Rechargeable lithium-sulfur(Li-S)batteries have attracted significant research attention due to their high capacity and energy density.However,their commercial applications are still hindered by challenges such as the...Rechargeable lithium-sulfur(Li-S)batteries have attracted significant research attention due to their high capacity and energy density.However,their commercial applications are still hindered by challenges such as the shuttle effect of soluble lithium sulfide species,the insulating nature of sulfur,and the fast capacity decay of the electrodes.Various efforts are devoted to address these problems through questing more conductive hosts with abundant polysulfide chemisorption sites,as well as modifying the separators to physically/chemically retard the polysulfides migration.Two dimensional transition metal carbides,carbonitrides and nitrides,so-called MXenes,are ideal for confining the polysulfides shuttling effects due to their high conductivity,layered structure as well as rich surface terminations.As such,MXenes have thus been widely studied in Li-S batteries,focusing on the conductive sulfur hosts,polysulfides interfaces,and separators.Therefore,in this review,we summarize the significant progresses regarding the design of multifunctional MXene-based Li-S batteries and discuss the solutions for improving electrochemical performances in detail.In addition,challenges and perspectives of MXenes for Li-S batteries are also outlined.展开更多
Lithium-ion batteries(LIBs)have been widely applied in portable electronic devices and electric vehicles.With the booming of the respective markets,a huge quantity of spent LIBs that typically use either LiFePO_(4) or...Lithium-ion batteries(LIBs)have been widely applied in portable electronic devices and electric vehicles.With the booming of the respective markets,a huge quantity of spent LIBs that typically use either LiFePO_(4) or Li N_(x)Co_(y)Mn_(z)O_(2) cathode materials will be produced in the very near future,imposing significant pressure for the development of suitable disposal/recycling technologies,in terms of both environmental protection and resource reclaiming.In this review,we firstly do a comprehensive summary of the-state-of-art technologies to recycle Li N_(x)Co_(y)Mn_(z)O_(2) and LiFePO_(4)-based LIBs,in the aspects of pretreatment,hydrometallurgical recycling,and direct regeneration of the cathode materials.This closed-loop strategy for cycling cathode materials has been regarded as an ideal approach considering its economic benefit and environmental friendliness.Afterward,as for the exhausted anode materials,we focus on the utilization of exhausted anode materials to obtain other functional materials,such as graphene.Finally,the existing challenges in recycling the LiFePO_(4) and Li N_(x)Co_(y)Mn_(z)O_(2) cathodes and graphite anodes for industrial-scale application are discussed in detail;and the possible strategies for these issues are proposed.We expect this review can provide a roadmap towards better technologies for recycling LIBs,shed light on the future development of novel battery recycling technologies to promote the environmental benignity and economic viability of the battery industry and pave way for the large-scale application of LIBs in industrial fields in the near future.展开更多
There is a growing demand for hybrid supercapacitor systems to overcome the energy density limitation of existing-generation electric double layer capacitors （EDLCs）, leading to next generation-Ⅱ supercapacitors wi...There is a growing demand for hybrid supercapacitor systems to overcome the energy density limitation of existing-generation electric double layer capacitors （EDLCs）, leading to next generation-Ⅱ supercapacitors with minimum sacrifice in power density and cycle life. Here, an advanced graphene-based hybrid system, consisting of a graphene-inserted Li4Ti5O12 （LTO） composite anode （G-LTO） and a three-dimensional porous graphene-sucrose cathode, has been fabricated for the purpose of combining both the benefits of Li-ion batteries （energy source） and supercapacitors （power source）. Graphene-based materials play a vital role in both electrodes in respect of the high performance of the hybrid supercapacitor. For example, compared with the theoretical capacity of 175 mA-h.g-1 for pure LTO, the G-LTO nanocomposite delivered excellent reversible capacities of 207, 190, and 176 mA·1h·g-1 at rates of 0.3, 0.5, and 1 C, respectively, in the potential range 1.0-2.5 V vs. Li/Li＋; these are among the highest values for LTO-based nano- composites at the same rates and potential range. Based on this, an optimized hybrid supercapacitor was fabricated following the standard industry procedure; this displayed an ultrahigh energy density of 95 Wh·kg-1 at a rate of 0.4 C （2.5 h） over a wide voltage range （0-3 V）, and still retained an energy density of 32 Wh·kg-1 at a high rate of up to 100 C, equivalent to a full discharge in 36 s, which is exceptionally fast for hybrid supercapacitors. The excellent performance of this Li-ion hybrid supercapacitor indicates that graphene-based materials may indeed play a significant role in next-generation supercapacitors with excellent electrochemical performance.展开更多
