The electrolyte directly contacts the essential parts of a lithium-ion battery,and as a result,the electrochemical properties of the electrolyte have a significant impact on the voltage platform,charge discharge capac...The electrolyte directly contacts the essential parts of a lithium-ion battery,and as a result,the electrochemical properties of the electrolyte have a significant impact on the voltage platform,charge discharge capacity,energy density,service life,and rate discharge performance.By raising the voltage at the charge/discharge plateau,the energy density of the battery is increased.However,this causes transition metal dissolution,irreversible phase changes of the cathode active material,and parasitic electrolyte oxidation reactions.This article presents an overview of these concerns to provide a clear explanation of the issues involved in the development of electrolytes for high-voltage lithium-ion batteries.Additionally,solidstate electrolytes enable various applications and will likely have an impact on the development of batteries with high energy densities.It is necessary to improve the high-voltage performance of electrolytes by creating solvents with high thermal stabilities and high voltage resistance and additives with superior film forming performance,multifunctional capabilities,and stable lithium salts.To offer suggestions for the future development of high-energy lithium-ion batteries,we conclude by offering our own opinions and insights on the current development of lithium-ion batteries.展开更多
Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challengi...Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.展开更多
Pursuing appropriate photo-active Li-ion storage materials and understanding their basic energy storage/conversion principle are pretty crucial for the rapidly developing photoassisted Li-ion batteries(PA-LIBs).Copper...Pursuing appropriate photo-active Li-ion storage materials and understanding their basic energy storage/conversion principle are pretty crucial for the rapidly developing photoassisted Li-ion batteries(PA-LIBs).Copper oxide(CuO)is one of the most popular candidates in both LIBs and photocatalysis.While CuO based PA-LIBs have never been reported yet.Herein,one-dimensional(1D)CuO nanowire arrays in situ grown on a three-dimensional(3D)copper foam support were employed as dualfunctional photoanode for both‘solar-to-electricity’and‘electricity-to-chemical’energy conversion in the PA-LIBs.It is found that light energy can be indeed stored and converted into electrical energy through the assembled CuO based PA-LIBs.Without external power source,the photo conversion efficiency of CuO based photocell reaches about 0.34%.Impressively,at a high current density of 4000 m A g^(-1),photoassisted discharge and charge specific capacity of CuO based PA-LIBs respectively receive 64.01%and 60.35%enhancement compared with the net electric charging and discharging process.Mechanism investigation reveals that photogenerated charges from CuO promote the interconversion between Cu^(2+)and Cu^(+)during the discharging/charging process,thus forcing the lithium storage reaction more completely and increasing the specific capacity of the PA-LIBs.This work can provide a general principle for the development of other high-efficient semiconductor-based PA-LIBs.展开更多
Si is considered as the promising anode materials for lithium-ion batteries(LIBs)owing to their high capacities of 4200 mAh g-1and natural abundancy.However,severe electrode pulverization and poor electronic and Li-io...Si is considered as the promising anode materials for lithium-ion batteries(LIBs)owing to their high capacities of 4200 mAh g-1and natural abundancy.However,severe electrode pulverization and poor electronic and Li-ionic conductivities hinder their practical applications.To resolve the afore-mentioned problems,we first demonstrate a cation-mixed disordered lattice and unique Li storage mechanism of single-phase ternary GaSiP_(2)compound,where the liquid metallic Ga and highly reactive P are incorporated into Si through a ball milling method.As confirmed by experimental and theoretical analyses,the introduced Ga and P enables to achieve the stronger resistance against volume variation and metallic conductivity,respectively,while the cation-mixed lattice provides the faster Li-ionic diffusion capability than those of the parent GaP and Si phases.The resulting GaSiP_(2)electrodes delivered the high specific capacity of 1615 mAh g-1and high initial Coulombic efficiency of 91%,while the graphite-modified GaSiP_(2)(GaSiP_(2)@C)achieved 83%of capacity retention after 900 cycles and high-rate capacity of 800 at 10,000 mA g-1.Furthermore,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)//Ga SiP_(2)@C full cells achieved the high specific capacity of 1049 mAh g-1after 100 cycles,paving a way for the rational design of high-performance LIB anode materials.展开更多
Modification of LiFePO4, LiMn2O4 and Li1+xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematic...Modification of LiFePO4, LiMn2O4 and Li1+xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematically. The results indicated that the mechanisms of Y doping in three cathode materials were different, so the influences on the material performance were different. The crystal structure of the three materials was not changed by Y doping. However, the crystal parameters were influenced. The crystal parameters of LiMn2O4 became smaller, and the interlayer distance of (100) crystal plane of Li1-xV3O8 was lengthened after Y doping. The grain size of Y-doped LiFePO4 became smaller and grain morphology became more regular than that of undoped LiFePO4. It indicated that Y doping had no influence on crystal particle and morphology of LiMn2O4. The morphology of Li1+xV3O8 became irregular and its size became larger with the increase of Y. For LiFePOaand Li1+xV3O8, both the initial discharge capacities and the cyclic performance were improved by Y doping. For LiMn2O4, the cyclic performance became better and the initial discharge capacities declined with increasing Y doping.展开更多
