Flexible hybrid capacitors based on NiMoS@NiCo-LDH composites under variable work conditions†

Abstract

It is well known that the morphology and structure of electrode materials seriously affect the whole performance of devices. Therefore, transition metal sulfides are desirable cathode materials for supercapacitors due to their high conductivity and rich redox active sites. However, the low energy density restricts their large-scale application. Herein, we design NiMoS@NiCo-LDH core–shell structures through facile synthesis routes. The unique structures relieve volume expansion of the electrode materials during charging/discharging and promote the redox reaction. The as-fabricated products deliver a specific capacity of 1456 C g⁻¹ at 1 A g⁻¹. A flexible device based on the obtained cathode provides an energy density of 80.21 W h kg⁻¹ at a power density of 2698.65 W kg⁻¹. It can maintain 85% of its initial capacity after cycling 10 000 times. Furthermore, they still work stably at extreme temperatures ranging from 25 to −20 °C. The asymmetric supercapacitor (ASC) also presents excellent mechanical durability and stability at different bending angles.