The practical application of the lithium anode in lithium metal batteries(LMBs) has been hindered by the uncontrollable growth of lithium dendrite and the high volumetric change during cycling. Herein, the in situ for...The practical application of the lithium anode in lithium metal batteries(LMBs) has been hindered by the uncontrollable growth of lithium dendrite and the high volumetric change during cycling. Herein, the in situ formed three-dimensional(3D) lithium-boron(Li-B) alloy is suggested as an excellent alternative to the Li metal, in which the 3D Li B skeleton can mitigate the growth of Li dendrites and volumetric change. In this study, the Li-B alloy anodes with different B contents were manufactured by high-temperature melting. It was found that the boron content had a significant effect on the electrochemical performance of the Li-B alloy. The Li-B alloy with the least B content(10 wt%, 10LiB) demonstrated the lowest overpotential of 0.0852 V after 300 h and the lowest interface resistance. However, the full cell with 15LiB as the anode displayed the best cycling performance of 115 m Ah·g^(-1) after 100 cycles with a columbic efficiency greater than 97%. The obtained results suggest that the in situ formed three-dimensional Li-B alloy anode can be an excellent alternative to the Li anode via tuning B contents for next-generation high energy density LMBs.展开更多
Li-S battery has attracted great attention due to its high specific capacity and energy density.However,the serious polysulfides shuttle effect,low conductivity of sulfur and discharge product of lithium sulfide limit...Li-S battery has attracted great attention due to its high specific capacity and energy density.However,the serious polysulfides shuttle effect,low conductivity of sulfur and discharge product of lithium sulfide limit their application in commercial energy storage system.To solve the above problems,this work designs and constructs C@CoSe_(2) nano wire material as sulfur host for realizing high-performance Li-S battery.By combing the high conductivity,strong chemisorption,promising catalytic capacity and unique nanowire array structure,the C@CoSe_(2)/S electrode demonstrates a high specific capacity of 1264 mAh·g^(-1) with a low capacity decay of 0.051%per cycle at 0.2 C over 200 cycles.As expected,the battery delivers outstanding capacity retention over 1000 cycles at5 C and the decay is as low as≈0.026% per cycle.Moreover,even at higher sulfur loading of 5.1 mg·cm^(-2),the battery could still remain a stable areal capacity of 5.02 mAh·cm^(-2) at 0.2 C. More importantly,the experimental data and theoretical calculation results reveal that the internal mechanism of the improved electrochemical performance is the catalytic activation of CoSe_(2) on poly sulfides.展开更多
The world's energy system is changing dramatically.Li-ion battery,as a powerful and highly effective energy storage technique,is crucial to the new energy revolution for its continuously expanding application in e...The world's energy system is changing dramatically.Li-ion battery,as a powerful and highly effective energy storage technique,is crucial to the new energy revolution for its continuously expanding application in electric vehicles and grids.Over the entire lifetime of these power batteries,it is essential to monitor their state of health not only for the predicted mileage and safety management of the running electric vehicles,but also for an"end-of-life"evaluation for their repurpose.Electrochemical impedance spectroscopy(EIS)has been widely used to diagnose the health state of batteries quickly and nondestructively.In this review,we have outlined the working principles of several electrochemical impedance techniques and further evaluated their application prospects to achieve the goal of nondestructive testing of battery health.EIS can scientifically and reasonably perform real-time monitoring and evaluation of electric vehicle power batteries in the future and play an important role in vehicle safety and battery gradient utilization.展开更多