LiMn2O4 spinel cathode materials were modified with 2 wt.%Li-M-PO4(M=Co,Ni,Mn) by polyol synthesis method.The phosphate surface-modified LiMn2O4 cathode materials were physically characterized by X-ray diffraction(...LiMn2O4 spinel cathode materials were modified with 2 wt.%Li-M-PO4(M=Co,Ni,Mn) by polyol synthesis method.The phosphate surface-modified LiMn2O4 cathode materials were physically characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).The charge-discharge test showed that the cycling and rate capacities of LiMn2O4 cathode materials were significantly enhanced by stabilizing the electrode surface with phosphate.展开更多
Zeolitic imidazolate framework-67(ZIF-67) was synthesized on the surface of cellulose nanofibers(CNFs)in methonal to address the problems of unhomogeneous pore size and pore distribution of pure CNF membrane.A combina...Zeolitic imidazolate framework-67(ZIF-67) was synthesized on the surface of cellulose nanofibers(CNFs)in methonal to address the problems of unhomogeneous pore size and pore distribution of pure CNF membrane.A combination of Energy Dispersive X-Ray Spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS) and X-ray powder diffraction(XRD) patterns were used to determine the successful synthesis of ZIF-67@CNFs.The size of the ZIF-67 particles and pore size of the ZIF-67@CNF membrane were50-200 nm and 150-350 nm, respectively.The prepared ZIF-67@CNF membrane exhibited excellent thermal stability,lower thermal shrinkage and high surface wettability.The discharge capacity retention of the Li-ion batteries(LIBs) made with ZIF-67@CNF,glass fiber(GF),CNF and commercial polymer membranes after 100 th cycle at 0.5 C rate were 88.41%,86.22%,83.27%,and 81.03%,respectively.LIBs with ZIF-67@CNF membrane exhibited a better rate capability than these with other membranes.No damage of porous structure or peel-off of ZIF-67 was observed in the SEM images of ZIF-67@CNF membrane after100 th cycle.The improved cycling performance,rate capability,and good electrochemical stability implied that ZIF-67@CNFs membrane can be considered as a good alternative LIB separator.展开更多
The effect of external constraints on Li diffusion in high-capacity Li-ion battery electrodes is investigated using a coupled finite deformation theory. It is found that thinfilm electrodes on rigid substrates experie...The effect of external constraints on Li diffusion in high-capacity Li-ion battery electrodes is investigated using a coupled finite deformation theory. It is found that thinfilm electrodes on rigid substrates experience much slower diffusion rates compared with free-standing films with the same material properties and geometric dimensions. More importantly, the study reveals that mechanical driving forces tend to retard diffusion in highly-constrained thin films when lithiation-induced softening is considered, in contrast to the fact that mechanical driving forces always enhance diffusion when deformation is fully elastic. The results provide further proof that nano-particles are a better design option for nextgeneration alloy-based electrodes compared with thin films.展开更多
A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced. The cathode material of Li-ion battery was mixed with oxidizing agent Na2S2O8 in water solution, an...A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced. The cathode material of Li-ion battery was mixed with oxidizing agent Na2S2O8 in water solution, and the solution was stirred continuously to make the chemical reaction proceed sufficiently, then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained. A series of tests were conducted to verify the composition, crystal structure and electrochemical property of the delithiated cathode materials were all desirable. This method overcomes the shortcomings of battery charging preparation and chemical extraction preparation employing other oxidizing agents.展开更多
Perovskite,widely used in solar cells,has also been proven to be potential candidate for effective energy storage material.Recent progress indicates the promise of perovskite for battery applications,however,the speci...Perovskite,widely used in solar cells,has also been proven to be potential candidate for effective energy storage material.Recent progress indicates the promise of perovskite for battery applications,however,the specific capacity of the resulting lithium-ion batteries must be further increased.Here,by adjusting the dimensionality of perovskite,we fabricated high-performing one-dimensional hybrid perovskite C_(4)H_(20)N_(4)PbBr_(6) based lithium-ion batteries,with the first specific capacity as high as 1632.8 mAh g^(-1)and a stable specific capacity of 598.0 mAh g^(-1)after 50 cycles under the condition of the constant current density of 150 mA g^(-1).The stable specific capacity is 2.36 times higher than that of the three-dimensional perovskite CH_(3)NH_(3)PbBr_(3)(253.2 mAh g^(-1)),and 1.6 times higher than that of the commercialized graphite electrode(372 mAh g^(-1)).The structure difference and the associated ion diffusivity are revealed to substantially affect the specific capacity of the perovskite-based lithium-ion battery.Our study opens up new directions for the applications of hybrid perovskites in energy storage devices.展开更多
