Ion etching modulates the synthesis of CoNiCU sulfide for high-performance supercapacitors

Abstract

The development of electrochemical supercapacitors has attracted a lot of attention in recent years because of the increasing demand for efficient, high-power energy storage. However, SCs' energy storage capacity is still relatively low. Herein, the ternary metal sulfide CoNiCu with an octahedral hollow structure is obtained by introducing Cu²⁺ with great conductivity and etching with hydrothermal vulcanization. The samples exhibit outstanding performance in the supercapacitor due to the synergistic effect of Co, Cu and Ni. Experimental results prove that its specific capacitance is 2047 F g⁻¹ at 1 A g⁻¹. On the other hand, the supercapacitor device demonstrates a remarkable energy density of 87.8 W h kg⁻¹ when subjected to a power density of 632.0 W kg⁻¹, along with outstanding cycling performance (maintaining 92.86% of its capacity after 20 000 cycles at 10 A g⁻¹). Our work offers a simple hydrothermal vulcanization etching method for synthesizing trimetallic sulfides, which shows good prospects for electrochemical energy storage applications.