We report a hybrid nanogenerator that includes a triboelectric nanogenerator （TENG） and an electromagnetic generator （EMG） for scavenging mechanical energy. This nanogenerator operates in a hybrid mode using both ...We report a hybrid nanogenerator that includes a triboelectric nanogenerator （TENG） and an electromagnetic generator （EMG） for scavenging mechanical energy. This nanogenerator operates in a hybrid mode using both the triboelectric and electromagnetic induction effects. Under a vibration frequency of 14 Hz, the fabricated TENG can deliver an open-circuit voltage of about 84 V, a short-circuit current of 43 μA, and a maximum power of 1.2 mW （the corresponding power per unit mass and volume are 1.82 mW/g and 3.4 W/m^3, respectively） under a loading resistance of 2 MΩ, whereas the fabricated EMG can produce an opencircuit voltage of about 9.9 V, a short-circuit current of 7 mA, and a maximum power of 17.4 mW （the corresponding power per unit mass and volume are 0.53 mW/g and 3.7 W/m^3, respectively） under a loading resistance of 2 kΩ. Impedance matching between the TENG and EMG can be achieved using a transformer to decrease the impedance of the TENG. Moreover, the energy produced by the hybrid nanogenerator can be stored in a home-made Li-ion battery. This research represents important progress toward practical applications of vibration energy generation for realizing self-charging power cells.展开更多
The practical application of solid polymer electrolytes in high-energy Li metal batteries is hindered by Li dendrites,electrochemical instability and insufficient ion conductance.To address these issues,flexible compo...The practical application of solid polymer electrolytes in high-energy Li metal batteries is hindered by Li dendrites,electrochemical instability and insufficient ion conductance.To address these issues,flexible composite polymer electrolyte(CPE)membranes with three dimensional(3D)aramid nanofiber(ANF)frameworks are facilely fabricated by filling polyethylene oxide(PEO)-lithium bis(trifluoromethylsulphonyl)imide(Li TFSI)electrolyte into 3D ANF scaffolds.Because of the unique composite structure design and the continuous ion conduction at the 3D ANF framework/PEO-Li TFSI interfaces,the CPE membranes show higher mechanical strength(10.0 MPa),thermostability,electrochemical stability(4.6 V at 60℃)and ionic conductivity than the pristine PEO-Li TFSI electrolyte.Thus,the CPEs display greatly improved interfacial stability against Li dendrites(≥1000 h at 30℃under 0.10 m A cm-2),compared with the pristine electrolyte(short circuit in 13 h).The CPE-based all-solid-state LiFePO4/Li cells also exhibit superior cycling performance(e.g.,130 mA h g-1 with 93%retention after 100 cycles at 0.4 C)than the ANF-free cells(e.g.,82 mA h g-1 with 66%retention).This work offers a simple and effective way to achieve high-performance composite electrolyte membranes with 3D nanofiller framework for promising solid-state Li metal battery applications.展开更多
Lithium(Li)metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries.However,the practical implementation of Li anode has been hindered by...Lithium(Li)metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries.However,the practical implementation of Li anode has been hindered by dendritic growth and volume expansion during cycling,which results in low Coulombic efficiency(CE),short lifespan,and safety hazards.Here,we report a highly stable and dendrite-free Li metal anode by utilizing N-doped hollow porous bowl-like hard carbon/reduced graphene nanosheets(CB@rGO)hybrids as three-dimensional(3D)conductive and lithiophilic scaffold host.The lithiophilic carbon bowl(CB)mainly works as excellent guides during the Li plating process,whereas the rGO layer with high conductivity and mechanical stability maintains the integrity of the composite by confining the volume change in long-range order during cycling.Moreover,the local current density can be reduced due to the 3D conductive framework.Therefore,CB@rGO presents a low lithium metal nucleation overpotential of 18 mV,high CE of 98%,and stable cycling without obvious voltage fluctuation for over 600 cycles at a current density of 1 mA cm^(-2).Our study not only provides a good CB@rGO host and pre-Lithiated CB@rGO composite anode electrode,but also brings a new strategy of designing 3D electrodes for those active materials suffering from severe volume expansion.展开更多
[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating propertie...[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating properties as well as good electrochemical performance as the anode for Li-ion batteries. The formation of the nanobelts results from a precipitation-dissolution-transformation mechanism, and the [020] oriented growth can be ascribed to the {010} facet family having the lowest atomic density. In particular, SnS shows clear Li-Sn alloying/de-alloying reversible reactions in the potential range 0.1-1.0 V. Based on galvanostatic measurements and electrochemical impedance spectroscopy, SnS nanobelts have shown impressive rate performance. The post-cycled SnS nanobelts were completely transformed into metallic tin, and preserved the one-dimensional structure due to their flexibility which accommodates the large volumetric expansion.展开更多
基金the support from an Empa interal research grant.