The layered LiNi0.6Co0.2-xMn0.2MgxO2 (x=0.00,0.03,0.05,0.07) cathode materials were prepared by a co-precipitation method.The properties of the Mg-doped LiNi0.6Co0.2Mn0.2O2 were investigated by X-ray diffraction (...The layered LiNi0.6Co0.2-xMn0.2MgxO2 (x=0.00,0.03,0.05,0.07) cathode materials were prepared by a co-precipitation method.The properties of the Mg-doped LiNi0.6Co0.2Mn0.2O2 were investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM),and electrochemical measurements.XRD studies showed that the Mg-doped LiNi0.6Co0.2Mn0.2O2 had the same layered structure as the undoped LiNi0.6Co0.2Mn0.2O2.The SEM images exhibited that the particle size of Mg-doped LiNi0.6Co0.2Mn0.2O2 was finer than that of the undoped LiNi0.6Co0.2 Mn0.2O2 and that the smallest particle size is only about 1μm.The Mg-doped LiNi0.6Co0.2Mn0.2O2 samples were investigated on the Li extraction/insertion performances through charge/discharge,cyclic voltammogram (CV),and electrochemical impedance spectra(EIS).The optimal doping content of Mg was that x= 0.03 in the LiNi0.6Co0.2-xMn0.2MgxO2 samples to achieve high discharge capacity and good cyclic stability.The electrode reaction reversibility and electronic conductivity was enhanced,and the charge transfer resistance was decreased through Mg-doping.The improved electrochemical performances of the Mg-doped LiNi0.6Co0.2Mn0.2O2 cathode materials are attributed to the addition of Mg 2+ ion by stabilizing the layer structure.展开更多
Mesoporous LiFePO4/C composites containing 80 wt% of highly dispersed LiFePO4 nanoparticles(4-6 nm) were fabricated using bimodal mesoporous carbon(BMC) as continuous conductive networks. The unique pore structure of ...Mesoporous LiFePO4/C composites containing 80 wt% of highly dispersed LiFePO4 nanoparticles(4-6 nm) were fabricated using bimodal mesoporous carbon(BMC) as continuous conductive networks. The unique pore structure of BMC not only promises good particle connectivity for LiFePO4, but also acts as a rigid nano-confinement support that controls the particle size. Furthermore, the capacities were investigated respectively based on the weight of LiFePO4 and the whole composite. When calculated based on the weight of the whole composite, it is 120 mAh·g-1at 0.1 C of the high loading electrode and 42 mAh·g-1at 10 C of the low loading electrode. The electrochemical performance shows that high LiFePO4 loading benefits large tap density and contributes to the energy storage at low rates, while the electrode with low content of LiFePO4 displays superior high rate performance, which can mainly be due to the small particle size, good dispersion and high utilization of the active material, thus leading to a fast ion and electron diffusion.展开更多
In this research, an innovative cylindrical automatic battery core oven was designed to avoid the structural deformation that frequently occurs in traditional ovens. The oven could be automatically connected with the ...In this research, an innovative cylindrical automatic battery core oven was designed to avoid the structural deformation that frequently occurs in traditional ovens. The oven could be automatically connected with the electrolyte injection process after baking, achieving improvement in a battery's baking consistency. This contributed to the feasibility of studying the internal heat conduction process of batch battery cores during actual baking processes. A mathematical model of a certain plate battery cell during the baking process was established. The simulation results of the temperature change inside the battery core during the baking process were consistent with the calculation results of the mathematical model. The temperature distribution at each point inside the battery core could be fitted through the thermal conductivity at different temperatures and the temperature distribution between the layers of the battery core.Finally, based on the thermodynamic balance energy conservation method, the relationship between the temperature change inside the battery core and the entire baking process was established. A feasible algorithm for studying the thermal conduction of complex material and internal structure objects in the baking process was obtained.展开更多
A new mesoporous carbon-tin (MC-Sn) nanocomposite has been successfully prepared via a two-step method. From the transmission electron microscopy (TEM) observations, the tin nanoparticles were decorated on the as-...A new mesoporous carbon-tin (MC-Sn) nanocomposite has been successfully prepared via a two-step method. From the transmission electron microscopy (TEM) observations, the tin nanoparticles were decorated on the as-prepared mesoporous carbons. The mesoprous structure of the carbon can effectively buffer the volume changes during the Li-Sn alloying and de-alloying cycles. The as-prepared MC/Sn nanocomposite electrodes exhibited extremely good cycling stability, with the specific capacity of Sn in the composite electrode calculated to be 959.7 mAh-g-1, which amounts to an impressive 90.9% of the theoretical value (990 mAh-g-1). The reversible capacity after 200 cycles is 96.1% of the first cycle reversible capacity, i.e., the capacity fade rate is only 0.0195% per cycle, which is even better than that of commercial graphite-based anodes.展开更多
In the search for improved materials for rechargeable lithium batteries, LiFePO4 offers interesting possibilities because of its low raw materials cost, environmental friendliness and safety. The main drawback with us...In the search for improved materials for rechargeable lithium batteries, LiFePO4 offers interesting possibilities because of its low raw materials cost, environmental friendliness and safety. The main drawback with using the material is its poor electronic conductivity and this limitation has to be overcome. Here Al-doped LiFePO4/C composite cathode materials were prepared by a polymer-network synthesis technique. Testing of X-ray diffraction, charge-discharge, and cyclic voltammetry were carried out for its performance. Results show that Al-doped LiFePO4/C composite cathode materials have a high initial capacity, good cycle stability and excellent low temperature performance. The electrical conductivity of LiFePO4 material can be obviously improved by doping Al. The better electrochemical performances of Al-doped LiFePO4/C composite cathode materials have a connection with its conductivity.展开更多
