超级电容器
化学
过电位
交换电流密度
电催化剂
镍
塔菲尔方程
双功能
无机化学
钴
电极
电化学
锰
硫化钴
电解质
化学工程
催化作用
物理化学
有机化学
工程类
作者
Hui Xu,Siyao Li,Yuanqiang Zhu,Pengdong Chen,Yong Chen,Xiuqin Kong
标识
DOI:10.1016/j.jelechem.2024.118048
摘要
The development of active electrode materials with dual functions of energy storage and electrocatalyst is important for future energy storage and energy conversion devices. In this work, manganese-doped nickel cobalt sulfide (Mn-NCS) mesoporous microspheres were prepared via a simple two-step solvent-thermal method and the effects of different Mn2+ doping levels on the electrochemical properties and hydrogen evolution reactions (HER) of the prepared samples were investigated. As a supercapacitor electrode material, optimized Mn0.5-NCS had a maximum specific capacitance of 1175C g−1 at a current density of 1 A/g and remained an outstanding capacitance retention rate of 81 % at a current density of 20 A/g. The asymmetric supercapacitor was assembled with the optimal electrode material as the positive electrode and activated carbon as the negative electrode, and a high energy density of 55.4Wh kg−1 was achieved at a power density of 797 W kg−1. The Mn0.5-NCS exhibited the best HER performance in alkaline electrolyte, shown as the lowest overpotential of 95 mV and the smallest Tafel slope of 71 mV dec−1 at a current density of 10 mA cm−2. Experimental tests and density functional theory (DFT) calculations revealed that manganese preferentially occupies nickel sites and acted as an electron donor in the electrochemical process to realize the electron redistribution, increasing electron density and accelerating charge transfer. The results indicated that manganese-doped nickel–cobalt sulfides have great potential as bifunctional electrode materials for high-performance supercapacitors and HER.
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