Oxygen-deficient NiMoO4 Nanosheets as Advanced Electrodes for Flexible Solid-state Supercapacitors

Abstract

As a typical battery material, NiMoO4 is a promising candidate for supercapacitors owing to high specific capacity. However, the utilization of redox active sites is severely restricted by the sluggish electrode reaction kinetics. Herein, oxygen vacancies were incorporated into NiMoO4 nanosheets (Ov-NiMoO4) to create more active sites, which occupied the sites of the MoO6 polyhedron. The Ov-NiMoO4 electrodes achieved high specific capacity and rate performance. The symmetrical supercapacitors with Ov-NiMoO4 electrodes achieved maximum area energy density of 12.86 mWh cm−2 and power density of 1112 mW cm−2, keeping 89.89% capacity retention ratio over 20000 cycles.