On basis of traditional battery performance model, paper analyzed the advantage and disadvantage of SOC estimation methods, introduced Adaptive Neuro-Fuzzy Inference Systems which integrated artificial neural network ...On basis of traditional battery performance model, paper analyzed the advantage and disadvantage of SOC estimation methods, introduced Adaptive Neuro-Fuzzy Inference Systems which integrated artificial neural network and fuzzy logic have predicted SOC of battery. It’s a battery residual capacity model with more generalization ability, adaptability and high precision. By analyzing the battery charge and discharge process, the key parameters of SOC are determined and the experimental model is modified in MATLAB platform.Experimental results show that the difference of SOC prediction and actual SOC is below 3%.The model can reflect the characteristics curve of the battery. SOC estimation algorithm can meet the requirements for precision. The results have a high practical value.展开更多
FeSO_(4) has the characteristics of low cost and theoretical high energy density(799 W·h·kg^(-1) with a two-electron reaction),which can meet the demand for next-generation lithium-ion batteries.Herein,FeSO_...FeSO_(4) has the characteristics of low cost and theoretical high energy density(799 W·h·kg^(-1) with a two-electron reaction),which can meet the demand for next-generation lithium-ion batteries.Herein,FeSO_(4) as a novel highperformance conversion-reaction type cathode is investigated.We use dopamine as a carbon coating source to increase its electronic conductivity.FeSO_(4)@C demonstrates a high reversible specific capacity(512 mA·h·g^(-1))and a superior cycling performance(482 mA·h·g^(-1) after 250 cycles).In addition,we further study its reaction mechanism.The FeSO_(4) is converted to Fe and Li2SO_(4) during lithium ion insertion and the Fe-Li_(2)SO_(4) grain boundaries further store additional lithium ions.Our findings are valuable in exploring other new conversion-type lithium ion battery cathodes.展开更多
Mg3(PO4)2-coated Li1.05Ni1/3Mn1/33Co1/3O2 cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and thermal stability were characterized by scanning e...Mg3(PO4)2-coated Li1.05Ni1/3Mn1/33Co1/3O2 cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and thermal stability were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), charge/discharge cycling and differential scanning calorimeter (DSC). SEM analysis shows that Mg3(PO4)2-coating changes the morphologies of their particles and increases the grains size. XRD and CV results show that Mg3(PO4)2-coating powder is homogeneous and has better layered structure than the bare one. Mg3(PO4)2-coating improved high rate discharge capacity and cycle-life performance. The reason why the cycling performance of Mg3(PO4)2-coated sample at 55 ℃ was better than that of room temperature was the increasing of lithium-ion diffusion rate and charge transfer rate with temperature rising. Mg3(PO4)2-coating improved the cathode thermal stability, and the result was consistent with thermal abuse tests using Li-ion cells: the Mg3(PO4)2 coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode did not exhibit thermal runaway with smoke and explosion, in contrast to the cells containing the bare Li1.05Ni1/3Mn1/3Co1/3O2.展开更多
A polymer electrolyte based on poly(vinylidene) fluoride-hexafluoropropylene was prepared by evaporating the solvent of dimethyl formamide, and non-woven fabric was used to reinforce the mechanical strength of polymer...A polymer electrolyte based on poly(vinylidene) fluoride-hexafluoropropylene was prepared by evaporating the solvent of dimethyl formamide, and non-woven fabric was used to reinforce the mechanical strength of polymer electrolyte and maintain a good interfacial property between the polymer electrolyte and electrodes. Polymer lithium batteries were assembled by using LiCoO2 as cathode material and lithium foil as anode material. Scanning electron microscopy, alternating current impedance, linear sweep voltammetry and charge-discharge tests were used to study the properties of polymer membrane and polymer Li-ion batteries. The results show that the technics of preparing polymer electrolyte by directly evaporating solvent is simple. The polymer membrane has rich micro-porous structure on both sides and exhibits 280% uptake of electrolyte solution. The electrochemical stability window of this polymer electrolyte is about 5.5 V, and its ionic conductivity at room temperature reaches 0.151 S/m. The polymer lithium battery displays an initial discharge capacity of 138 mA·h/g and discharge plateau of about 3.9 V at 0.2 current rate. After 30 cycles, its loss of discharge capacity is only 2%. When the battery discharges at 0.5 current rate, the voltage plateau is still 3.7 V. The discharge capacities of 0.5 and 1.0 current rates are 96% and 93% of that of 0.1 current rate, respectively.展开更多