文摘Rechargeable lithium-sulfur(Li-S)batteries have attracted significant research attention due to their high capacity and energy density.However,their commercial applications are still hindered by challenges such as the shuttle effect of soluble lithium sulfide species,the insulating nature of sulfur,and the fast capacity decay of the electrodes.Various efforts are devoted to address these problems through questing more conductive hosts with abundant polysulfide chemisorption sites,as well as modifying the separators to physically/chemically retard the polysulfides migration.Two dimensional transition metal carbides,carbonitrides and nitrides,so-called MXenes,are ideal for confining the polysulfides shuttling effects due to their high conductivity,layered structure as well as rich surface terminations.As such,MXenes have thus been widely studied in Li-S batteries,focusing on the conductive sulfur hosts,polysulfides interfaces,and separators.Therefore,in this review,we summarize the significant progresses regarding the design of multifunctional MXene-based Li-S batteries and discuss the solutions for improving electrochemical performances in detail.In addition,challenges and perspectives of MXenes for Li-S batteries are also outlined.
基金supported by the National Natural Science Foundation of China(Nos.51072130,51502045 and 21905202)the Australian Research Council(ARC)through Discovery Early Career Researcher Award(DECRA,No.DE170100871)program。
文摘Lithium-ion batteries(LIBs)have been widely applied in portable electronic devices and electric vehicles.With the booming of the respective markets,a huge quantity of spent LIBs that typically use either LiFePO_(4) or Li N_(x)Co_(y)Mn_(z)O_(2) cathode materials will be produced in the very near future,imposing significant pressure for the development of suitable disposal/recycling technologies,in terms of both environmental protection and resource reclaiming.In this review,we firstly do a comprehensive summary of the-state-of-art technologies to recycle Li N_(x)Co_(y)Mn_(z)O_(2) and LiFePO_(4)-based LIBs,in the aspects of pretreatment,hydrometallurgical recycling,and direct regeneration of the cathode materials.This closed-loop strategy for cycling cathode materials has been regarded as an ideal approach considering its economic benefit and environmental friendliness.Afterward,as for the exhausted anode materials,we focus on the utilization of exhausted anode materials to obtain other functional materials,such as graphene.Finally,the existing challenges in recycling the LiFePO_(4) and Li N_(x)Co_(y)Mn_(z)O_(2) cathodes and graphite anodes for industrial-scale application are discussed in detail;and the possible strategies for these issues are proposed.We expect this review can provide a roadmap towards better technologies for recycling LIBs,shed light on the future development of novel battery recycling technologies to promote the environmental benignity and economic viability of the battery industry and pave way for the large-scale application of LIBs in industrial fields in the near future.
基金The authors gratefully acknowledge financial support from Ministry of Science and Technology of the People＇s Republic of China （MOST） （Grants Nos. 2012CB933401 and 2011DFB50300）, and National Natural Science Foundation of China （NSFC） （Grants Nos. 50933003 and 51273093）.
文摘There is a growing demand for hybrid supercapacitor systems to overcome the energy density limitation of existing-generation electric double layer capacitors （EDLCs）, leading to next generation-Ⅱ supercapacitors with minimum sacrifice in power density and cycle life. Here, an advanced graphene-based hybrid system, consisting of a graphene-inserted Li4Ti5O12 （LTO） composite anode （G-LTO） and a three-dimensional porous graphene-sucrose cathode, has been fabricated for the purpose of combining both the benefits of Li-ion batteries （energy source） and supercapacitors （power source）. Graphene-based materials play a vital role in both electrodes in respect of the high performance of the hybrid supercapacitor. For example, compared with the theoretical capacity of 175 mA-h.g-1 for pure LTO, the G-LTO nanocomposite delivered excellent reversible capacities of 207, 190, and 176 mA·1h·g-1 at rates of 0.3, 0.5, and 1 C, respectively, in the potential range 1.0-2.5 V vs. Li/Li＋; these are among the highest values for LTO-based nano- composites at the same rates and potential range. Based on this, an optimized hybrid supercapacitor was fabricated following the standard industry procedure; this displayed an ultrahigh energy density of 95 Wh·kg-1 at a rate of 0.4 C （2.5 h） over a wide voltage range （0-3 V）, and still retained an energy density of 32 Wh·kg-1 at a high rate of up to 100 C, equivalent to a full discharge in 36 s, which is exceptionally fast for hybrid supercapacitors. The excellent performance of this Li-ion hybrid supercapacitor indicates that graphene-based materials may indeed play a significant role in next-generation supercapacitors with excellent electrochemical performance.
