As promising energy storage systems,lithium-sulfur(Li-S)batteries have attracted significant attention because of their ultra-high energy densities.However,Li-S battery suffers problems related to the complex phase co...As promising energy storage systems,lithium-sulfur(Li-S)batteries have attracted significant attention because of their ultra-high energy densities.However,Li-S battery suffers problems related to the complex phase conversion that occurs during the charge-discharge process,particularly the deposition of solid Li2S from the liquid-phase polysulfides,which greatly limits its practical application.In this paper,edge-rich MoS2/C hollow microspheres(Edg-MoS2/C HMs)were designed and used to functionalize separator for Li-S battery,resulting in the uniform deposition of Li2S.The microspheres were fabricated through the facile hydrothermal treatment of MoO3-aniline nanowires and a subsequent carbonization process.The obtained Edg-MoS2/C HMs have a strong chemical absorption capability and high density of Li2S binding sites,and exhibit excellent electrocatalytic performance and can effectively hinder the polysulfide shuttle effect and guide the uniform nucleation and growth of Li2S.Furthermore,we demonstrate that the Edg-MoS2/C HMs can effectively regulate the deposition of Li2S and significantly improve the reversibility of the phase conversion of the active sulfur species,especially at high sulfur loadings and high C-rates.As a result,a cell containing a separator functionalized with Edg-MoS2/C HMs exhibited an initial discharge capacity of 935 mAh g-1 at 1.0 C and maintained a capacity of 494 mAh g-1 after 1000 cycles with a sulfur loading of 1.7 mg cm-2.Impressively,at a high sulfur loading of 6.1 mg cm-2 and high rate of 0.5 C,the cell still delivered a high reversible discharge capacity of 478 mAh g-1 after 300 cycles.This work provides fresh insights into energy storage systems related to complex phase conversions.展开更多
Lithium-sulfur(Li-S)system coupled with thin-film solid electrolyte as a novel high-energy micro-battery has enormous potential for complementing embedded energy harvesters to enable the autonomy of the Internet of Th...Lithium-sulfur(Li-S)system coupled with thin-film solid electrolyte as a novel high-energy micro-battery has enormous potential for complementing embedded energy harvesters to enable the autonomy of the Internet of Things microdevice.However,the volatility in high vacuum and intrinsic sluggish kinetics of S hinder researchers from empirically integrating it into allsolid-state thin-film batteries,leading to inexperience in fabricating all-solid-state thin-film Li-S batteries(TFLSBs).Herein,for the first time,TFLSBs have been successfully constructed by stacking vertical graphene nanosheets-Li2S(VGsLi2S)composite thin-film cathode,lithium-phosphorous-oxynitride(LiPON)thin-film solid electrolyte,and Li metal anode.Fundamentally eliminating Lipolysulfide shuttle effect and maintaining a stable VGs-Li2S/LiPON interface upon prolonged cycles have been well identified by employing the solid-state Li-S system with an“unlimited Li”reservoir,which exhibits excellent longterm cycling stability with a capacity retention of 81%for 3,000 cycles,and an exceptional high temperature tolerance up to 60℃.More impressively,VGs-Li2S-based TFLSBs with evaporated-Li thin-film anode also demonstrate outstanding cycling performance over 500 cycles with a high Coulombic efficiency of 99.71%.Collectively,this study presents a new development strategy for secure and high-performance rechargeable all-solid-state thin-film batteries.展开更多