Sn/Sb based alloy anodes have attracted considerable interest as electrodes for next-generation high performance Li-ion batteries (LIBs) owing to their high theoretical capacities. And fabricate porous structure is an...Sn/Sb based alloy anodes have attracted considerable interest as electrodes for next-generation high performance Li-ion batteries (LIBs) owing to their high theoretical capacities. And fabricate porous structure is an effective way to improve materials’ cycling performance. Here, we developed nanoporous SnSb alloy ribbon (NP-SnSb) through a melt-spinning/chemical-etching process and took it as electrode of LIB directly. Being of self-supported and binder free, the NP-SnSb shows a total outperformance over its nonporous counterparts both in cycling performance and kinetic characteristic. Besides, considering the melt-spinning/chemical-etching synthetic process is high-through-put and simple, the ribbon kind of alloy anodes have strong potential application for LIBs research.展开更多
基金supported by the Shandong Provincial Natural Science Foundation,China(No.ZR2019MEM014)。
文摘The electrolyte directly contacts the essential parts of a lithium-ion battery,and as a result,the electrochemical properties of the electrolyte have a significant impact on the voltage platform,charge discharge capacity,energy density,service life,and rate discharge performance.By raising the voltage at the charge/discharge plateau,the energy density of the battery is increased.However,this causes transition metal dissolution,irreversible phase changes of the cathode active material,and parasitic electrolyte oxidation reactions.This article presents an overview of these concerns to provide a clear explanation of the issues involved in the development of electrolytes for high-voltage lithium-ion batteries.Additionally,solidstate electrolytes enable various applications and will likely have an impact on the development of batteries with high energy densities.It is necessary to improve the high-voltage performance of electrolytes by creating solvents with high thermal stabilities and high voltage resistance and additives with superior film forming performance,multifunctional capabilities,and stable lithium salts.To offer suggestions for the future development of high-energy lithium-ion batteries,we conclude by offering our own opinions and insights on the current development of lithium-ion batteries.
基金financially supported by the Scientific and Technological Plan Projects of Guangzhou City(202103040001),P.R.Chinathe Project of Science and Technology Department of Henan Province(222102240074)the Key Research Programs of Higher Education Institutions of Henan Province(24B150009)。
文摘Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.
基金supported by the Laboratory of Lingnan Modern Agriculture Project(NZ2021029)the National Natural Science Foundation of China(Nos.21802046 and 21972048)。
文摘Pursuing appropriate photo-active Li-ion storage materials and understanding their basic energy storage/conversion principle are pretty crucial for the rapidly developing photoassisted Li-ion batteries(PA-LIBs).Copper oxide(CuO)is one of the most popular candidates in both LIBs and photocatalysis.While CuO based PA-LIBs have never been reported yet.Herein,one-dimensional(1D)CuO nanowire arrays in situ grown on a three-dimensional(3D)copper foam support were employed as dualfunctional photoanode for both‘solar-to-electricity’and‘electricity-to-chemical’energy conversion in the PA-LIBs.It is found that light energy can be indeed stored and converted into electrical energy through the assembled CuO based PA-LIBs.Without external power source,the photo conversion efficiency of CuO based photocell reaches about 0.34%.Impressively,at a high current density of 4000 m A g^(-1),photoassisted discharge and charge specific capacity of CuO based PA-LIBs respectively receive 64.01%and 60.35%enhancement compared with the net electric charging and discharging process.Mechanism investigation reveals that photogenerated charges from CuO promote the interconversion between Cu^(2+)and Cu^(+)during the discharging/charging process,thus forcing the lithium storage reaction more completely and increasing the specific capacity of the PA-LIBs.This work can provide a general principle for the development of other high-efficient semiconductor-based PA-LIBs.
基金supported by National Natural Science Foundation of China(No.22178068)the Brain Pool(BP)program(No.2021H1D3A2A02045576)funded by National Research Foundation of KoreaNational Research Foundation of Korea grant funded by the Korea government(MSIT)(No.NRF-2020R1A3B2079803 and No.2021M3D1A2043791)。
文摘Si is considered as the promising anode materials for lithium-ion batteries(LIBs)owing to their high capacities of 4200 mAh g-1and natural abundancy.However,severe electrode pulverization and poor electronic and Li-ionic conductivities hinder their practical applications.To resolve the afore-mentioned problems,we first demonstrate a cation-mixed disordered lattice and unique Li storage mechanism of single-phase ternary GaSiP_(2)compound,where the liquid metallic Ga and highly reactive P are incorporated into Si through a ball milling method.As confirmed by experimental and theoretical analyses,the introduced Ga and P enables to achieve the stronger resistance against volume variation and metallic conductivity,respectively,while the cation-mixed lattice provides the faster Li-ionic diffusion capability than those of the parent GaP and Si phases.The resulting GaSiP_(2)electrodes delivered the high specific capacity of 1615 mAh g-1and high initial Coulombic efficiency of 91%,while the graphite-modified GaSiP_(2)(GaSiP_(2)@C)achieved 83%of capacity retention after 900 cycles and high-rate capacity of 800 at 10,000 mA g-1.Furthermore,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)//Ga SiP_(2)@C full cells achieved the high specific capacity of 1049 mAh g-1after 100 cycles,paving a way for the rational design of high-performance LIB anode materials.
