NiMoO4@NiSe2 microspheres as electrode materials for high-performance supercapacitor

• We synthesize NiMoO 4 @ NiSe 2 micro-flower structures by a facile hydrothermal route. • The obtained samples possess a specific capacity of 1193 C g -1 at 1 A g -1 and maintains 84 % of the initial capacitance after 10,000 times cycling. Supercapacitors as novel sustainable energy conversion systems have been a hot spot owing to their high specific capacitance and excellent cycle stabilities. However, the poor electron conductivity limits their further applications. Herein, we synthesize NiMoO 4 @NiSe 2 samples by a controllable hydrothermal route. The heterogeneous structure consists of high conductive nanosheets and high capacitive particles. It can slow down the collapse of electrode materials and enhance the conductivity of material. It also facilitates ion diffusion and faradaic redox reaction, thereby improves the electrochemical performance. The as-synthesized electrode presents a specific capacity of 1193 C g -1 at 1 A g -1 and maintains 82.9 % of the initial capacitance after 10,000 times cycles. A hybrid capacitor is constructed using the composites as the electrode material. It possesses a capacitance of 101 C g -1 at 1 A g -1 and 85.8 % of the retention rate after 10,000 times charging-discharging. This impressive performance of composite could be attributed to their mesoporous surface with high specific surface area (48 m 2 g -1 ). Moreover, the supercapacitor shows excellent flexibility after folding, exhibiting a wide application prospect in the field of supercapacitors. Herein, an assembled asymmetric device delivers a capacitance of 101 C g -1 at 1 A g -1 and 85 % of the retention rate after 10,000 times cycles.