Hierarchical WS₂@NiCo₂O₄ Core–shell Heterostructure Arrays Supported on Carbon Cloth as High-Performance Electrodes for Symmetric Flexible Supercapacitors

Abstract

Nowadays, rationally preparing heterostructure materials can not only make up for the shortage of individual components, but also exert unexpected performance through synergistic interactions between the components. Herein, a core-shell of WS₂@NiCo₂O₄ screw-like heterostructure arrays grown on carbon cloth (CC) was prepared by a two-step solvothermal method for supercapacitors. As a binder-free flexible electrode, a high areal capacitance of 2449.9 mF cm^-2 can be achieved for WS₂@NiCo₂O₄/CC at a current density of 1 mA cm^-2. Benefiting from the core-shell of the WS₂@NiCo₂O₄ heterostructure, the capacitive property of the flexible WS₂@NiCo₂O₄/CC electrode is better than those of WS₂/CC and NiCo₂O₄/CC electrodes. Based on WS₂@NiCo₂O₄/CC electrodes, the assembled flexible solid-state symmetric supercapacitor (FSS) device shows a high energy density of ∼45.67 W h kg^-1 at a power density of 992.83 W kg^-1. Meantime, the WS₂@NiCo₂O₄/CC-assembled FSS device also exhibits high cycling stability with an excellent capacity retention of ∼85.59% after 5000 cycles.