文摘Modification of LiFePO4, LiMn2O4 and Li1+xV3O8 by doping yttrium was investigated. The influences of doping Y on structure, morphology and electrochemical performance of cathode materials were investigated systematically. The results indicated that the mechanisms of Y doping in three cathode materials were different, so the influences on the material performance were different. The crystal structure of the three materials was not changed by Y doping. However, the crystal parameters were influenced. The crystal parameters of LiMn2O4 became smaller, and the interlayer distance of (100) crystal plane of Li1-xV3O8 was lengthened after Y doping. The grain size of Y-doped LiFePO4 became smaller and grain morphology became more regular than that of undoped LiFePO4. It indicated that Y doping had no influence on crystal particle and morphology of LiMn2O4. The morphology of Li1+xV3O8 became irregular and its size became larger with the increase of Y. For LiFePOaand Li1+xV3O8, both the initial discharge capacities and the cyclic performance were improved by Y doping. For LiMn2O4, the cyclic performance became better and the initial discharge capacities declined with increasing Y doping.
基金financially supported by the National High-Tech Research and Development(863) Program of China(No.2006AA11A160)the National Natural Science Foundation of China(No.50604018)
文摘LiMn2O4 spinel cathode materials were modified with 2 wt.%Li-M-PO4(M=Co,Ni,Mn) by polyol synthesis method.The phosphate surface-modified LiMn2O4 cathode materials were physically characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).The charge-discharge test showed that the cycling and rate capacities of LiMn2O4 cathode materials were significantly enhanced by stabilizing the electrode surface with phosphate.
基金support from Louisiana Board of Regents[LEQSF(2020-23)-RD-B-02,LEQSF(2018-19)-ENH-DE-06]Key Biomass Energy Laboratory of Henan Province(190506006 and 200606004)National Institute of Forest Science(Seoul,Korea)。
文摘Zeolitic imidazolate framework-67(ZIF-67) was synthesized on the surface of cellulose nanofibers(CNFs)in methonal to address the problems of unhomogeneous pore size and pore distribution of pure CNF membrane.A combination of Energy Dispersive X-Ray Spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS) and X-ray powder diffraction(XRD) patterns were used to determine the successful synthesis of ZIF-67@CNFs.The size of the ZIF-67 particles and pore size of the ZIF-67@CNF membrane were50-200 nm and 150-350 nm, respectively.The prepared ZIF-67@CNF membrane exhibited excellent thermal stability,lower thermal shrinkage and high surface wettability.The discharge capacity retention of the Li-ion batteries(LIBs) made with ZIF-67@CNF,glass fiber(GF),CNF and commercial polymer membranes after 100 th cycle at 0.5 C rate were 88.41%,86.22%,83.27%,and 81.03%,respectively.LIBs with ZIF-67@CNF membrane exhibited a better rate capability than these with other membranes.No damage of porous structure or peel-off of ZIF-67 was observed in the SEM images of ZIF-67@CNF membrane after100 th cycle.The improved cycling performance,rate capability,and good electrochemical stability implied that ZIF-67@CNFs membrane can be considered as a good alternative LIB separator.
基金supported by the National Research Foundation of Korea through WCU(R31-2009-000-10083-0)
文摘The effect of external constraints on Li diffusion in high-capacity Li-ion battery electrodes is investigated using a coupled finite deformation theory. It is found that thinfilm electrodes on rigid substrates experience much slower diffusion rates compared with free-standing films with the same material properties and geometric dimensions. More importantly, the study reveals that mechanical driving forces tend to retard diffusion in highly-constrained thin films when lithiation-induced softening is considered, in contrast to the fact that mechanical driving forces always enhance diffusion when deformation is fully elastic. The results provide further proof that nano-particles are a better design option for nextgeneration alloy-based electrodes compared with thin films.
基金Funded by the National Natural Science Foundation of Shanxi Province(No.2008011042-2)
文摘A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced. The cathode material of Li-ion battery was mixed with oxidizing agent Na2S2O8 in water solution, and the solution was stirred continuously to make the chemical reaction proceed sufficiently, then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained. A series of tests were conducted to verify the composition, crystal structure and electrochemical property of the delithiated cathode materials were all desirable. This method overcomes the shortcomings of battery charging preparation and chemical extraction preparation employing other oxidizing agents.
基金supported by the National Key Research and Development Program of China,China(Grant No.2017YFA0206701)the National Science Foundation of China,China(Grant No.61306079)the Beijing Municipal Science and Technology Commission,China(Grant No.Z171100002017003)。
文摘Perovskite,widely used in solar cells,has also been proven to be potential candidate for effective energy storage material.Recent progress indicates the promise of perovskite for battery applications,however,the specific capacity of the resulting lithium-ion batteries must be further increased.Here,by adjusting the dimensionality of perovskite,we fabricated high-performing one-dimensional hybrid perovskite C_(4)H_(20)N_(4)PbBr_(6) based lithium-ion batteries,with the first specific capacity as high as 1632.8 mAh g^(-1)and a stable specific capacity of 598.0 mAh g^(-1)after 50 cycles under the condition of the constant current density of 150 mA g^(-1).The stable specific capacity is 2.36 times higher than that of the three-dimensional perovskite CH_(3)NH_(3)PbBr_(3)(253.2 mAh g^(-1)),and 1.6 times higher than that of the commercialized graphite electrode(372 mAh g^(-1)).The structure difference and the associated ion diffusivity are revealed to substantially affect the specific capacity of the perovskite-based lithium-ion battery.Our study opens up new directions for the applications of hybrid perovskites in energy storage devices.
