Binder–free of NiCo–layered double hydroxides on Ni–coated textile for wearable and flexible supercapacitors

Abstract

Recently, the combination of nickel (Ni) and cobalt (Co) binary hydroxides have been regarded as a promising class of materials due to their excellent redox reversibility and relatively high capacity. In this work, we demonstrate Ni and Co layered double hydroxides (NiCo–LDHs) on Ni–coated textile for wearable supercapacitor (SC) applications. Ni–coated textile was used as flexible current collector and NiCo–LDH nanosheets were deposited on textile as a pseudocapacitive materials. The electrochemical performances of NiCo–LDHs have been evaluated and optimized by varying the mole ratio of Ni and Co via hydrothermal process. The NiCo–LDH electrodes with Ni:Co ratio of 3:7 has the maximum specific capacitance, which is attributed to the CoOOH by improving the conductivity and enlarged interlayer spacing with intercalation of NO3−. Moreover, solid–state NiCo–LDH SC exhibits a maximum volumetric energy density of 1.25 mWh cm−3 at a power density of 47.4 mW cm−3.