Mixed-valence is an effective way to achieve high electrochemical performance of anodes for supercapacitor.However,inordinate mixed valence with more structural defects leads to structural instability.The development ...Mixed-valence is an effective way to achieve high electrochemical performance of anodes for supercapacitor.However,inordinate mixed valence with more structural defects leads to structural instability.The development of mixed valence electrodes that can maintain a stable structure during the defect formation process is the key to resolving this problem.Cu_(2-x)Se with mixed-valence is a potential candidate,the stable monoclinic structure of Cu2Se can be transformed into another stable cubic structure(x>0.15).Herein,Cu_(1.85)Se anode with mixed valence reveals the ultrahigh specific capacity of 247.8 mA·h/g at 2 A/g.Furthermore,the introduction of multi-walled carbon nanotubes(MWCNTs)into Cu1.85Se further improves the specific capacity(435 mA·h/g at 2 A/g).XRD shows that the introduction of MWCNTs can improve the reversibility via chemical interactions and accelerate the electron transfer in the Cu1.85Se/MWCNTs.Notably,the assembled symmetric supercapacitor(SC)device expresses a high energy density of 41.4 W·h/kg,and the capacity remains 83%even after 8000 charge/discharge cycles.This research demonstrates the great potential of developing high specific capacity anode materials for superior performance supercapacitor.展开更多
基金The work is funded by the subproject of the National Key Research and Development Program of China(2017YFC0602102)the Department of Science and Technology of Sichuan Province(2021JDTD0030)+1 种基金the National Natural Science Foundation of China(No.U20A20213,61727818,51874184)the Chengdu Science and Technology Project(2020-GH02-0065-HZ)。
文摘Mixed-valence is an effective way to achieve high electrochemical performance of anodes for supercapacitor.However,inordinate mixed valence with more structural defects leads to structural instability.The development of mixed valence electrodes that can maintain a stable structure during the defect formation process is the key to resolving this problem.Cu_(2-x)Se with mixed-valence is a potential candidate,the stable monoclinic structure of Cu2Se can be transformed into another stable cubic structure(x>0.15).Herein,Cu_(1.85)Se anode with mixed valence reveals the ultrahigh specific capacity of 247.8 mA·h/g at 2 A/g.Furthermore,the introduction of multi-walled carbon nanotubes(MWCNTs)into Cu1.85Se further improves the specific capacity(435 mA·h/g at 2 A/g).XRD shows that the introduction of MWCNTs can improve the reversibility via chemical interactions and accelerate the electron transfer in the Cu1.85Se/MWCNTs.Notably,the assembled symmetric supercapacitor(SC)device expresses a high energy density of 41.4 W·h/kg,and the capacity remains 83%even after 8000 charge/discharge cycles.This research demonstrates the great potential of developing high specific capacity anode materials for superior performance supercapacitor.
