), was rationally designed to serve as a fluorine-free and multifunctional additive in commercial electrolytes. This novel electrolyte additive is low-toxicity,high-efficiency, low-cost, and electrode-compatible, which shows the significant improvement to both electrochemical performance and fire safety for LIBs through regulating the electrolyte solvation structure, constructing the stable electrode-electrolyte interphase, and suppressing the electrolyte combustion. This work provides a new avenue for developing safer and high-performance LIBs.
基金financial support from the National Natural Science Foundation of China(Grant No.22005172)the Natural Science Foundation of Sichuan Province(Grant No.2023NSFSC1124)+3 种基金the Fundamental Research Funds for the Central Universities(Grant No.YJ2021141)the Science and Technology Cooperation Special Fund of Sichuan University and Zigong City(Grant No.2022CDZG-9)the Natural Science Foundation of Shangdong Province(Grant No.ZR202211280350)the Technological Innovation Project of Tai’an City(Grant No.2022GX064)。
文摘Commercial carbonate-based electrolytes feature highly reactive activities with alkali metals,yielding low Coulombic efficiencies and poor cycle life in lithium metal batteries,which possess much higher chemical activity in the rising star sodium metal batteries.To be motivated,we have proposed that decreasing the solvent solvation ability in carbonate-based electrolytes stepwise could enable longterm stable cycling of high-voltage sodium metal batteries.As the solvation capacity reduces,more anions are enticed into the solvation sheath of Na^(+),resulting in the formation of the more desirable interphase layers on the surface of the anode and the cathode.The inorganic-dominated interphases allow highly efficient Na^(+)deposition/stripping processes with a lower rate of dead sodium generation,as well as maintain a stable structure of the high-voltage cathode material.Specifically,the assembled Na||Na_(3)V_(2)(PO_(4))_(2)F_(3)battery exhibits an accelerated ion diffusion kinetics and achieves a higher capacity retention of 85.9%with during the consecutive 200 cycles under the high voltage of 4.5 V.It is anticipated that the tactics we have proposed could be applicable in other secondary metal battery systems as well.
基金supported by the National Natural Science Foundation of China(52274302)。
文摘Aluminum-ion batteries(AIBs)have been highlighted as a potential alternative to lithium-ion batteries for large-scale energy storage due to the abundant reserve,light weight,low cost,and good safety of Al.However,the development of AIBs faces challenges due to the usage of AlCl_(3)-based ionic liquid electrolytes,which are expensive,corrosive,and sensitive to humidity.Here,we develop a low-cost,non-corrosive,and air-stable hydrated eutectic electrolyte composed of aluminum perchlorate nonahydrate and methylurea(MU)ligand.Through optimizing the molar ratio to achieve the unique solvation structure,the formed Al(ClO_4)_(3)·9H_(2)O/MU hydrated deep eutectic electrolyte(AMHEE)with an average coordination number of 2.4 can facilely realize stable and reversible deposition/stripping of Al.When combining with vanadium oxide nanorods positive electrode,the Al-ion full battery delivers a high discharge capacity of 320 mAh g^(-1)with good capacity retention.The unique solvation structure with a low desolvation energy of the AMHEE enables Al^(3+)insertion/extraction during charge/discharge processes,which is evidenced by in situ synchrotron radiation X-ray diffraction.This work opens a new pathway of developing low-cost,safe,environmentally friendly and high-performance electrolytes for practical and sustainable AIBs.
基金financial support from the Australian Research Council(ARC)through the ARC Discovery projects(DP200101249,DP210101389,DP230101579)ARC Future Fel owship(FT220100561)+1 种基金ARC Linkage project(LP200200926)ARC Industry Transformation Research Hub(IH180100020)
文摘Zinc(Zn)metal anodes have enticed substantial curiosity for large-scale energy storage owing to inherent safety,high specific and volumetric energy capacities of Zn metal anodes.However,the aqueous electrolyte traditionally employed in Zn batteries suffers severe decomposition due to the narrow voltage stability window.Herein,we introduce N-methylformamide(NMF)as an organic solvent and modulate the solvation structure to obtain a stable organic/aqueous hybrid electrolyte for high-voltage Zn batteries.NMF is not only extremely stable against Zn metal anodes but also reduces the free water molecule availability by creating numerous hydrogen bonds,thereby accommodating high-voltage Zn‖LiMn_(2)O_(4)batteries.The introduction of NMF prevented hydrogen evolution reaction and promoted the creation of an Frich solid electrolyte interphase,which in turn hampered dendrite growth on Zn anodes.The Zn‖LiMn_(2)O_(4)full cells delivered a high average Coulombic efficiency of 99.7%over 400 cycles.
