Lithium (Li) metal with an ultrahigh specific theoretical capacity and the lowest reduction potential is strongly considered as a promising anode for high-energy-density batteries. However, uncontrolled lithium dendri...Lithium (Li) metal with an ultrahigh specific theoretical capacity and the lowest reduction potential is strongly considered as a promising anode for high-energy-density batteries. However, uncontrolled lithium dendrites and infinite volume change during repeated plating/stripping cycles hinder its practical applications immensely. Herein, a house-like Li anode (housed Li) was designed to circumvent the above issues. The house matrix was composed of carbon fiber matrix and affords a stable structure to relieve the volume change. An artificial solid electrolyte layer was formed on composite Li metal, just like the roof of a house, which facilitates uniform Li ions diffusion and serves as a physical barrier against electrolyte corrosion. With the combination of solid electrolyte layer and matrix in the composite Li metal anode, both dendrite growth and volume expansion are remarkably inhibited. The housed Li|LiFePO4 batteries exhibited over 95% capacity retention after 500 cycles at 1.0 C in coin cell and 85% capacity retention after 80 cycles at 0.5 C in pouch cell. The rationally combination of solid electrolyte layer protection and housed framework in one Li metal anode sheds fresh insights on the design principle of a safe and long-lifespan Li metal anode for Li metal batteries.展开更多
As an efficient and environmental friendly energy storage system, lithium battery has been integrated into daily mobile life [1].Lithium batteries are becoming indispensable to all types of electronic products such as...As an efficient and environmental friendly energy storage system, lithium battery has been integrated into daily mobile life [1].Lithium batteries are becoming indispensable to all types of electronic products such as laptop computers, mobile phones, digital cameras [2]. A typical lithium battery consists of positive electrode(cathode), negative electrode(anode), electrolyte and other inactive materials(binder, conductive agent, separator) [3].展开更多
Solid electrolyte interphase(SEI)has been widely recognized as the most important and the least understood component in lithium batteries.Considering the intrinsic instability in both chemical and mechanical,the failu...Solid electrolyte interphase(SEI)has been widely recognized as the most important and the least understood component in lithium batteries.Considering the intrinsic instability in both chemical and mechanical,the failure of SEI is inevitable and strongly associated with the performance decay of practical working batteries.In this Review,the failure mechanisms and the corresponding regulation strategies of SEI are focused.Firstly,the fundamental properties of SEI,including the formation principles,and the typical composition and structures are briefly introduced.Moreover,the common SEI failure modes involving thermal failure,chemical failure,and mechanical failure are classified and discussed,respectively.Beyond that,the regulation strategies of SEI with respect to different failure modes are further concluded.Finally,the future endeavor in further disclosing the mysteries of SEI is prospected.展开更多
Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactiv...Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactive lithium metal result in the severe safety risks and the short lifespan for highenergy-density rechargeable batteries.Here,we demonstrate a hydrophobic and ionically conductive ethylene-vinyl acetate(EVA)copolymer layer can not only endow lithium metal anodes with an air-stable and anti-water surface,but also efficiently suppress the lithium-dendrites growth during the electrochemical cycling process.Therefore,the introduction of the EVA copolymer as a bifunctional protection layer simultaneously improves the anti-water/air performance and electrochemical cycling stability of lithium metal anode.展开更多
Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase(SEI)covered on the graphite anode determines the service life of a battery.The formation method and the formation temperature ...Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase(SEI)covered on the graphite anode determines the service life of a battery.The formation method and the formation temperature at initial cycle of a battery determine the feature of the SEI.Herein,we investigate the gap of formation behavior in both a half cell(graphite matches with lithium anode)and a full cell(graphite matches with NCM,short for LiNixCoyMn1-x-yO2)at different temperatures.We conclude that high temperature causes severe side reactions and low temperature will result in low ionic conductive SEI layer,the interface formed at room temperature owns the best ionic conductivity and stability.展开更多
Lithium (Li) metal attributes to the promising anode but endures the low Columbic efficiency (CE) and safety issues from the inactive Li accumulation. The metallic Li which is isolated from the lithium anode (named de...Lithium (Li) metal attributes to the promising anode but endures the low Columbic efficiency (CE) and safety issues from the inactive Li accumulation. The metallic Li which is isolated from the lithium anode (named dead Li^(0)) consists the major component of the inactive Li. We systematically and meticulously investigated the formation and evaluation of dead Li^(0) during stripping process from electron transfer, the oxidation of Li^(0) to Li^(+) and the diffusion of Li^(+) through solid electrolyte interphase (SEI). The above-mentioned processes were regulated by adjusting the contact sites of electron channels, the dynamic rate of conversion from Li^(0) to Li^(+), and the structure as well as components of SEI. The design principles for achieving less dead Li^(0) and higher CE are proposed as a proof of concept in lithium metal batteries. This new insight sheds a comprehensive light on dead Li^(0) formation and guides the next-generation safe batteries for future application.展开更多
