Controllable synthesis of NiCo layered double hydroxide sheets on laser-induced graphene as electrodes for high-performance supercapacitors

Abstract

The development of high-efficiency electrode materials is very important for energy-storage devices with excellent performance. Graphene-based composites are known to be one of the most attractive electrode materials. Herein, NiCo-LDH@PX-LIG was prepared successfully, which could be used to build supercapacitor devices. In this study, LIG sheets were synthesized via a simple laser-direct-writing technology. Through controlling the laser power, a series of LIG sheets were obtained, which were demonstrated to be excellent candidates for depositing NiCo-LDH sheets under hydrothermal conditions. The results showed that the obtained NiCo-LDH@P12-LIG electrode exhibited outstanding electrochemical performance, including areal specific capacitances of 2072 and 1820 mF cm⁻² at 2.5 and 25 mA cm⁻², respectively, and a retention of 91% after 6000 cycles. An asymmetric supercapacitor device was fabricated using NiCo-LDH@P12-LIG as the positive electrode, and showed a high areal energy density of 0.26 mWh cm⁻² at an areal power density of 2.05 mW cm⁻², and excellent cycling stability (retention of 107% after 6000 cycles). This study provides a synthesis method for a graphene-based hybrid electrode material with excellent electrochemical performance, which is simple and efficient, and provides a new idea for the development of sustainable energy storage.