基金supported by the National Natural Science Foundation of China(51962019)the Natural Science Foundation of Gansu Province(20JR5RA469)+1 种基金the Education Department of Gansu Province:"Star of Innovation"Project for Outstanding Graduate Students(2021CXZX-455)the Lanzhou University of Technology Hongliu First-class Discipline Construction Program。
文摘Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.
基金supported by National Key Research and Development Program (2021YFB2400300)the Beijing Natural Science Foundation (JQ20004)+2 种基金the National Natural Science Foundation of China (22209010 and 22109007)the Beijing Institute of Technology Research Fund Program for Young Scholarsthe Tsinghua University Initiative Scientific Research Program。
文摘Rational electrolyte design is essential for stabilizing high-energy-density lithium(Li)metal batteries but is plagued by poor understanding on the effect of electrolyte component properties on solvation structure and interfacial chemistry.Herein,regulating the solvation structure in localized high-concentration electrolytes(LHCE)by weakening the solvating power of solvents is proposed for high-performance LHCE.1,3-dimethoxypropane(DMP)solvent has relatively weak solvating power but maintains the high solubility of Li salts,thus impelling the formation of nanometric aggregates where an anion coordinates to more than two Li-ions(referred to AGG-n)in LHCE.The decomposition of AGG-n increases the Li F content in solid electrolyte interphase(SEI),further enabling uniform Li deposition.The cycle life of Li metal batteries with DMP-based LHCE is 2.1 times(386 cycles)as that of advanced ether-based LHCE under demanding conditions.Furthermore,a Li metal pouch cell of 462Wh kg^(-1)undergoes 58 cycles with the DMP-based LHCE pioneeringly.This work inspires ingenious solvating power regulation to design high-performance electrolytes for practical Li metal batteries.
基金supported by the National Key Research and Development Program of China(No.2019YFE0118800).
文摘Lithium metal batteries(LMBs)are considered to be one of the most promising high-energy-density battery systems.However,their practical application in carbonate electrolytes is hampered by lithium dendrite growth,resulting in short cycle life.Herein,an electrolyte regulation strategy is developed to improve the cyclability of LMBs in carbonate electrolytes by introducing LiNO3 using trimethyl phosphate with a slightly higher donor number compared to NO_(3)^(-)as a solubilizer.This not only allows the formaion of Li^(+)-coordinated NO3 but also achieves the regulation of electrolyte solvation structures,leading to the formation of robust and ion-conductive solid-electrolyte interphase films with inorganic-rich inner and organic-rich outer layers on the Li metal anodes.As a result,high Coulombic efficiency of 99.1%and stable plating/stripping cycling of Li metal anode in LilCu cells were realized.Furthermore,excellent performance was also demonstrated in Li||LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2)(NCM83)full cells and Cul/NCM83 anodefree cells using high mass-loading cathodes.This work provides a simple interphase engineering strategy through regulating the electrolyte solvation structures for high-energy-density LMBs.
基金support from the National Natural Science Foundation of China(Nos.22075313 and 21975281)the National Key Research and Development Program of China(No.2020YFB1312902)+3 种基金the Science and Technology Project of Jiangxi Province(No.20192BCD40017)Outstanding Youth Fund of Jiangxi Province(No.20192BCB23028)Jiangxi Double Thousand Talent Program(No.JXSQ2019101072)Science Technology Major Project of Nanchang(No.2020BI47)is acknowledged.