Lithium–sulfur batteries have been attracting considerable research attention due to their high energy densities and low costs. However, one of their main challenges is the undesired shuttling of polysulfides, causin...Lithium–sulfur batteries have been attracting considerable research attention due to their high energy densities and low costs. However, one of their main challenges is the undesired shuttling of polysulfides, causing rapid capacity degradation. Herein, we report the first example of sulfiphilic VSe2 ultrafine nanocrystals immobilized on nitrogen-doped graphene to modify the battery separator for alleviating the shuttling problem. VSe2 nanocrystals provide numerous active sites for chemisorption of polysulfides as well as benefit the nucleation and growth of Li2S. Furthermore, the kinetic reactions are accelerated which is confirmed by higher exchange current density and higher lithium ion diffusion coefficient. And the first-principles calculations further show that the exposed sulfiphilic planes of VSe2 boost the redox of Li2S. When used as separators within the lithium sulfur batteries, the cell indicates greatly enhanced electrochemical performances with excellent long cycling stability and exceptional rate capability up to 8 C. Moreover, it delivers a higher areal capacity of 4.04 mAh·cm^−2 as well as superior cycling stability with sulfur areal loading up to 6.1 mg·cm^−2. The present strategy can encourage us in engineering novel multifunctional separators for energy-storage devices.展开更多
High energy density and low cost made lithium–sulfur(Li–S)batteries appealing for the next-generation energy storage devices.However,their commercial viability is seriously challenged by serious polysulfide shuttle ...High energy density and low cost made lithium–sulfur(Li–S)batteries appealing for the next-generation energy storage devices.However,their commercial viability is seriously challenged by serious polysulfide shuttle effect,sluggish sulfur kinetics,and uncontrollable dendritic Li growth.Herein,a dual-functional electrolyte additive,diphenyl ditelluride(DPDTe)is reported for Li–S battery.For sulfur cathodes,DPDTe works as a redox mediator to accelerate redox kinetics of sulfur,in which Te radical-mediated catalytic cycle at the solid–liquid interface contributes significantly to the whole process.For lithium anodes,DPDTe can react with lithium metal to form a smooth and stable organic–inorganic hybrid solid-electrolyte interphase(SEI),enabling homogeneous lithium deposition for suppressing dendrite growth.Consequently,the Li–S battery with DPDTe exhibits remarkable cycling stability and superb rate capability,with a high capacity up to 1227.3 mAh g^(-1)and stable cycling over 300 cycles.Moreover,a Li–S pouch cell with DPDTe is evaluated as the proof of concept.This work demonstrates that organotelluride compounds can be used as functional electrolyte additives and offers new insights and opportunities for practical Li–S batteries.展开更多
Lithium-ion batteries are widely used in portable electronics and electric vehicles due to their high energy density,stable cycle life,and low self-discharge.However,irreversible lithium loss during the formation of t...Lithium-ion batteries are widely used in portable electronics and electric vehicles due to their high energy density,stable cycle life,and low self-discharge.However,irreversible lithium loss during the formation of the solid electrolyte interface greatly impairs energy density and cyclability.To compensate for the lithium loss,introducing an external lithium source,that is,a prelithiation agent,is an effective strategy to solve the above problems.Compared with other prelithiation strategies,cathode prelithiation is more cost-effective with simpler operation.Among various cathode prelithiation agents,we first systematically summarize the recent progress of Li_(2)S-based prelithiation agents,and then propose some novel strategies to tackle the current challenges.This review provides a comprehensive understanding of Li_(2)S-based prelithiation agents and new research directions in the future.展开更多
Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2...Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2S cathode has lower volume expansion and higher thermal stability than the traditional sulfur cathode.However,the problems of"shuttle effect"and poor electrical conductivity of the cathode material still need to be overcome.In this work,multi-layered Ti3C2/Li2S(ML-Ti3C2/Li2S)composite has been prepared and applied as a cathode in advanced Li-S batteries.The unique multi-layer sheet structure of Ti3 C2 provides space for the storage of Li2S,and its good conductivity greatly enhances the usage ratio of Li2 S and improves the conductivity of the whole Li2S cathode.Compared with commonly used graphene,ML-Ti3C2 can trap polysulfides effectively by chemical adsorption and also activate the reaction of Li2S to polysulfides by forming Ti-S bond.As a result,during the cycling of the batteries with ML-Ti3C2/Li2S cathodes,the activation voltage barrier of the first cycle has decreased to 2.8 V,and the"shuttle effect"has been suppressed effectively.The cycling and rate performances of the ML-Ti3C2/Li2S cathodes have been significantly improved compared to that of graphene/Li2 S cathodes.They maintain a capacity of 450 mAh g^-1 at 0.2 C after 100 cycles,and deliver attractive rate performances of 750,630,540,470 and 360 mAh g^-1 at 0.1 C,0.2 C,0.5 C,1 C,and 2 C,respectively.展开更多
Tremendous effort has been devoted to lithium‐sulfur batteries,where flooded electrolytes have been employed ubiquitously.The use of lean electrolytes albeit indispensable for practical applications often causes low ...Tremendous effort has been devoted to lithium‐sulfur batteries,where flooded electrolytes have been employed ubiquitously.The use of lean electrolytes albeit indispensable for practical applications often causes low capacity and fast capacity fading of the sulfur cathode;thus,the electrolyte/sulfur active mass ratios below 5μL/mg have been rarely reported.Herein,we demonstrate that ZnS coating transforms sulfur cathode materials electrolyte‐philic,which tremendously promotes the performance in lean electrolytes.The ZnS‐coated Li2S@graphene cathode delivers an initial discharge capacity of 944mAh/g at an E/S ratio of 2μL/mg at the active mass loading of 5.0 mg Li2S/cm^2,corresponding to an impressive specific energy of 500Wh/kg based on the mass of cathode,electrolyte,and the assumed minimal mass of lithium metal anode.Density functional theory calculations reveal strong binding between ZnS crystals and electrolyte solvent molecules,explaining the better wetting properties.We also demonstrate the reversible cycling of a hybrid cathode of ZnS‐coated Li2S@graphene mixed with VS2 as an additive at an E/AM(active mass)ratio of 1.1μL/mg,equivalent to the specific energy of 432 Wh/kg on the basis of the mass of electrodes and electrolyte.展开更多
Sulfur utilization improvement and control of dissolved lithium polysulfide(LiPS;Li_(2)S x,2<x≤8)are cru-cial aspects of the development of lithium-sulfur(Li-S)batteries,especially in high-loading sulfur elec-trode...Sulfur utilization improvement and control of dissolved lithium polysulfide(LiPS;Li_(2)S x,2<x≤8)are cru-cial aspects of the development of lithium-sulfur(Li-S)batteries,especially in high-loading sulfur elec-trodes and low electrolyte/sulfur(E/S)ratios.The sluggish reaction in the low E/S ratio induces poor LiPS solubility and unstable Li_(2)S electrodeposition,resulting in limited sulfur utilization,especially under high-loading sulfur electrode.In this study,we report on salt concentration effects that improve sulfur utilization with a high-loading cathode(6 mgs ulfurcm^(-2)),a high sulfur content(80 wt%)and a low E/S ratio(5 m L gs ulfur^(-1)).On the basis of the rapid LiPS dissolving in a low concentration electrolyte,we estab-lished that the quantity of Li_(2)S electrodeposition from a high Li+diffusion coefficient,referring to the reduction of LiPS precipitation,was significantly enhanced by a faster kinetic.These results demonstrate the importance of kinetic factors for the rate capability and cycle life stability of Li-S battery electrolytes through high Li_(2)S deposition under high-loading sulfur electrode.展开更多
