Highly flexible Ni(OH)2/Co(OH)2 composites for low temperature electrochemical capacitors

Abstract

Designing stable and high-efficiency supercapacitor materials is an important element for advancing sustainable energy storage. However, conventional electrode materials usually present insufficient conductivity and poor cycling stability. To solve the above issues, we prepare Ni(OH)2/Co(OH)2 nanosheet structures via one-step hydrothermal route. Due to their unique porous structures, the synthetic sample delivers a specific capacitance of 1520 F g−1 at 1 A g−1. Additionally, the constructed asymmetric supercapacitor shows a capacitive retention of 80% after 10000 times cycling. It also provides 52.5 Wh kg−1 of energy density at a power density of 2701.9 W kg−1. Moreover, the device still maintains its performance even when the temperature drops to 0°C (94% capacitance after 2000 times cycling).