文摘Aqueous zinc battery has been regarded as one of the most promising energy storage systems due to its low cost and environmental benignity.However,the safety concern on Zn anodes caused by uncontrolled Zn dendrite growth in aqueous electrolyte hinders their application.Herein,sucrose with multi-hydroxyl groups has been introduced into aqueous electrolyte to modify Zn^(2+)solvation environment and create a protection layer on Zn anode,thus effectively retarding the growth of zinc dendrites.Atomistic simulations and experiments confirm that sucrose molecules can enter into the solvation sheath of Zn^(2+),and the as-formed unique solvation structure enhances the mobility of Zn^(2+).Such fast Zn^(2+)kinetics in sucrose-modified electrolyte can successfully suppress the dendrite growth.With this sucrose-modified aqueous electrolyte,Zn/Zn symmetric cells present more stable cycle performance than those using pure aqueous electrolyte;Zn/C cells also deliver an impressive higher energy density of 129.7 Wh·kg^(−1)and improved stability,suggesting a great potential application of sucrose-modified electrolytes for future Zn batteries.
基金National Natural Science Foundation of China(Nos.21991151,21991150,21861132015,22225302 and 22021001)the Fundamental Research Funds for the Central Universities(No.20720220009)Xiamen Science and Technology Plan Project(No.3502Z20203027)for financial support.
文摘Glyme-based electrolytes are of great interest for rechargeable lithium metal batteries due to their high stability,low vapor pressure,and non-flammability.Understanding the solvation structures of these electrolytes at the atomic level will facilitate the design of new electrolytes with novel properties.Recently,classical molecular dynamics(CMD)and ab initio molecular dynamics(AIMD)have been applied to investigate electrolytes with complex solvation structures.On one hand,CMD may not provide reliable results as it requires complex parameterization to ensure the accuracy of the classical force field.On the other hand,the time scale of AIMD is limited by the high cost of ab initio calculations,which causes that solvation structures from AIMD simulations depend on the initial configurations.In order to solve the dilemma,machine learning method is applied to accelerate AIMD,and its time scale can be extended dramatically.In this work,we present a computational study on the solvation structures of triglyme(G3)based electrolytes by using machine learning molecular dynamics(MLMD).Firstly,we investigate the effects of density functionals on the accuracy of machine learning potential(MLP),and find that PBE-D3 shows better accuracy compared to BLYP-D3.Then,the densities of electrolytes with different concentration of LiTFSI are computed with MLMD,which shows good agreement with experiments.By analyzing the solvation structures of 1 ns MLMD trajectories,we found that Li+prefers to coordinate with a G3 and a TFSI−in equimolar electrolytes.Our work demonstrates the significance of long-time scale MLMD simulations for clarifying the chemistry of non-ideal electrolytes.
基金supported by Natural Science Foundation of Hunan Province(2023JJ40662)National Defense Science and Technology Key Laboratory Supporting Project(WDZC20235250508)+1 种基金National Natural Science Foundation(22002186)Seed Fund of National University of Defense Technology.
文摘Aqueous zinc-ion batteries,due to their high power density,intrinsic safety,low cost,and environmental benign,have attracted tremendous attentions recently.However,their application is severely plagued by the inferior energy density and short cycling life,which was mainly ascribed to zinc dendrites,and interfacial side reactions,narrow potential window induced by water decomposition,all of which are highly related with the Zn^(2+)solvation structures in the aqueous electrolytes.Therefore,in this review,we comprehensively summarized the recent development of strategies of regulating Zn^(2+)solvation structures,specially,the effect of zinc salts,nonaqueous co-solvents,and functional additives on the Zn^(2+)solvation structures and the corresponding electrochemical performance of aqueous zinc-ion batteries.Moreover,future perspectives focused on the challenges and possible solutions for design and commercialization of aqueous electrolytes with unique solvation structures are provided.