Lithium sulfide(Li_(2)S)is a promising cathode for a practical lithium-sulfur battery as it can be coupled with various safe lithium-free anodes.However,the high activation potential(>3.5 V)together with the shuttl...Lithium sulfide(Li_(2)S)is a promising cathode for a practical lithium-sulfur battery as it can be coupled with various safe lithium-free anodes.However,the high activation potential(>3.5 V)together with the shuttling of lithium polysulfides(LiPSs)bottleneck its practical uses.We are trying to present a catalysis solution to solve both problems simultaneously,specially with twinborn heterostructure to shoot off the trouble in interfacial contact between two solids,catalyst and Li_(2)S.As a typical example,a Co9S8/Li_(2)S heterostructure is reported here as a novel self-catalytic cathode through a co-recrystallization followed by a one-step carbothermic conversion.Co9S8 as the catalyst effectively lowers the Li_(2)S activation potential(<2.4 V)due to fully integrated and contacted interfaces and consistently promotes the conversion of LiPSs to suppress the shuttling.The obtained freestanding cathode of Co9S8/Li_(2)S heterostructures encapsulated in three-dimensional graphene shows a high capacity,reaching 92.6%of Li_(2)S theoretical capacity,high rate performance(739 mAh g1 at 2 C),and a low capacity fading(0.039%per cycle at 1 C over 900 cycles).Even under a high Li_(2)S loading of 12 mg cm^(-2)and a low E/S ratio of 5μL mgLi_(2)S^(-1),86%of theoretical capacity can be utilized.展开更多
利用高温固相反应法制备了新型三元锂离子电池正极材料Li2Ru1/3Co1/3M1/3O3(M=Mn、Ni、Fe)。通过X射线衍射技术和电化学性能测试对Li2Ru1/3Co1/3M1/3O3的微观结构及其电化学性能进行了表征。研究结果表明,Li2Ru1/3Co1/3Ni1/3O3和Li2Ru1/...利用高温固相反应法制备了新型三元锂离子电池正极材料Li2Ru1/3Co1/3M1/3O3(M=Mn、Ni、Fe)。通过X射线衍射技术和电化学性能测试对Li2Ru1/3Co1/3M1/3O3的微观结构及其电化学性能进行了表征。研究结果表明,Li2Ru1/3Co1/3Ni1/3O3和Li2Ru1/3Co1/3Fe1/3O3为六方层状结构,空间群为R-3M,而Li2Ru1/3Co1/3Mn1/3O3保持了单斜结构;电化学性能测试表明Li2Ru1/3Co1/3Mn1/3O3的电化学性能优于掺杂Fe和Ni的三元材料,该材料具有良好的循环性能,在电流密度为16 m A/g情况下,首次充电容量达到190 m Ah/g,首次放电容量为171 m Ah/g,50次循环后容量保持率为98%。展开更多
用光学 光学双共振激光光谱研究了 7Li2 A1Σ+ u 态的Autler Townes (A T)分裂 .一个强的耦合场 (泵浦激光 )激发 7Li2 A1Σ+ u v′ ,J′←X1Σ+ g v″,J″跃迁 ,诱发A1Σ+ u v′ ,J′能级和X1Σ+ g v″ ,J″能级的A T分裂 .另一个探测...用光学 光学双共振激光光谱研究了 7Li2 A1Σ+ u 态的Autler Townes (A T)分裂 .一个强的耦合场 (泵浦激光 )激发 7Li2 A1Σ+ u v′ ,J′←X1Σ+ g v″,J″跃迁 ,诱发A1Σ+ u v′ ,J′能级和X1Σ+ g v″ ,J″能级的A T分裂 .另一个探测激光从A1Σ+ u v′ ,J′能级进一步激发到 4 1Σ+ g 态 .扫描探测激光 ,监测 4 1Σ+ g 态碰撞诱导紫色荧光 ,从而探测A1Σ+ u v′,J′能级的A T分裂 .当耦合场频率偏离共振时 ,激发光谱线出现双重分裂 .在该实验条件下 ,分裂大小和泵浦激光频率偏离共振频率的失谐量成正比 .研究了A T分裂的两条线的相对强度与泵浦、探测光的强度及缓冲气体压力的关系 .展开更多
基金financially supported by National Natural Science Foundation of China (No. 51672083)Program of Shanghai Academic/Technology Research Leader (18XD1401400)+3 种基金Basic Research Program of Shanghai (17JC1404702)Leading talents in Shanghai in 2018The 111 project (B14018)the Fundamental Research Funds for the Central Universities (222201718002)
文摘As promising energy storage systems,lithium-sulfur(Li-S)batteries have attracted significant attention because of their ultra-high energy densities.However,Li-S battery suffers problems related to the complex phase conversion that occurs during the charge-discharge process,particularly the deposition of solid Li2S from the liquid-phase polysulfides,which greatly limits its practical application.In this paper,edge-rich MoS2/C hollow microspheres(Edg-MoS2/C HMs)were designed and used to functionalize separator for Li-S battery,resulting in the uniform deposition of Li2S.The microspheres were fabricated through the facile hydrothermal treatment of MoO3-aniline nanowires and a subsequent carbonization process.The obtained Edg-MoS2/C HMs have a strong chemical absorption capability and high density of Li2S binding sites,and exhibit excellent electrocatalytic performance and can effectively hinder the polysulfide shuttle effect and guide the uniform nucleation and growth of Li2S.Furthermore,we demonstrate that the Edg-MoS2/C HMs can effectively regulate the deposition of Li2S and significantly improve the reversibility of the phase conversion of the active sulfur species,especially at high sulfur loadings and high C-rates.As a result,a cell containing a separator functionalized with Edg-MoS2/C HMs exhibited an initial discharge capacity of 935 mAh g-1 at 1.0 C and maintained a capacity of 494 mAh g-1 after 1000 cycles with a sulfur loading of 1.7 mg cm-2.Impressively,at a high sulfur loading of 6.1 mg cm-2 and high rate of 0.5 C,the cell still delivered a high reversible discharge capacity of 478 mAh g-1 after 300 cycles.This work provides fresh insights into energy storage systems related to complex phase conversions.