基金financially supported by the National Natural Science Foundation of China (Nos. U1904216 and51771236)the Science Fund for Distinguished Young Scholars of Hunan Province (No. 2018JJ1038)+1 种基金the Innovation-Driven Project of Central South University (No. 2020CX007)the State Key Laboratory of Powder Metallurgy, Central South University。
文摘The practical application of the lithium anode in lithium metal batteries(LMBs) has been hindered by the uncontrollable growth of lithium dendrite and the high volumetric change during cycling. Herein, the in situ formed three-dimensional(3D) lithium-boron(Li-B) alloy is suggested as an excellent alternative to the Li metal, in which the 3D Li B skeleton can mitigate the growth of Li dendrites and volumetric change. In this study, the Li-B alloy anodes with different B contents were manufactured by high-temperature melting. It was found that the boron content had a significant effect on the electrochemical performance of the Li-B alloy. The Li-B alloy with the least B content(10 wt%, 10LiB) demonstrated the lowest overpotential of 0.0852 V after 300 h and the lowest interface resistance. However, the full cell with 15LiB as the anode displayed the best cycling performance of 115 m Ah·g^(-1) after 100 cycles with a columbic efficiency greater than 97%. The obtained results suggest that the in situ formed three-dimensional Li-B alloy anode can be an excellent alternative to the Li anode via tuning B contents for next-generation high energy density LMBs.
基金financially supported by the Natural Science Foundation of Heilongjiang Province(No.LH2020B008)the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.2019DX13)+1 种基金China Postdoctoral Science Foundation(Nos.2016M600253 and 2017T100246)the Post-doctoral Foundation of Heilongjiang Province(No.LBH-Z16060)。
文摘Li-S battery has attracted great attention due to its high specific capacity and energy density.However,the serious polysulfides shuttle effect,low conductivity of sulfur and discharge product of lithium sulfide limit their application in commercial energy storage system.To solve the above problems,this work designs and constructs C@CoSe_(2) nano wire material as sulfur host for realizing high-performance Li-S battery.By combing the high conductivity,strong chemisorption,promising catalytic capacity and unique nanowire array structure,the C@CoSe_(2)/S electrode demonstrates a high specific capacity of 1264 mAh·g^(-1) with a low capacity decay of 0.051%per cycle at 0.2 C over 200 cycles.As expected,the battery delivers outstanding capacity retention over 1000 cycles at5 C and the decay is as low as≈0.026% per cycle.Moreover,even at higher sulfur loading of 5.1 mg·cm^(-2),the battery could still remain a stable areal capacity of 5.02 mAh·cm^(-2) at 0.2 C. More importantly,the experimental data and theoretical calculation results reveal that the internal mechanism of the improved electrochemical performance is the catalytic activation of CoSe_(2) on poly sulfides.
基金financially supported by the State Grid Corporation Science and Technology Project of China(No.520940180017)。
文摘The world's energy system is changing dramatically.Li-ion battery,as a powerful and highly effective energy storage technique,is crucial to the new energy revolution for its continuously expanding application in electric vehicles and grids.Over the entire lifetime of these power batteries,it is essential to monitor their state of health not only for the predicted mileage and safety management of the running electric vehicles,but also for an"end-of-life"evaluation for their repurpose.Electrochemical impedance spectroscopy(EIS)has been widely used to diagnose the health state of batteries quickly and nondestructively.In this review,we have outlined the working principles of several electrochemical impedance techniques and further evaluated their application prospects to achieve the goal of nondestructive testing of battery health.EIS can scientifically and reasonably perform real-time monitoring and evaluation of electric vehicle power batteries in the future and play an important role in vehicle safety and battery gradient utilization.
基金This work was supported by Beijing Natural Science Foundation （No. 2154059）, National Natural Science Foundation of China （Nos. 51472055 and 61404034）, and the ＂Thousands Talents＂ program for pioneer researcher and his innovation team, China.
文摘We report a hybrid nanogenerator that includes a triboelectric nanogenerator （TENG） and an electromagnetic generator （EMG） for scavenging mechanical energy. This nanogenerator operates in a hybrid mode using both the triboelectric and electromagnetic induction effects. Under a vibration frequency of 14 Hz, the fabricated TENG can deliver an open-circuit voltage of about 84 V, a short-circuit current of 43 μA, and a maximum power of 1.2 mW （the corresponding power per unit mass and volume are 1.82 mW/g and 3.4 W/m^3, respectively） under a loading resistance of 2 MΩ, whereas the fabricated EMG can produce an opencircuit voltage of about 9.9 V, a short-circuit current of 7 mA, and a maximum power of 17.4 mW （the corresponding power per unit mass and volume are 0.53 mW/g and 3.7 W/m^3, respectively） under a loading resistance of 2 kΩ. Impedance matching between the TENG and EMG can be achieved using a transformer to decrease the impedance of the TENG. Moreover, the energy produced by the hybrid nanogenerator can be stored in a home-made Li-ion battery. This research represents important progress toward practical applications of vibration energy generation for realizing self-charging power cells.