基金supported by the National Key Research and Development Programs(2021YFB2400400)Major Science and Technology Innovation Project of Hunan Province(2020GK10102020GK1014-4)+7 种基金National Natural Science Foundation of China(32201162)the 70th general grant of China Postdoctoral Science Foundation(2021M702947)Natural Science Foundation of Henan(232300420404)Key Scientific and Technological Project of Henan Province(232102320290,232102311156)Key Research Project Plan for Higher Education Institutions in Henan Province(24A150009,23B430011)Doctor Foundation of Henan University of Engineering(D2022002)the Science and Technology Innovation Program of Hunan Province(2023RC3154)the scientific research projects of Education Department of Hunan Province(23A0188)。
文摘Aqueous Zn metal batteries(AZMBs)with intrinsic safety,high energy density and low cost have been regarded as promising electrochemical energy storage devices.However,the parasitic reaction on metallic Zn anode and the incompatibility between electrode and electrolytes lead to the deterioration of electrochemical performance of AZMBs during the cycling.The critical point to achieve the stable cycling of AZMBs is to properly regulate the zinc ion solvated structure and transfer behavior between metallic Zn anode and electrolyte.In recent years,numerous achievements have been made to resolve the formation of Zn dendrite and interface incompatible issues faced by AZMBs via optimizing the sheath structure and transport capability of zinc ions at electrode-electrolyte interface.In this review,the challenges for metallic Zn anode and electrode-electrolyte interface in AZMBs including dendrite formation and interface characteristics are presented.Following the influences of different strategies involving designing advanced electrode structu re,artificial solid electrolyte interphase(SEI)on Zn anode and electrolyte engineering to regulate zinc ion solvated sheath structure and transport behavior are summarized and discussed.Finally,the perspectives for the future development of design strategies for dendrite-free Zn metal anode and long lifespan AZMBs are also given.
基金supported by the National Natural Science Foundation of China (21925503, 21871149, 21835004, and 22075067)the Ministry of Education of China (B12015)+2 种基金Haihe Laboratory of Sustainable Chemical Transformations (CYZC202110)Hebei Natural Science Foundation (B2020201001)the Fundamental Research Funds for the Central Universities,Nankai University(020-63201046)。
文摘Rechargeable aqueous zinc(Zn) batteries hold great promise for large-scale energy storage,but their implementation is plagued by poor Zn reversibility and unsatisfactory low-temperature performance.Herein,we design a cell-nucleus structured electrolyte by introducing low-polarity 1,2-dimethoxyethane(DME) into dilute 1 M zinc trifluoromethanesulfonate(Zn(OTf)_(2)) aqueous solution,which features an OTf--rich Zn2^(+)-primary solvation sheath(PSS,inner nucleus) and the DMEmodulated Zn^(2+)-outer solvation sheath(outer layer).We find that DME additives with a low dosage do not participate in the Zn2+-PSS but reinforce the Zn-OTf-coordination,which guarantees good reaction kinetics under ultralow temperatures.Moreover,DME breaks the original H-bonding network of H2O,depressing the freezing point of electrolyte to-52.4℃.Such a cell-nucleus-solvation structure suppresses the H_(2)O-induced side reactions and forms an anion-derived solid electrolyte interphase on Zn and can be readily extended to 1,2-diethoxyethane.The as-designed electrolyte enables the Zn electrode deep cycling stability over 3500 h with a high depth-of-discharge of 51.3% and endows the Zn‖V_(2)O_(5)full battery with stable cycling over 1000 cycles at 40℃.This work would inspire the solvation structure design for low-temperature aqueous batteries.
基金the National Natural Science Foundation of China(52034011 and 52101278)the Central South University Research Programme of Advanced Interdisciplinary Studies(2023QYJC005)the Fundamental Research Funds for Central Universities of the Central South University(2022ZZTS0405)。
文摘With the booming development of lithium-ion batteries,safety has become one of the most primary focuses of current researches.Although there are various approaches to enhance the safety of lithiumion batteries,phosphate-based electrolyte holds the greatest potential for practical application due to their non-flammability.Nonetheless,its compatibility issue with the graphite anode remains a significant obstacle to its widespread use.Herein,an effective method is proposed to improve the compatibility of electrolyte with graphite(Gr)anode by rationally adjusting the proportion of lithium salt and solvent components to optimize the Li^(+)solvation structure.By slightly increasing the Li^(+)/triethyl phosphate(TEP)ratio,TEP alone cannot fully occupy the inner solvation sheath and therefore less polar ethylene carbonate(EC)has to be recruited,and the solvation structure gradually changes from Li^(+)–[TEP]_(4)to Li^(+)–[TEP]_(3)[EC]with the coexistence of EC and TEP.Simultaneously,EC molecules in the Li^(+)–[TEP]_(3)[EC]could be preferentially reduced on graphite compared to the TEP molecules,resulting in the formation of a uniform and durable solid-electrolyte interphase(SEI)layer.Benefiting from the optimized phosphate-based electrolyte,the Gr|Li battery exhibits a capacity retention rate of 96.8%after stable cycling at 0.5 C for 470 cycles which shows a longer cycle life than the battery with carbonate electrolyte(cycling at 0.5 C for 450 cycles).Therefore,this work provides the guidance for designing a non-flammable phosphate-based electrolyte for high-safety and long cycling-life lithium-ion batteries.