基金supported by National Natural Science Foundation of China(No.U22A20118)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR146,2021ZZ122)Award Program for Fujian Minjiang Scholar Professorship。
文摘Lithium-sulfur(Li-S)system coupled with thin-film solid electrolyte as a novel high-energy micro-battery has enormous potential for complementing embedded energy harvesters to enable the autonomy of the Internet of Things microdevice.However,the volatility in high vacuum and intrinsic sluggish kinetics of S hinder researchers from empirically integrating it into allsolid-state thin-film batteries,leading to inexperience in fabricating all-solid-state thin-film Li-S batteries(TFLSBs).Herein,for the first time,TFLSBs have been successfully constructed by stacking vertical graphene nanosheets-Li2S(VGsLi2S)composite thin-film cathode,lithium-phosphorous-oxynitride(LiPON)thin-film solid electrolyte,and Li metal anode.Fundamentally eliminating Lipolysulfide shuttle effect and maintaining a stable VGs-Li2S/LiPON interface upon prolonged cycles have been well identified by employing the solid-state Li-S system with an“unlimited Li”reservoir,which exhibits excellent longterm cycling stability with a capacity retention of 81%for 3,000 cycles,and an exceptional high temperature tolerance up to 60℃.More impressively,VGs-Li2S-based TFLSBs with evaporated-Li thin-film anode also demonstrate outstanding cycling performance over 500 cycles with a high Coulombic efficiency of 99.71%.Collectively,this study presents a new development strategy for secure and high-performance rechargeable all-solid-state thin-film batteries.
基金The authors acknowledge the financial supports provided by the National Natural Science Foundation of China(Nos.21871164,21803036,and U1764258)the Taishan Scholar Project Foundation of Shandong Province(Nos.ts20190908 and ts201511004)the National Science Foundation of Shandong Province(No.ZR2019MB024).The theoretical calculations in this work were performed on the HPC Cloud Platform of Shandong University.We also thank Anhui Kemi Machinery Technology Co,Ltd for providing Teflon-lined stainless steel autoclave.
文摘Lithium–sulfur batteries have been attracting considerable research attention due to their high energy densities and low costs. However, one of their main challenges is the undesired shuttling of polysulfides, causing rapid capacity degradation. Herein, we report the first example of sulfiphilic VSe2 ultrafine nanocrystals immobilized on nitrogen-doped graphene to modify the battery separator for alleviating the shuttling problem. VSe2 nanocrystals provide numerous active sites for chemisorption of polysulfides as well as benefit the nucleation and growth of Li2S. Furthermore, the kinetic reactions are accelerated which is confirmed by higher exchange current density and higher lithium ion diffusion coefficient. And the first-principles calculations further show that the exposed sulfiphilic planes of VSe2 boost the redox of Li2S. When used as separators within the lithium sulfur batteries, the cell indicates greatly enhanced electrochemical performances with excellent long cycling stability and exceptional rate capability up to 8 C. Moreover, it delivers a higher areal capacity of 4.04 mAh·cm^−2 as well as superior cycling stability with sulfur areal loading up to 6.1 mg·cm^−2. The present strategy can encourage us in engineering novel multifunctional separators for energy-storage devices.
基金supported by the National Natural Sci-ence Foundation of China(Nos.21975087,U1966214)the Certificate of China Postdoctoral Science Foundation Grant(2020M672337).
文摘High energy density and low cost made lithium–sulfur(Li–S)batteries appealing for the next-generation energy storage devices.However,their commercial viability is seriously challenged by serious polysulfide shuttle effect,sluggish sulfur kinetics,and uncontrollable dendritic Li growth.Herein,a dual-functional electrolyte additive,diphenyl ditelluride(DPDTe)is reported for Li–S battery.For sulfur cathodes,DPDTe works as a redox mediator to accelerate redox kinetics of sulfur,in which Te radical-mediated catalytic cycle at the solid–liquid interface contributes significantly to the whole process.For lithium anodes,DPDTe can react with lithium metal to form a smooth and stable organic–inorganic hybrid solid-electrolyte interphase(SEI),enabling homogeneous lithium deposition for suppressing dendrite growth.Consequently,the Li–S battery with DPDTe exhibits remarkable cycling stability and superb rate capability,with a high capacity up to 1227.3 mAh g^(-1)and stable cycling over 300 cycles.Moreover,a Li–S pouch cell with DPDTe is evaluated as the proof of concept.This work demonstrates that organotelluride compounds can be used as functional electrolyte additives and offers new insights and opportunities for practical Li–S batteries.