Lithium plating in working batteries has attracted wide attention in the exploration of safe energy storage. Establishing an effective and rapid early-warning method is strongly considered but quite challenging since ...Lithium plating in working batteries has attracted wide attention in the exploration of safe energy storage. Establishing an effective and rapid early-warning method is strongly considered but quite challenging since lithium plating behavior is determined by diverse factors. In this contribution, we present a non-destructive electrochemical detection method based on transient state analysis and threeelectrode cell configuration. Through dividing the iR drop value by the current density, the as-obtained impedance quantity(R_(i)) can serve as a descriptor to describe the change of electrochemical reaction impedance on the graphite anode. The onset of lithium plating can be identified from the sharp drop of R_(i). Once the dendritic plated lithium occurs, the extra electrochemical reactions at the lithium interfaces leads to growing active area and reduced surface resistance of the anode. We proposed a protocol to operate the batteries under the limited capacity, which renders the cell with 98.2% capacity retention after 1000 cycles without lithium plating. The early-warning method has also been validated in in-situ optical microscopy batteries and practical pouch cells, providing a general but effective method for online lithium plating detection towards safe batteries.展开更多
Lithium-sulfur battery(LSB) has high energy density but is limited by the polysulfides shuttle and dendrite growth during cycling. Herein, a free-standing cellulose nanofiber(CNF) separator is designed and fabricated ...Lithium-sulfur battery(LSB) has high energy density but is limited by the polysulfides shuttle and dendrite growth during cycling. Herein, a free-standing cellulose nanofiber(CNF) separator is designed and fabricated in isopropanol/water suspension through vacuum filtration progress. CNFs with abundant polar oxygen-containing functional groups can chemically immobilize the polysulfides, and suppress the formation of the dendrites by controlling the surface morphology of the SEI on lithium metal in LSB. The isopropanol content in a suspension can fine-tune the pore structure of the membrane to achieve optimal electrochemical performance. The prepared separator displays integrated advantages of an ultrathin thickness(19 μm), lightweight(0.87 mg cm^(-2)), extremely high porosity(98.05%), and decent electrolyte affinity. As a result, the discharge capacity of the LSB with CNF separator at the first and 100 th cycle is 1.4 and 1.3 times that of PP separator, respectively. Our research provides an environmentalfriendly and facile strategy for the preparation of multifunctional separators for LSBs.展开更多
Magnesium–sulfur batteries promise high volumetric energy density,enhanced safety,and low cost for electrochemical energy storage.The current obstacles to practical applications of reliable magnesium–sulfur batterie...Magnesium–sulfur batteries promise high volumetric energy density,enhanced safety,and low cost for electrochemical energy storage.The current obstacles to practical applications of reliable magnesium–sulfur batteries are finding electrolytes that can meet a multitude of rigorous requirements along with efficient sulfur cathodes and magnesium anodes.This review highlights recent advances in designing better electrolytes,cathodes,and anodes.A suitable electrolyte for magnesium-sulfur batteries should allow to reversibly electroplate/strip divalent magnesium ions and should be compatible with the sulfur cathode and the other cell’s components.展开更多
Fast charging capability of lithium-ion batteries is in urgent need for widespread economic success of electric vehicles. However, the application of the fast charging technology often leads to the inevitable lithium ...Fast charging capability of lithium-ion batteries is in urgent need for widespread economic success of electric vehicles. However, the application of the fast charging technology often leads to the inevitable lithium plating on the graphite anode, which is one of the main culprits that endanger battery safety and shorten battery lifespan. The in-depth understanding of the initiation of lithium metal nucleation and the following plating behavior is a key to the development of fast charging cells. Herein, we investigate the overlooked effect of the non-uniform distribution of electrolyte on lithium plating during fast charging. Prior lithium plating occurs on the saturated lithium-graphite compounds in the anode region with sufficient electrolyte since the lithium-ion transport is blocked in the anode region lacking electrolyte. The uniform distribution of electrolyte is crucial for the construction of safe lithium-ion batteries especially in fast charging scenarios.展开更多