基金supported by the 21C Innovation Laboratory,Contemporary Amperex Technology Ltd by project No.21C-OP-202004,the Ningbo S&T Innovation 2025 Major Special Program(Grant No.2018B10061,2018B10087,2019B10044,and 2020Z101)the National Key R&D Program of China(Grant No.2018YFB0905400).
文摘Severe lithium(Li)dendrite growth caused by the uneven overpotential deposition is a formidable challenge for high energy density Li metal batteries(LMBs).Herein,we investigate a synergetic interfacial kinetic to regulate Li deposition behavior and stabilize Li metal anode.Through constructing Li alloying matrix with a bi-functional silver(Ag)-Li_(3)N blended interface,fast Li^(+)conductivity and high Li affinity can be achieved simultaneously,resulting in both decreased Li nucleation and mass transfercontrolled overpotentials.Beyond these properties,a more important feature is demonstrated herein;that is,the inward diffusion depth of the Li adatoms inside of the Ag site can be restricted by the Li^(+)solvation structure in a highly coordinating environment.The latter feature can ensure the durability of the operational Ag sites,thereby elongating the Li protection ability of the Ag-Li_(3)N interface greatly.This work provides a deep insight into the synergetic effect of functional alloying structure and Li^(+)solvation mediated interfacial kinetic on Li metal protection.
基金Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance,Grant/Award Number:22567616HNatural Science Foundation of Hebei Province of China,Grant/Award Number:B2020103028+3 种基金Science Fund for Creative Research Groups of the National Natural Science Foundation of China,Grant/Award Number:21921005National Key Research and Development Program of China,Grant/Award Number:2021YFB2400300Beijing Municipal Natural Science Foundation Project,Grant/Award Number:2222031National Natural Science Foundation of China,Grant/Award Numbers:52174281,21808228。
文摘The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging for the liquid electrolyte.Herein,a novel pseudo‐oversaturated electrolyte(POSE)is prepared by introducing 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether(TTE)to adjust the coordination structure between diglyme(G2)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI).Surprisingly,although TTE shows little solubility to LiTFSI,the molar ratio between LiTFSI and G2 in the POSE can be increased to 1:1,which is much higher than that of the saturation state,1:2.8.Simulation and experimental results prove that TTE promotes closer contact of the G2 molecular with Li^(+)in the POSE.Moreover,it also participates in the formation of electrolyte/electrode interphases.The electrolyte shows outstanding compatibility with both the Li metal anode and typical high‐voltage cathodes.Li||Li symmetric cells show a long life of more than 2000 h at 1 mA cm^(−2),1 mAh cm^(−2).In the meantime,Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cell with the POSE shows a high reversible capacity of 134.8 mAh g^(−1 )after 900 cycles at 4.5 V,1 C rate.The concept of POSE can provide new insight into the Li^(+)solvation structure and in the design of advanced electrolytes for LMBs.