基金National Natural Science Foundation of China,Grant/Award Number:22002045Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2023A1515030164+1 种基金Special Topics in Key Areas for Universities in Guangdong Province,Grant/Award Number:2023ZDZX3001Hong Kong Scholars Program 2022,Grant/Award Numbers:G-YZ5Y,XJ2022026。
文摘Lithium-ion batteries are widely used in portable electronics and electric vehicles due to their high energy density,stable cycle life,and low self-discharge.However,irreversible lithium loss during the formation of the solid electrolyte interface greatly impairs energy density and cyclability.To compensate for the lithium loss,introducing an external lithium source,that is,a prelithiation agent,is an effective strategy to solve the above problems.Compared with other prelithiation strategies,cathode prelithiation is more cost-effective with simpler operation.Among various cathode prelithiation agents,we first systematically summarize the recent progress of Li_(2)S-based prelithiation agents,and then propose some novel strategies to tackle the current challenges.This review provides a comprehensive understanding of Li_(2)S-based prelithiation agents and new research directions in the future.
基金financially supported by the National Natural Science Foundation of China(21606065,51372060,and 21676067)Anhui Provincial Natural Science Foundation(1708085QE98)+1 种基金the Fundamental Research Funds for the Central Universities(JZ2017HGTB0198,JZ2018HGBZ0138)the Opening Project of CAS Key Laboratory of Materials for Energy Conversion(KF2018003)
文摘Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2S cathode has lower volume expansion and higher thermal stability than the traditional sulfur cathode.However,the problems of"shuttle effect"and poor electrical conductivity of the cathode material still need to be overcome.In this work,multi-layered Ti3C2/Li2S(ML-Ti3C2/Li2S)composite has been prepared and applied as a cathode in advanced Li-S batteries.The unique multi-layer sheet structure of Ti3 C2 provides space for the storage of Li2S,and its good conductivity greatly enhances the usage ratio of Li2 S and improves the conductivity of the whole Li2S cathode.Compared with commonly used graphene,ML-Ti3C2 can trap polysulfides effectively by chemical adsorption and also activate the reaction of Li2S to polysulfides by forming Ti-S bond.As a result,during the cycling of the batteries with ML-Ti3C2/Li2S cathodes,the activation voltage barrier of the first cycle has decreased to 2.8 V,and the"shuttle effect"has been suppressed effectively.The cycling and rate performances of the ML-Ti3C2/Li2S cathodes have been significantly improved compared to that of graphene/Li2 S cathodes.They maintain a capacity of 450 mAh g^-1 at 0.2 C after 100 cycles,and deliver attractive rate performances of 750,630,540,470 and 360 mAh g^-1 at 0.1 C,0.2 C,0.5 C,1 C,and 2 C,respectively.
基金Office of Energy Efficiency and Renewable Energy,Grant/Award Number:DE‐FOA‐0001629U.S.Department of Energy,Grant/Award Number:DE‐AC02‐06CH11357。
文摘Tremendous effort has been devoted to lithium‐sulfur batteries,where flooded electrolytes have been employed ubiquitously.The use of lean electrolytes albeit indispensable for practical applications often causes low capacity and fast capacity fading of the sulfur cathode;thus,the electrolyte/sulfur active mass ratios below 5μL/mg have been rarely reported.Herein,we demonstrate that ZnS coating transforms sulfur cathode materials electrolyte‐philic,which tremendously promotes the performance in lean electrolytes.The ZnS‐coated Li2S@graphene cathode delivers an initial discharge capacity of 944mAh/g at an E/S ratio of 2μL/mg at the active mass loading of 5.0 mg Li2S/cm^2,corresponding to an impressive specific energy of 500Wh/kg based on the mass of cathode,electrolyte,and the assumed minimal mass of lithium metal anode.Density functional theory calculations reveal strong binding between ZnS crystals and electrolyte solvent molecules,explaining the better wetting properties.We also demonstrate the reversible cycling of a hybrid cathode of ZnS‐coated Li2S@graphene mixed with VS2 as an additive at an E/AM(active mass)ratio of 1.1μL/mg,equivalent to the specific energy of 432 Wh/kg on the basis of the mass of electrodes and electrolyte.
