Dual-Phase Coexistence Design and Advanced Electrochemical Performance of Cu<sub>2</sub>MoS<sub>4</sub> Electrode Materials for Supercapacitor Application
Ren Hao Xu, Pianpian Ma, Guan Fu Liu, Yin Qiao, Rui Yang Hu, Li Yuan Liu, Müslüm Demir, Guohua Jiang
Abstract
The tetragonal layered transition metal copper–molybdenum sulfide Cu 2 MoS 4 (CMS) possesses a high theoretical electrochemical potential because of its abundant redox properties and large layered surface area, which is favorable for ion adsorption/desorption and transport. Cu 2 MoS 4 contains P and I phases, exhibiting different crystal structures, ion transport characteristics, and electrochemical properties accordingly. In this work, for the first time, Cu 2 MoS 4 electrode materials with dual-phase compositions are designed and prepared for supercapacitor application, providing a synergistic effect with high electron transport efficiency and structural stability. Upon an in-depth optimization process, the optimal CMS-4 sample having P and I phases coexisting yields the optimal electrochemical behavior. The CMS-4@carbon cloth (CC) electrode provides a specific capacity of 33.9 mAh g –1 at 1 A g –1, which is 12.6 and 4.0 times higher than the pure P and I phases, respectively. The assembled MnO 2 @CC//CMS-4@CC supercapacitor exhibits a high energy density of 16.8 Wh kg –1 at 800 W kg –1 power density. The results demonstrate that two-phase coexistence of Cu 2 MoS 4 significantly enhances the electrochemical activities owing to the synergistic effects of P and I phases and provides a promising material for supercapacitor negative electrodes.