基金Funded by the Scientific Research Fund of Hunan Education Department(10C0294)
文摘The layered LiNi0.6Co0.2-xMn0.2MgxO2 (x=0.00,0.03,0.05,0.07) cathode materials were prepared by a co-precipitation method.The properties of the Mg-doped LiNi0.6Co0.2Mn0.2O2 were investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM),and electrochemical measurements.XRD studies showed that the Mg-doped LiNi0.6Co0.2Mn0.2O2 had the same layered structure as the undoped LiNi0.6Co0.2Mn0.2O2.The SEM images exhibited that the particle size of Mg-doped LiNi0.6Co0.2Mn0.2O2 was finer than that of the undoped LiNi0.6Co0.2 Mn0.2O2 and that the smallest particle size is only about 1μm.The Mg-doped LiNi0.6Co0.2Mn0.2O2 samples were investigated on the Li extraction/insertion performances through charge/discharge,cyclic voltammogram (CV),and electrochemical impedance spectra(EIS).The optimal doping content of Mg was that x= 0.03 in the LiNi0.6Co0.2-xMn0.2MgxO2 samples to achieve high discharge capacity and good cyclic stability.The electrode reaction reversibility and electronic conductivity was enhanced,and the charge transfer resistance was decreased through Mg-doping.The improved electrochemical performances of the Mg-doped LiNi0.6Co0.2Mn0.2O2 cathode materials are attributed to the addition of Mg 2+ ion by stabilizing the layer structure.
基金supported by the National Natural Science Foundation of China (NSFC 21103184)the Ph.D.Programs Foundation (20100041110017) of Ministry of Education of Chinathe Fundamental Research Funds for the Central Universities
文摘Mesoporous LiFePO4/C composites containing 80 wt% of highly dispersed LiFePO4 nanoparticles(4-6 nm) were fabricated using bimodal mesoporous carbon(BMC) as continuous conductive networks. The unique pore structure of BMC not only promises good particle connectivity for LiFePO4, but also acts as a rigid nano-confinement support that controls the particle size. Furthermore, the capacities were investigated respectively based on the weight of LiFePO4 and the whole composite. When calculated based on the weight of the whole composite, it is 120 mAh·g-1at 0.1 C of the high loading electrode and 42 mAh·g-1at 10 C of the low loading electrode. The electrochemical performance shows that high LiFePO4 loading benefits large tap density and contributes to the energy storage at low rates, while the electrode with low content of LiFePO4 displays superior high rate performance, which can mainly be due to the small particle size, good dispersion and high utilization of the active material, thus leading to a fast ion and electron diffusion.
基金supported by Tianjin Science and Technology Support Project of China(Grant 14JCTPJC00532)
文摘In this research, an innovative cylindrical automatic battery core oven was designed to avoid the structural deformation that frequently occurs in traditional ovens. The oven could be automatically connected with the electrolyte injection process after baking, achieving improvement in a battery's baking consistency. This contributed to the feasibility of studying the internal heat conduction process of batch battery cores during actual baking processes. A mathematical model of a certain plate battery cell during the baking process was established. The simulation results of the temperature change inside the battery core during the baking process were consistent with the calculation results of the mathematical model. The temperature distribution at each point inside the battery core could be fitted through the thermal conductivity at different temperatures and the temperature distribution between the layers of the battery core.Finally, based on the thermodynamic balance energy conservation method, the relationship between the temperature change inside the battery core and the entire baking process was established. A feasible algorithm for studying the thermal conduction of complex material and internal structure objects in the baking process was obtained.
基金the Australian Research Council(ARC)through ARC Centre of Excellence funding(CE0561616).
文摘A new mesoporous carbon-tin (MC-Sn) nanocomposite has been successfully prepared via a two-step method. From the transmission electron microscopy (TEM) observations, the tin nanoparticles were decorated on the as-prepared mesoporous carbons. The mesoprous structure of the carbon can effectively buffer the volume changes during the Li-Sn alloying and de-alloying cycles. The as-prepared MC/Sn nanocomposite electrodes exhibited extremely good cycling stability, with the specific capacity of Sn in the composite electrode calculated to be 959.7 mAh-g-1, which amounts to an impressive 90.9% of the theoretical value (990 mAh-g-1). The reversible capacity after 200 cycles is 96.1% of the first cycle reversible capacity, i.e., the capacity fade rate is only 0.0195% per cycle, which is even better than that of commercial graphite-based anodes.
基金This work was financially supported by the Middle Age and Youth Backbone Teacher Project (2004) of Henan Province, China.
