One-step preparation of NiCo2S4@NiCo-LDH nano-array structures for high-performance supercapacitor electrodes

Abstract

Transition metal sulfides have attracted much attention due to their excellent electrochemical properties. However, their preparation process often requires multiple steps to be completed, which poses difficulties for their application. In this paper, a NiCo₂S₄(NCS)@NiCo-LDH material was successfully prepared as the cathode material for the prepared supercapacitor by a one-step hydrothermal method using a MOF as a sacrificial template. The electrode material exhibits good electrochemical performance due to the regular microstructure with abundant active sites. The electrode material exhibits a specific capacitance as high as 4191.25 mF cm⁻² in the three-electrode system at a current density of 2 mA cm⁻². This is much higher than the sum of the capacitances of the NiCo₂S₄ and NiCo-LDH materials. To further validate its practical application, it was assembled with an activated carbon negative electrode to prepare a high-performance supercapacitor with a scalable voltage window of up to 1.6 V. The device was able to maintain 90% capacity retention after 5000 cycles and showed excellent performance. This work provides a new way to design and fabricate electrode materials with high performance and lifetime.