基金supported by a grant from the Korea Evaluation Institute of Industrial Technology(KEIT)funded by the Ministry of Trade,Industry and Energy(MOTIE)(No.20012341)。
文摘Sulfur utilization improvement and control of dissolved lithium polysulfide(LiPS;Li_(2)S x,2<x≤8)are cru-cial aspects of the development of lithium-sulfur(Li-S)batteries,especially in high-loading sulfur elec-trodes and low electrolyte/sulfur(E/S)ratios.The sluggish reaction in the low E/S ratio induces poor LiPS solubility and unstable Li_(2)S electrodeposition,resulting in limited sulfur utilization,especially under high-loading sulfur electrode.In this study,we report on salt concentration effects that improve sulfur utilization with a high-loading cathode(6 mgs ulfurcm^(-2)),a high sulfur content(80 wt%)and a low E/S ratio(5 m L gs ulfur^(-1)).On the basis of the rapid LiPS dissolving in a low concentration electrolyte,we estab-lished that the quantity of Li_(2)S electrodeposition from a high Li+diffusion coefficient,referring to the reduction of LiPS precipitation,was significantly enhanced by a faster kinetic.These results demonstrate the importance of kinetic factors for the rate capability and cycle life stability of Li-S battery electrolytes through high Li_(2)S deposition under high-loading sulfur electrode.
基金National Key Research and Development Program of China,Grant/Award Numbers:2018YFE0124500,2021YFF0500600National Natural Science Foundation of China,Grant/Award Numbers:52022041,51932005+1 种基金The Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program,Grant/Award Number:2017BT01N111Shenzhen Basic Research Project,Grant/Award Number:JCYJ20180508152037520。
文摘Lithium sulfide(Li_(2)S)is a promising cathode for a practical lithium-sulfur battery as it can be coupled with various safe lithium-free anodes.However,the high activation potential(>3.5 V)together with the shuttling of lithium polysulfides(LiPSs)bottleneck its practical uses.We are trying to present a catalysis solution to solve both problems simultaneously,specially with twinborn heterostructure to shoot off the trouble in interfacial contact between two solids,catalyst and Li_(2)S.As a typical example,a Co9S8/Li_(2)S heterostructure is reported here as a novel self-catalytic cathode through a co-recrystallization followed by a one-step carbothermic conversion.Co9S8 as the catalyst effectively lowers the Li_(2)S activation potential(<2.4 V)due to fully integrated and contacted interfaces and consistently promotes the conversion of LiPSs to suppress the shuttling.The obtained freestanding cathode of Co9S8/Li_(2)S heterostructures encapsulated in three-dimensional graphene shows a high capacity,reaching 92.6%of Li_(2)S theoretical capacity,high rate performance(739 mAh g1 at 2 C),and a low capacity fading(0.039%per cycle at 1 C over 900 cycles).Even under a high Li_(2)S loading of 12 mg cm^(-2)and a low E/S ratio of 5μL mgLi_(2)S^(-1),86%of theoretical capacity can be utilized.
文摘利用高温固相反应法制备了新型三元锂离子电池正极材料Li2Ru1/3Co1/3M1/3O3(M=Mn、Ni、Fe)。通过X射线衍射技术和电化学性能测试对Li2Ru1/3Co1/3M1/3O3的微观结构及其电化学性能进行了表征。研究结果表明,Li2Ru1/3Co1/3Ni1/3O3和Li2Ru1/3Co1/3Fe1/3O3为六方层状结构,空间群为R-3M,而Li2Ru1/3Co1/3Mn1/3O3保持了单斜结构;电化学性能测试表明Li2Ru1/3Co1/3Mn1/3O3的电化学性能优于掺杂Fe和Ni的三元材料,该材料具有良好的循环性能,在电流密度为16 m A/g情况下,首次充电容量达到190 m Ah/g,首次放电容量为171 m Ah/g,50次循环后容量保持率为98%。