文摘In the search for improved materials for rechargeable lithium batteries, LiFePO4 offers interesting possibilities because of its low raw materials cost, environmental friendliness and safety. The main drawback with using the material is its poor electronic conductivity and this limitation has to be overcome. Here Al-doped LiFePO4/C composite cathode materials were prepared by a polymer-network synthesis technique. Testing of X-ray diffraction, charge-discharge, and cyclic voltammetry were carried out for its performance. Results show that Al-doped LiFePO4/C composite cathode materials have a high initial capacity, good cycle stability and excellent low temperature performance. The electrical conductivity of LiFePO4 material can be obviously improved by doping Al. The better electrochemical performances of Al-doped LiFePO4/C composite cathode materials have a connection with its conductivity.
文摘On basis of traditional battery performance model, paper analyzed the advantage and disadvantage of SOC estimation methods, introduced Adaptive Neuro-Fuzzy Inference Systems which integrated artificial neural network and fuzzy logic have predicted SOC of battery. It’s a battery residual capacity model with more generalization ability, adaptability and high precision. By analyzing the battery charge and discharge process, the key parameters of SOC are determined and the experimental model is modified in MATLAB platform.Experimental results show that the difference of SOC prediction and actual SOC is below 3%.The model can reflect the characteristics curve of the battery. SOC estimation algorithm can meet the requirements for precision. The results have a high practical value.
基金Supported by the Fundamental Research Funds for the Central Universities,China(Grant No.ZYGX2019Z008)the National Natural Science Foundation of China(Grant No.52072061)。
文摘FeSO_(4) has the characteristics of low cost and theoretical high energy density(799 W·h·kg^(-1) with a two-electron reaction),which can meet the demand for next-generation lithium-ion batteries.Herein,FeSO_(4) as a novel highperformance conversion-reaction type cathode is investigated.We use dopamine as a carbon coating source to increase its electronic conductivity.FeSO_(4)@C demonstrates a high reversible specific capacity(512 mA·h·g^(-1))and a superior cycling performance(482 mA·h·g^(-1) after 250 cycles).In addition,we further study its reaction mechanism.The FeSO_(4) is converted to Fe and Li2SO_(4) during lithium ion insertion and the Fe-Li_(2)SO_(4) grain boundaries further store additional lithium ions.Our findings are valuable in exploring other new conversion-type lithium ion battery cathodes.
基金Funded by the National Natural Science Foundation of China (No. 20273047)
文摘Mg3(PO4)2-coated Li1.05Ni1/3Mn1/33Co1/3O2 cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and thermal stability were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), charge/discharge cycling and differential scanning calorimeter (DSC). SEM analysis shows that Mg3(PO4)2-coating changes the morphologies of their particles and increases the grains size. XRD and CV results show that Mg3(PO4)2-coating powder is homogeneous and has better layered structure than the bare one. Mg3(PO4)2-coating improved high rate discharge capacity and cycle-life performance. The reason why the cycling performance of Mg3(PO4)2-coated sample at 55 ℃ was better than that of room temperature was the increasing of lithium-ion diffusion rate and charge transfer rate with temperature rising. Mg3(PO4)2-coating improved the cathode thermal stability, and the result was consistent with thermal abuse tests using Li-ion cells: the Mg3(PO4)2 coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode did not exhibit thermal runaway with smoke and explosion, in contrast to the cells containing the bare Li1.05Ni1/3Mn1/3Co1/3O2.
基金Project (2003AA32X010) supported by the National High Technology Research and Development Program of China
文摘A polymer electrolyte based on poly(vinylidene) fluoride-hexafluoropropylene was prepared by evaporating the solvent of dimethyl formamide, and non-woven fabric was used to reinforce the mechanical strength of polymer electrolyte and maintain a good interfacial property between the polymer electrolyte and electrodes. Polymer lithium batteries were assembled by using LiCoO2 as cathode material and lithium foil as anode material. Scanning electron microscopy, alternating current impedance, linear sweep voltammetry and charge-discharge tests were used to study the properties of polymer membrane and polymer Li-ion batteries. The results show that the technics of preparing polymer electrolyte by directly evaporating solvent is simple. The polymer membrane has rich micro-porous structure on both sides and exhibits 280% uptake of electrolyte solution. The electrochemical stability window of this polymer electrolyte is about 5.5 V, and its ionic conductivity at room temperature reaches 0.151 S/m. The polymer lithium battery displays an initial discharge capacity of 138 mA·h/g and discharge plateau of about 3.9 V at 0.2 current rate. After 30 cycles, its loss of discharge capacity is only 2%. When the battery discharges at 0.5 current rate, the voltage plateau is still 3.7 V. The discharge capacities of 0.5 and 1.0 current rates are 96% and 93% of that of 0.1 current rate, respectively.
文摘Sn/Sb based alloy anodes have attracted considerable interest as electrodes for next-generation high performance Li-ion batteries (LIBs) owing to their high theoretical capacities. And fabricate porous structure is an effective way to improve materials’ cycling performance. Here, we developed nanoporous SnSb alloy ribbon (NP-SnSb) through a melt-spinning/chemical-etching process and took it as electrode of LIB directly. Being of self-supported and binder free, the NP-SnSb shows a total outperformance over its nonporous counterparts both in cycling performance and kinetic characteristic. Besides, considering the melt-spinning/chemical-etching synthetic process is high-through-put and simple, the ribbon kind of alloy anodes have strong potential application for LIBs research.