Estimating battery degradation is vital not only to monitor battery’s state-of-health but also to accelerate research on new battery chemistries. Herein, we present a data-driven approach to forecast the capacity fad...Estimating battery degradation is vital not only to monitor battery’s state-of-health but also to accelerate research on new battery chemistries. Herein, we present a data-driven approach to forecast the capacity fading trajectory of lab-assembled lithium batteries. Features with physical meanings in addition to predictive abilities are extracted from discharge voltage curves, enabling online prediction for a single cell with only its historical data. The robustness and generalizability allow for the demonstration on a compromised quality dataset consisting of batteries varying in battery architectures and cycling conditions,with superior accuracy for end of life and degradation trajectory prediction with average errors of 8.2%and 2.8%, respectively. Apart from the impressive prediction accuracy, the as-extracted features also provide physical insights, the incorporation of which into material design or battery operation conditions further enlightens the development of better batteries. We highlight the effectiveness of time-seriesbased techniques in forecasting battery cycling performance, as well as the huge potential of datadriven methods in unveiling hidden correlations in complicated energy chemistries such as lithium metal batteries.展开更多
The high specific capacity and energy density of lithium-sulfur batteries have attracted strong considerations on their fundamental mechanism and energy applications.However,polysulfide shuttle is still the key issue ...The high specific capacity and energy density of lithium-sulfur batteries have attracted strong considerations on their fundamental mechanism and energy applications.However,polysulfide shuttle is still the key issue that impedes the development of Li-S batteries.Exploring nanocrystal hosts for polysulfide immobilization and conversion is a promising way.In this contribution,we have investigated well-dispersed Co9S8 nanocrystals grown on graphene oxide(GO)nanosheets with different degrees of dispersion as cathode host materials for Li-S batteries.The Co9S8-GO composite with 1 wt%GO(GCS1)has an average crystal size of 76 nm and shows the strongest adsorption capability toward lithium polysulfides.When used as the host material for the cathode of Li-S batteries,the GCS1-sulfur composite exhibits an initial specific capacity of^-1000 mAh g^-1 at 0.5 C and shows an average decay rate of 0.11%for 500 cycles.This work on the dispersion control of Co9S8 nanocrystals may inspire more investigations on well-dispersed nanocrystal based hosts for Li-S batteries.展开更多
Hard carbons are widely investigated as potential anodes for lithium and sodium ion batteries owing to their internally well-tailored textures(closed pores and defects) and large microcrystalline interlayer spacing. T...Hard carbons are widely investigated as potential anodes for lithium and sodium ion batteries owing to their internally well-tailored textures(closed pores and defects) and large microcrystalline interlayer spacing. The renewable biomass is a green and economically attractive carbon source to produce hard carbons. However, the chemical and structural complexity of biomass has plagued the understanding of evolution mechanism from organic precursors to hard carbons and the structure-property relationship.This makes it difficult to finely tune the microstructure of biomass-derived hard carbons, thus greatly restricting their high-performance applications. Most recently, the optimal utilization and controllable conversion of biomass-derived biopolymers(such as starch, cellulose and lignin) at the molecular level have become a burgeoning area of research to develop hard carbons for advanced batteries.Considering the principal source of carbonaceous materials is from biomass pyrolysis, we firstly overview the chemical structures and pyrolysis behaviors of three main biopolymers. Then, the controllable preparation of hard carbons using various physicochemical properties of biopolymers at the molecular level is systematically discussed. Furthermore, we highlight present challenges and further opportunities in this field. The Review will guide future research works on the design of sustainable hard carbons and the optimization of battery performance.展开更多
基金supported by the National Key Research and Development Program (2016YFA0202500, 2015CB932500, and 2016YFA0200102)the National Natural Science Foundation of China (21676160, 21825501, 21805161, and 21808125)China Postdoctoral Science Foundation (2017M620773, 2018M631480, and BX201700125)
文摘Lithium (Li) metal with an ultrahigh specific theoretical capacity and the lowest reduction potential is strongly considered as a promising anode for high-energy-density batteries. However, uncontrolled lithium dendrites and infinite volume change during repeated plating/stripping cycles hinder its practical applications immensely. Herein, a house-like Li anode (housed Li) was designed to circumvent the above issues. The house matrix was composed of carbon fiber matrix and affords a stable structure to relieve the volume change. An artificial solid electrolyte layer was formed on composite Li metal, just like the roof of a house, which facilitates uniform Li ions diffusion and serves as a physical barrier against electrolyte corrosion. With the combination of solid electrolyte layer and matrix in the composite Li metal anode, both dendrite growth and volume expansion are remarkably inhibited. The housed Li|LiFePO4 batteries exhibited over 95% capacity retention after 500 cycles at 1.0 C in coin cell and 85% capacity retention after 80 cycles at 0.5 C in pouch cell. The rationally combination of solid electrolyte layer protection and housed framework in one Li metal anode sheds fresh insights on the design principle of a safe and long-lifespan Li metal anode for Li metal batteries.
