摘要
开发高比容量和宽电压的负极材料是提升准固态非对称超级电容器能量密度的有效途径之一。本工作借助水热反应及其产物与氨气的相互作用,在碳纤维布表面构筑了氮掺杂无定形氧化钒纳米片阵列。与未掺杂的无定形氧化钒相比,氮掺杂后的电极材料在-0.9~0 V电势窗口下,比容量高达432.2 F/g;在电流密度为10 A/g时,比容量仍然保持203.3 F/g,且表现出优异的循环稳定性。进一步将该负极与MnO2@CC正极和PVA-LiCl凝胶隔膜组装成准固态非对称超级电容器,在475 W/kg的功率密度下,能量密度高达50.5 W·h/kg。所制备电极材料优异的电化学性能主要归因于其独特的结构,具体为:无定形化可以使得氧化钒暴露更多表面反应活性位,而氮元素掺杂能大幅度地提高无定形氧化钒的本征电导率,从而减少了电化学过程中的极化,显著提升比电容量和反应动力学。
The development of anode materials with high specific capacitance and wide voltage is a valid approach to increase the energy density of quasi-solid asymmetric supercapacitors.Herein,nitrogen-doped amorphous vanadium oxide arrays are constructed on the surface of a carbon cloth by means of the hydrothermal reaction and subsequent interaction with ammonia.Compared with the undoped one,the nitrogen-doped amorphous vanadium oxide delivers a high specific capacitance of 432.2 F·g^(−1) at−0.9~0 V with an excellent cycling stability and maintains a value of 203.3 F·g^(−1) when the current density increases to 10 A·g^(−1).When assembling into a quasi-solid asymmetric supercapacitor with a MnO2@CC positive-electrode and PVA/LiCl gelelectrolyte membrane,the device shows a remarkably improved energy density of 50.5 W·h·kg^(−1) at a power density of 475 W·kg^(−1).The excellent electrochemical performance can be mainly attributed to its unique nanostructure.The amorphization induces vanadium oxide to expose more reactive sites,whereas nitrogen doping greatly improves the intrinsic conductivity with reduced polarization during the electrochemical process,hence significantly enhancing the specific capacitance and reaction kinetics.
作者
陈帅
陈灵
江浩
CHEN Shuai;CHEN Ling;JIANG Hao(Key Laboratory for Ultrafine Materials of Ministry of Education,School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2021年第3期945-951,共7页
Energy Storage Science and Technology
基金
国家自然科学基金项目(21975074)。
关键词
氮掺杂
氧化钒
准固态
超级电容器
nitrogen doping
vanadium oxide
quasi-solid
supercapacitors
