Wearable Fabrics with Self-Branched Bimetallic Layered Double Hydroxide Coaxial Nanostructures for Hybrid Supercapacitors.

We report a flexible battery-type electrode based on binder-free nickel cobalt layered double hydroxide nanosheets adhered to nickel cobalt layered double hydroxide nanoflake arrays on nickel fabric (NC LDH NFAs@NSs/Ni fabric) using facile and eco-friendly synthesis methods. Herein, we utilized discarded polyester fabric as a cost-effective substrate for in situ electroless deposition of Ni, which exhibited good flexibility, light weight, and high conductivity. Subsequently, the vertically aligned NC LDH NFAs were grown on Ni fabric by means of a hot-air oven-based method, and fluffy-like NC LDH NS branches are further decorated on NC LDH NFAs by a simple electrochemical deposition method. The as-prepared core-shell-like nanoarchitectures improve the specific surface area and electrochemical activity, which provides the ideal pathways for electrolyte diffusion and charge transportation. When the electrochemical performance was tested in 1 M KOH aqueous solution, the core-shell-like NC LDH NFAs@NSs/Ni fabric electrode liberated a maximum areal capacity of 536.96 μAh/cm2 at a current density of 2 mA/cm2 and excellent rate capability of 78.3% at 30 mA/cm2 (420.5 μAh/cm2) with a good cycling stability. Moreover, a fabric-based hybrid supercapacitor (SC) was assembled, which achieves a stable operational potential window of 1.6 V, a large areal capacitance of 1147.23 mF/cm2 at 3 mA/cm2, and a high energy density of 0.392 mWh/cm2 at a power density of 2.353 mW/cm2. Utilizing such high energy storage abilities and flexible properties, the fabricated hybrid SC operated the wearable digital watch and electric motor fan for real-time applications.