基金supported by National Key Research and Development Program (2016YFA0202500)the National Natural Science Foundation of China (21776019, and 21808124)Beijing Natural Science Foundation (L182021)。
文摘As an efficient and environmental friendly energy storage system, lithium battery has been integrated into daily mobile life [1].Lithium batteries are becoming indispensable to all types of electronic products such as laptop computers, mobile phones, digital cameras [2]. A typical lithium battery consists of positive electrode(cathode), negative electrode(anode), electrolyte and other inactive materials(binder, conductive agent, separator) [3].
基金supported by the Beijing Natural Science Foundation(JQ20004,L182021)the National Natural Science Foundation of China(21808124)the National Key Research and Development Program(2016YFA0202500)。
文摘Solid electrolyte interphase(SEI)has been widely recognized as the most important and the least understood component in lithium batteries.Considering the intrinsic instability in both chemical and mechanical,the failure of SEI is inevitable and strongly associated with the performance decay of practical working batteries.In this Review,the failure mechanisms and the corresponding regulation strategies of SEI are focused.Firstly,the fundamental properties of SEI,including the formation principles,and the typical composition and structures are briefly introduced.Moreover,the common SEI failure modes involving thermal failure,chemical failure,and mechanical failure are classified and discussed,respectively.Beyond that,the regulation strategies of SEI with respect to different failure modes are further concluded.Finally,the future endeavor in further disclosing the mysteries of SEI is prospected.
基金supported by the National Key Research and Development Program(2016YFA0202500)National Natural Science Foundation of China(21776019,21808124,51972121)+1 种基金Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2017TQ04C419)Beijing Natural Science Foundation(L182021)。
文摘Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactive lithium metal result in the severe safety risks and the short lifespan for highenergy-density rechargeable batteries.Here,we demonstrate a hydrophobic and ionically conductive ethylene-vinyl acetate(EVA)copolymer layer can not only endow lithium metal anodes with an air-stable and anti-water surface,but also efficiently suppress the lithium-dendrites growth during the electrochemical cycling process.Therefore,the introduction of the EVA copolymer as a bifunctional protection layer simultaneously improves the anti-water/air performance and electrochemical cycling stability of lithium metal anode.
基金supported by National Key Research and Development Program(2016YFA0202500)the National Natural Science Foundation of China(21776019)Beijing Natural Science Foundation(L182021)。
文摘Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase(SEI)covered on the graphite anode determines the service life of a battery.The formation method and the formation temperature at initial cycle of a battery determine the feature of the SEI.Herein,we investigate the gap of formation behavior in both a half cell(graphite matches with lithium anode)and a full cell(graphite matches with NCM,short for LiNixCoyMn1-x-yO2)at different temperatures.We conclude that high temperature causes severe side reactions and low temperature will result in low ionic conductive SEI layer,the interface formed at room temperature owns the best ionic conductivity and stability.
基金This work was supported by the Beijing Municipal Natural Science Foundation(Z20J00043)the National Natural Science Foundation of China(21825501)+1 种基金the National Key Research and Development Program(2016YFA0202500)the Tsinghua University Initiative Scientific Research Program.
文摘Lithium (Li) metal attributes to the promising anode but endures the low Columbic efficiency (CE) and safety issues from the inactive Li accumulation. The metallic Li which is isolated from the lithium anode (named dead Li^(0)) consists the major component of the inactive Li. We systematically and meticulously investigated the formation and evaluation of dead Li^(0) during stripping process from electron transfer, the oxidation of Li^(0) to Li^(+) and the diffusion of Li^(+) through solid electrolyte interphase (SEI). The above-mentioned processes were regulated by adjusting the contact sites of electron channels, the dynamic rate of conversion from Li^(0) to Li^(+), and the structure as well as components of SEI. The design principles for achieving less dead Li^(0) and higher CE are proposed as a proof of concept in lithium metal batteries. This new insight sheds a comprehensive light on dead Li^(0) formation and guides the next-generation safe batteries for future application.