基金supported partially by Beijing Natural Science Foundation(L172036)Joint Funds of the Equipment Pre-Research and Ministry of Education(6141A020225)+2 种基金Par-Eu Scholars Program,Science and Technology Beijing 100 Leading Talent Training Project,Beijing Municipal Science and Technology Project(Z161100002616039)China Postdoctoral Science Foundation(2018M631419)the Fundamental Research Funds for the Central Universities(2017ZZD02 and 2019QN001).
文摘The practical application of solid polymer electrolytes in high-energy Li metal batteries is hindered by Li dendrites,electrochemical instability and insufficient ion conductance.To address these issues,flexible composite polymer electrolyte(CPE)membranes with three dimensional(3D)aramid nanofiber(ANF)frameworks are facilely fabricated by filling polyethylene oxide(PEO)-lithium bis(trifluoromethylsulphonyl)imide(Li TFSI)electrolyte into 3D ANF scaffolds.Because of the unique composite structure design and the continuous ion conduction at the 3D ANF framework/PEO-Li TFSI interfaces,the CPE membranes show higher mechanical strength(10.0 MPa),thermostability,electrochemical stability(4.6 V at 60℃)and ionic conductivity than the pristine PEO-Li TFSI electrolyte.Thus,the CPEs display greatly improved interfacial stability against Li dendrites(≥1000 h at 30℃under 0.10 m A cm-2),compared with the pristine electrolyte(short circuit in 13 h).The CPE-based all-solid-state LiFePO4/Li cells also exhibit superior cycling performance(e.g.,130 mA h g-1 with 93%retention after 100 cycles at 0.4 C)than the ANF-free cells(e.g.,82 mA h g-1 with 66%retention).This work offers a simple and effective way to achieve high-performance composite electrolyte membranes with 3D nanofiller framework for promising solid-state Li metal battery applications.
基金supported by the National Natural Science Foundation of China(Nos.52072323 and 51872098)the“Double-First Class”Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen University,as well as Postdoctoral Foundation of China(2018M632929).
文摘Lithium(Li)metal with high theoretical capacity and low electrochemical potential is the most ideal anode for next-generation high-energy batteries.However,the practical implementation of Li anode has been hindered by dendritic growth and volume expansion during cycling,which results in low Coulombic efficiency(CE),short lifespan,and safety hazards.Here,we report a highly stable and dendrite-free Li metal anode by utilizing N-doped hollow porous bowl-like hard carbon/reduced graphene nanosheets(CB@rGO)hybrids as three-dimensional(3D)conductive and lithiophilic scaffold host.The lithiophilic carbon bowl(CB)mainly works as excellent guides during the Li plating process,whereas the rGO layer with high conductivity and mechanical stability maintains the integrity of the composite by confining the volume change in long-range order during cycling.Moreover,the local current density can be reduced due to the 3D conductive framework.Therefore,CB@rGO presents a low lithium metal nucleation overpotential of 18 mV,high CE of 98%,and stable cycling without obvious voltage fluctuation for over 600 cycles at a current density of 1 mA cm^(-2).Our study not only provides a good CB@rGO host and pre-Lithiated CB@rGO composite anode electrode,but also brings a new strategy of designing 3D electrodes for those active materials suffering from severe volume expansion.
基金Acknowledgements This work was supported by the State Key Project of Fundamental Research for Nanoscience and Nano- technology （Nos. 2011CB932401 and 2011CBA00500）, and the National Natural Science Foundation of China （Nos. 20921001 and 21051001）. We are grateful to Associate Professor Jiaping Wang and lab assistant Fei Zhao in the Tsinghua-Foxconn Nanocenter for their generous help in the fabrication of batteries.
文摘[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating properties as well as good electrochemical performance as the anode for Li-ion batteries. The formation of the nanobelts results from a precipitation-dissolution-transformation mechanism, and the [020] oriented growth can be ascribed to the {010} facet family having the lowest atomic density. In particular, SnS shows clear Li-Sn alloying/de-alloying reversible reactions in the potential range 0.1-1.0 V. Based on galvanostatic measurements and electrochemical impedance spectroscopy, SnS nanobelts have shown impressive rate performance. The post-cycled SnS nanobelts were completely transformed into metallic tin, and preserved the one-dimensional structure due to their flexibility which accommodates the large volumetric expansion.
