Hierarchical flower bud-like P, W co-doped NiCo2S4@MoS2 composites as high-performance electrodes for asymmetric supercapacitor

Abstract

Engineering binary transitional metal sulfides (BTMSs)-based electrode materials with a rationally designed constituent architecture is a viable strategy for improving their rate capability and electrochemical durability, which provides a possibility for their application in supercapacitors (SCs). Herein, a novel three-dimensional (3D) flower bud-like phosphorus and tungsten co-doped NiCo2S4 and MoS2 composites (P, W-NCS@MS) is prepared on conductive carbon cloth using the hydrothermal method. The effects of P, W-doping, or MoS2-combination on the morphology, structure and electrochemical properties of NiCo2S4-based electrode materials are systematically studied. The designed P, W-NCS@MS achieves a high specific capacity of 1250C g−1 at 1 A g−1 and a satisfactory capacity retention of 80 % after 10,000 cycles. In addition, the asymmetric supercapacitor (ASC) constructed through P, W-NCS@MS and activated carbon electrodes delivers a high energy density of 65.0 Wh kg−1 at the power density of 400 W kg−1 and shows satisfactory cycling stability of 85 % capacitance retention after 20,000 cycles. Notably, the assembled ASC device successfully powered electronic devices in a serial circuit, highlighting its prospective applications in energy storage. This work offers a viable design approach for heteroatom doping and hierarchical interface structures in composite electrode materials toward high-performance SCs.