基金supported by the National Natural Science Foundation of China(21808124,22075029)by Beijing Natural Science Foundation(JQ20004)+2 种基金by Scientific and Technological Key Project of Shanxi Province(20191102003)the Seed Fund of Shanxi Research Institute for Clean Energy(SXKYJF015)the Shuimu Tsinghua Scholar Program,and Tsinghua University Initiative Scientific Research Program。
文摘Lithium plating in working batteries has attracted wide attention in the exploration of safe energy storage. Establishing an effective and rapid early-warning method is strongly considered but quite challenging since lithium plating behavior is determined by diverse factors. In this contribution, we present a non-destructive electrochemical detection method based on transient state analysis and threeelectrode cell configuration. Through dividing the iR drop value by the current density, the as-obtained impedance quantity(R_(i)) can serve as a descriptor to describe the change of electrochemical reaction impedance on the graphite anode. The onset of lithium plating can be identified from the sharp drop of R_(i). Once the dendritic plated lithium occurs, the extra electrochemical reactions at the lithium interfaces leads to growing active area and reduced surface resistance of the anode. We proposed a protocol to operate the batteries under the limited capacity, which renders the cell with 98.2% capacity retention after 1000 cycles without lithium plating. The early-warning method has also been validated in in-situ optical microscopy batteries and practical pouch cells, providing a general but effective method for online lithium plating detection towards safe batteries.
基金supported by the National Key Research and Development Program(2018YFB1501500)the National Science Foundation for Excellent Young Scholars of China(21922815)+2 种基金the National Key Research and Development(R&D)Program of China(2020YFB1505800)the Research and Development Project of Key Core and Common Technology of Shanxi Province(2020XXX014)the Fundamental Research Program of Shanxi Province(20210302123008,20210302124101)。
文摘Lithium-sulfur battery(LSB) has high energy density but is limited by the polysulfides shuttle and dendrite growth during cycling. Herein, a free-standing cellulose nanofiber(CNF) separator is designed and fabricated in isopropanol/water suspension through vacuum filtration progress. CNFs with abundant polar oxygen-containing functional groups can chemically immobilize the polysulfides, and suppress the formation of the dendrites by controlling the surface morphology of the SEI on lithium metal in LSB. The isopropanol content in a suspension can fine-tune the pore structure of the membrane to achieve optimal electrochemical performance. The prepared separator displays integrated advantages of an ultrathin thickness(19 μm), lightweight(0.87 mg cm^(-2)), extremely high porosity(98.05%), and decent electrolyte affinity. As a result, the discharge capacity of the LSB with CNF separator at the first and 100 th cycle is 1.4 and 1.3 times that of PP separator, respectively. Our research provides an environmentalfriendly and facile strategy for the preparation of multifunctional separators for LSBs.
基金This work was supported by National Key Research and Development Program(2016YFA0202500,2015CB932500,and 2016YFA0200102)National Natural Scien-tific Foundation of China(21776019,21676160,and 21711540019)+1 种基金China Post-doctoral Science Foundation(2018M630165)Beijing Key Research and Development Plan(Z181100004518001).
文摘Magnesium–sulfur batteries promise high volumetric energy density,enhanced safety,and low cost for electrochemical energy storage.The current obstacles to practical applications of reliable magnesium–sulfur batteries are finding electrolytes that can meet a multitude of rigorous requirements along with efficient sulfur cathodes and magnesium anodes.This review highlights recent advances in designing better electrolytes,cathodes,and anodes.A suitable electrolyte for magnesium-sulfur batteries should allow to reversibly electroplate/strip divalent magnesium ions and should be compatible with the sulfur cathode and the other cell’s components.
基金supported by the Beijing Natural Science Foundation (JQ20004)the National Key Research and Development Program (2021YFB2400300)+1 种基金the National Natural Science Foundation of China (22109083)the Scientific and Technological Key Project of Shanxi Province (20191102003)。
文摘Fast charging capability of lithium-ion batteries is in urgent need for widespread economic success of electric vehicles. However, the application of the fast charging technology often leads to the inevitable lithium plating on the graphite anode, which is one of the main culprits that endanger battery safety and shorten battery lifespan. The in-depth understanding of the initiation of lithium metal nucleation and the following plating behavior is a key to the development of fast charging cells. Herein, we investigate the overlooked effect of the non-uniform distribution of electrolyte on lithium plating during fast charging. Prior lithium plating occurs on the saturated lithium-graphite compounds in the anode region with sufficient electrolyte since the lithium-ion transport is blocked in the anode region lacking electrolyte. The uniform distribution of electrolyte is crucial for the construction of safe lithium-ion batteries especially in fast charging scenarios.
