In-situ fabricated porous Ni-Co-Mo based nanosheet array electrodes for hybrid supercapacitors with long-cycle stability

Abstract

The porous NiCoMo-based ternary nanosheet arrays have been synthesized on carbon cloth (CC) substrate by a simple hydrothermal process combined with electrochemical assisted template etching method. CC@ZnO@NiCoMo composite exhibits charge/discharge activation phenomenon and holds a capacitance of 8.84 F cm−2 after 3000 cycles at 8 mA cm−2. The porous electrode structure formed by etching ZnO template not only makes it easier for the electrolyte to permeate and exposes the active point as much as possible, but also reduces the charge transfer impedance from 1.32 to 0.92 Ω. As expected, Asymmetric supercapacitors assembly with CC@ZnO@NiCoMo composite achieves a high energy density of 0.64 mWh cm−2 at 3.2 mW cm−2 and ultra-high cycle stability of 181 % after 10,000 cycles. The excellent electrochemical properties of the electrode material is mainly attributed to the synergistic effect between the multi-components of the nanosheets and the enrichment of Zn2+ formed by template etching in the solution, which helps to maintain the relatively stable morphology of Ni-Co-Mo based nanosheets.