The graphene/mesocarbon microbead(MCMB)composite is assessed as an anode material with a high capacity for lithium-ion batteries.The composite electrode exhibits improved cycling stability and rate capability,deliveri...The graphene/mesocarbon microbead(MCMB)composite is assessed as an anode material with a high capacity for lithium-ion batteries.The composite electrode exhibits improved cycling stability and rate capability,delivering a high initial charge/discharge capacity of 421.4 mA·h/g/494.8 mA·h/g as well as an excellent capacity retention over 500 cycles at a current density of 40 mA/g.At a higher current density of 800 mA/g,the electrode still retains 35%of its initial capacity which exceeds the capacity retention of pure graphene or MCMB reference electrodes.Cyclic voltammetry and electrochemical impedance spectroscopy reveal that the composite electrode favors electrochemical kinetics as compared with graphene and MCMB separately.Superior electrochemical properties suggest a strong synergetic effect between highly conductive graphene and MCMB.展开更多
Anode materials for Li-ion batteries(LIBs)utilized in electric vehicles,portable electronics,and other devices are mainly graphite(Gr)and its derivatives.However,the limited energy density of Gr-based anodes promotes ...Anode materials for Li-ion batteries(LIBs)utilized in electric vehicles,portable electronics,and other devices are mainly graphite(Gr)and its derivatives.However,the limited energy density of Gr-based anodes promotes the exploration of alternative anode materials such as silicon(Si)-based materials because of their abundance in nature and low cost.Specifically,Si can store 10 times more energy than Gr and also has the potential to enhance the energy density of LIBs.Despite the many advantages of Si-based anodes,such as high theoretical capacity and low price,their widespread use is hindered by two major issues:charge-induced volume expansion and unreliable solid electrolyte interphase(SEI)propagation.In this detailed review,we highlight the key issues,current advances,and prospects in the rational design of Si-based electrodes for practical applications.We first explain the fundamental electrochemistry of Si and the importance of Si-based anodes in LIBs.The excessive volume increase,relatively low charge efficiency,and inadequate areal capacity of Si-based anodes are discussed to identify the barriers in enhancing their performance in LIBs.Subsequently,the use of binders(e.g.,linear polymer binders,branched polymer binders,cross-linked polymer binders,and conjugated conductive polymer binders),material-based anode composites(such as carbon and its derivatives,metal oxides,and MXenes),and liquid electrolyte construction techniques are highlighted to overcome the identified barriers.Further,tailoring Si-based materials and reshaping their surfaces and interfaces,including improving binders and electrolytes,are shown to be viable approaches to address their drawbacks,such as volume expansion,low charge efficiency,and poor areal capacity.Finally,we highlight that research and development on Si-based anodes are indispensable for their use in commercial applications.展开更多
基金Project supported by the National Natural Science Foundation of China(No.21573239)the Guangdong Provincial Project for Science and Technology(Nos.2014TX01N14,2015B010135008,and 2016B010114003)+1 种基金the Guangzhou Municipal Project for Science and Technology(No.201509010018)the K.C.WONG Education Foundation,China。
文摘The graphene/mesocarbon microbead(MCMB)composite is assessed as an anode material with a high capacity for lithium-ion batteries.The composite electrode exhibits improved cycling stability and rate capability,delivering a high initial charge/discharge capacity of 421.4 mA·h/g/494.8 mA·h/g as well as an excellent capacity retention over 500 cycles at a current density of 40 mA/g.At a higher current density of 800 mA/g,the electrode still retains 35%of its initial capacity which exceeds the capacity retention of pure graphene or MCMB reference electrodes.Cyclic voltammetry and electrochemical impedance spectroscopy reveal that the composite electrode favors electrochemical kinetics as compared with graphene and MCMB separately.Superior electrochemical properties suggest a strong synergetic effect between highly conductive graphene and MCMB.
基金supported by the Fundamental Research Funds for the Central Universities(No.2232023D-02,2232023Y-01,and 2232021A-02)the National Natural Science Foundation of China(No.52202361,No.92163121,and No.52122312).
文摘Anode materials for Li-ion batteries(LIBs)utilized in electric vehicles,portable electronics,and other devices are mainly graphite(Gr)and its derivatives.However,the limited energy density of Gr-based anodes promotes the exploration of alternative anode materials such as silicon(Si)-based materials because of their abundance in nature and low cost.Specifically,Si can store 10 times more energy than Gr and also has the potential to enhance the energy density of LIBs.Despite the many advantages of Si-based anodes,such as high theoretical capacity and low price,their widespread use is hindered by two major issues:charge-induced volume expansion and unreliable solid electrolyte interphase(SEI)propagation.In this detailed review,we highlight the key issues,current advances,and prospects in the rational design of Si-based electrodes for practical applications.We first explain the fundamental electrochemistry of Si and the importance of Si-based anodes in LIBs.The excessive volume increase,relatively low charge efficiency,and inadequate areal capacity of Si-based anodes are discussed to identify the barriers in enhancing their performance in LIBs.Subsequently,the use of binders(e.g.,linear polymer binders,branched polymer binders,cross-linked polymer binders,and conjugated conductive polymer binders),material-based anode composites(such as carbon and its derivatives,metal oxides,and MXenes),and liquid electrolyte construction techniques are highlighted to overcome the identified barriers.Further,tailoring Si-based materials and reshaping their surfaces and interfaces,including improving binders and electrolytes,are shown to be viable approaches to address their drawbacks,such as volume expansion,low charge efficiency,and poor areal capacity.Finally,we highlight that research and development on Si-based anodes are indispensable for their use in commercial applications.