基金supported by the Beijing Municipal Natural Science Foundation (Z20J00043)the National Natural Science Foundation of China (21825501, 22109020, 22109082, and U1801257)+2 种基金the National Key Research and Development Program(2016YFA0202500)the Tsinghua University Initiative Scientific Research Programthe University of Electronic Science and Technology of China for its financial support through the Start-Up Fund for Outstanding Talent with grant number A1098531023601307。
文摘Estimating battery degradation is vital not only to monitor battery’s state-of-health but also to accelerate research on new battery chemistries. Herein, we present a data-driven approach to forecast the capacity fading trajectory of lab-assembled lithium batteries. Features with physical meanings in addition to predictive abilities are extracted from discharge voltage curves, enabling online prediction for a single cell with only its historical data. The robustness and generalizability allow for the demonstration on a compromised quality dataset consisting of batteries varying in battery architectures and cycling conditions,with superior accuracy for end of life and degradation trajectory prediction with average errors of 8.2%and 2.8%, respectively. Apart from the impressive prediction accuracy, the as-extracted features also provide physical insights, the incorporation of which into material design or battery operation conditions further enlightens the development of better batteries. We highlight the effectiveness of time-seriesbased techniques in forecasting battery cycling performance, as well as the huge potential of datadriven methods in unveiling hidden correlations in complicated energy chemistries such as lithium metal batteries.
基金supported by the National Science Fund for Distinguished Young Scholars(51425204,21825501)the National Natural Science Foundation of China(21776019,51832004 and U1801257)+3 种基金the National Key R&D Program of China(2016YFA0202603,2016YFA0202500)the Yellow Crane Talent(Science&Technology)Program of Wuhan Citythe Tsinghua University Initiative Scientific Research Programthe National Basic Research Program of China(2013CB934103)。
文摘The high specific capacity and energy density of lithium-sulfur batteries have attracted strong considerations on their fundamental mechanism and energy applications.However,polysulfide shuttle is still the key issue that impedes the development of Li-S batteries.Exploring nanocrystal hosts for polysulfide immobilization and conversion is a promising way.In this contribution,we have investigated well-dispersed Co9S8 nanocrystals grown on graphene oxide(GO)nanosheets with different degrees of dispersion as cathode host materials for Li-S batteries.The Co9S8-GO composite with 1 wt%GO(GCS1)has an average crystal size of 76 nm and shows the strongest adsorption capability toward lithium polysulfides.When used as the host material for the cathode of Li-S batteries,the GCS1-sulfur composite exhibits an initial specific capacity of^-1000 mAh g^-1 at 0.5 C and shows an average decay rate of 0.11%for 500 cycles.This work on the dispersion control of Co9S8 nanocrystals may inspire more investigations on well-dispersed nanocrystal based hosts for Li-S batteries.
基金the support of this work by the Fundamental Research Program of Shanxi Province(20210302123008,20210302124101)the Youth Innovation Promotion Association of CAS(2019178)+1 种基金the National Science Foundation for Excellent Young Scholars of China(21922815)the National Natural Science Foundation of China(21975275,22179139)。
文摘Hard carbons are widely investigated as potential anodes for lithium and sodium ion batteries owing to their internally well-tailored textures(closed pores and defects) and large microcrystalline interlayer spacing. The renewable biomass is a green and economically attractive carbon source to produce hard carbons. However, the chemical and structural complexity of biomass has plagued the understanding of evolution mechanism from organic precursors to hard carbons and the structure-property relationship.This makes it difficult to finely tune the microstructure of biomass-derived hard carbons, thus greatly restricting their high-performance applications. Most recently, the optimal utilization and controllable conversion of biomass-derived biopolymers(such as starch, cellulose and lignin) at the molecular level have become a burgeoning area of research to develop hard carbons for advanced batteries.Considering the principal source of carbonaceous materials is from biomass pyrolysis, we firstly overview the chemical structures and pyrolysis behaviors of three main biopolymers. Then, the controllable preparation of hard carbons using various physicochemical properties of biopolymers at the molecular level is systematically discussed. Furthermore, we highlight present challenges and further opportunities in this field. The Review will guide future research works on the design of sustainable hard carbons and the optimization of battery performance.