基金financially supported by the National Natural Science Foundation of China(21972049,22272175)the National Key R&D Program of China(2022YFA1504002)+3 种基金the“Scientist Studio Funding”from Tianmu Lake Institute of Advanced Energy Storage Technologies Co.,Ltd.Dalian Supports High-Level Talent Innovation and Entrepreneurship Projects(2021RD14)the Dalian Institute of Chemical Physics(DICP I202213)the 21C Innovation Laboratory,Contemporary Ampere Technology Ltd.by project No.21C-OP-202208。
文摘Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Butyrolactone(GBL)has emerged as a promising solvent;however,its incompatibility with graphite anode has hindered its application.This limitation necessitates a comprehensive investigation into the underlying mechanisms and potential solutions.In this study,we achieve a molecular-level understanding of the perplexing interphase formation process by employing in-situ spectroelectrochemical techniques and density function calculations.Our findings reveal that,even at high salt concentrations,GBL consistently occupies the primary Li^(+)solvation sheath,leading to extensive GBL decomposition and the formation of a high-impedance and inorganic-poor solid-electrolyte interphase(SEI)layer.Contrary to manipulating solvation structures,our research demonstrates that the utilization of filmforming additives with higher reduction potential facilitates the pre-establishment of a robust SEI film on the graphite anode.This approach effectively inhibits GBL decomposition and significantly enhances the battery's lifespan.This study provides the first reported intrinsic understanding of the unique GBLgraphite incompatibility and offers valuable insights for the development of wide-temperature and high-safety LIBs.
基金supported by the National Key Research and Development Program of China(No.2022YFB2404800)。
文摘Ethylene carbonate(EC)is susceptible to the aggressive chemistry of nickel-rich cathodes,making it undesirable for high-voltage lithium-ion batteries(LIBs).The arbitrary elimination of EC leads to better oxidative tolerance but always incurs interfacial degradation and electrolyte decomposition.Herein,an EC-free electrolyte is deliberately developed based on gradient solvation by pairing solvation-protection agent(1,3,5-trifluorobenzene,F_(3)B)with propylene carbonate(PC)/methyl ethyl carbonate(EMC)formulation.F_(3)B keeps out of inner coordination shell but decomposes preferentially to construct robust interphase,inhibiting solvent decomposition and electrode corrosion.Thereby,the optimized electrolyte(1.1 M)with wide liquid range(-70–77℃)conveys decent interfacial compatibility and high-voltage stability(4.6 V for LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2),NCM622),qualifying reliable operation of practical NCM/graphite pouch cell(81.1%capacity retention over 600 cycles at 0.5 C).The solvation preservation and interface protection from F_(3)B blaze a new avenue for developing high-voltage electrolytes in next-generation LIBs.
基金supported by the Natural Science Foundation of Gansu Province for Youths(21JR7RA254)the Gansu Provincial Department of Education: Innovation Fund Project(2022A-029)+1 种基金the Major Special Fund of Gansu Province(21ZD4GA031)the Lanzhou University of Technology Hongliu First-class Discipline Construction Program and Gansu Province Central Government Guided Local Science and Technology Development Fund ProjectIndustrialization of Automotive Low-Temperature Lithium-ion Battery Manufacturing Technology Achievements。
文摘By optimizing electrolyte formulation to inhibit the deposition of transition metal ions(TMIs) on the surface of the graphite anode is an effective way to improve the electrochemical performance of lithium-ion batteries.At present,it is generally believed the formation of an effective interfacial film on the surface of the anode electrode is the leading factor in reducing the dissolution of TMIs and prevent TMIs from being embedded in the electrode.It ignores the influence of the solvation structures in the electrolyte system with different composition,and is not conducive to the design of the electrolyte formulation from the perspective of changing the concentration and the preferred solvent to inhibit the degradation of battery performance caused by TMIs deposition.In this work,by analyzing the special solvation structures of the high-concentra tion electrolyte,we study the main reason why high-concentration electrolyte inhibits the destructive effect of Mn(Ⅱ) on the electrochemical performance of LIBs.By combining the potentialresolved in-situ electrochemical impedance spectroscopy technology(PRIs-EIS) and density functional theory(DFT) calculation,we find that Mn(Ⅱ) mainly exists in the form of contact ions pairs(CIPs) and aggregates(AGGs) in high-concentration electrolyte.These solvation structures can reduce the destructive effect of Mn(Ⅱ) on battery performance from two aspects:on the one hand,it can rise the lowest unoccupied orbital(LUMO) value of the solvation structures of Mn(Ⅱ),thereby reducing the chance of its reduction;on the other hand,the decrease of Mn2+ions reduction can reduce the deposition of metallic manganese in the solid electrolyte interphase(SEI),thereby avoiding the continuous growth of the SEI.This study can be provided inspiration for the design of electrolytes to inhibit the destructive effect of TMls on LIBs.