Carbon dots(CDs)are functionalized carbon-based nanomaterials that have the potential for use in advanced batteries,owing to their ultrasmall size,tunable surface functional groups and excellent dispersibility.This re...Carbon dots(CDs)are functionalized carbon-based nanomaterials that have the potential for use in advanced batteries,owing to their ultrasmall size,tunable surface functional groups and excellent dispersibility.This review summarizes recent advances in CD-based materials for advanced batteries.Methods for the preparation of CDs are first introduced,focusing on the feasibility of large-scale synthesis,and four critical uses of CDs are analyzed:electrolyte solutions,metal electrode coatings,electrode materials,and solid-state batteries.We then consider how CDs suppress dendrite formation,decrease volume expansion,accelerate charge transfer,and improve ion migration.Finally,existing problems are discussed,including the industrial production of CDs,their role as additives in the evolution of electrode interfaces,and strategies for giving them multifunctionality.展开更多
Na_(2)Ti_(3)O_(7)and Na_(2)Ti_(6)O_(13)are two typical titanate-based sodium-storage materials,featuring the high theoretical capacity and favorable structure stability,respectively.Regulating the ratio of them in the...Na_(2)Ti_(3)O_(7)and Na_(2)Ti_(6)O_(13)are two typical titanate-based sodium-storage materials,featuring the high theoretical capacity and favorable structure stability,respectively.Regulating the ratio of them in the composite material is the key to strengthen its electrochemical characteristics.Herein,based on the high specific surface area and abundant surface functional groups of carbon dots(CDs),sodium titanate precursors containing CDs were in situ prepared by one-step hydrothermal method.After the thermal conversion of the precursors,a composite material(NNTO/C)of Na_(2)Ti_(3)O_(7)and Na_(2)Ti_(6)O_(13)was obtained,containing conductive carbon derived from CDs.The introduc⁃tion of conductive carbon not only adjusts the composition ratio of the mixed phases,but also provides a small charge transfer impedance(Rct,7.48Ω)and a big specific surface area(100.8 m^(2)/g).As a result,NNTO/C composites exhibit better sodium storage behavior while playing the synergistic interaction of mixed phases.When employed as the anode,after 200 cycles at 0.05 A/g,NNTO/C still maintains a specific capacity of 143.8 mA‧h/g.After 400 cycles at 1.00 A/g,the specific capacity remains as high as 108 mA‧h/g.This study suggests an innovative thinking for designing two-phase structures of electrode materials and the greater use of CDs in electrochemical energy storage.展开更多
文摘Carbon dots(CDs)are functionalized carbon-based nanomaterials that have the potential for use in advanced batteries,owing to their ultrasmall size,tunable surface functional groups and excellent dispersibility.This review summarizes recent advances in CD-based materials for advanced batteries.Methods for the preparation of CDs are first introduced,focusing on the feasibility of large-scale synthesis,and four critical uses of CDs are analyzed:electrolyte solutions,metal electrode coatings,electrode materials,and solid-state batteries.We then consider how CDs suppress dendrite formation,decrease volume expansion,accelerate charge transfer,and improve ion migration.Finally,existing problems are discussed,including the industrial production of CDs,their role as additives in the evolution of electrode interfaces,and strategies for giving them multifunctionality.
文摘Na_(2)Ti_(3)O_(7)and Na_(2)Ti_(6)O_(13)are two typical titanate-based sodium-storage materials,featuring the high theoretical capacity and favorable structure stability,respectively.Regulating the ratio of them in the composite material is the key to strengthen its electrochemical characteristics.Herein,based on the high specific surface area and abundant surface functional groups of carbon dots(CDs),sodium titanate precursors containing CDs were in situ prepared by one-step hydrothermal method.After the thermal conversion of the precursors,a composite material(NNTO/C)of Na_(2)Ti_(3)O_(7)and Na_(2)Ti_(6)O_(13)was obtained,containing conductive carbon derived from CDs.The introduc⁃tion of conductive carbon not only adjusts the composition ratio of the mixed phases,but also provides a small charge transfer impedance(Rct,7.48Ω)and a big specific surface area(100.8 m^(2)/g).As a result,NNTO/C composites exhibit better sodium storage behavior while playing the synergistic interaction of mixed phases.When employed as the anode,after 200 cycles at 0.05 A/g,NNTO/C still maintains a specific capacity of 143.8 mA‧h/g.After 400 cycles at 1.00 A/g,the specific capacity remains as high as 108 mA‧h/g.This study suggests an innovative thinking for designing two-phase structures of electrode materials and the greater use of CDs in electrochemical energy storage.
