Urchin-like Ni[sbnd]Co hydroxide@tamarind seed biochar for high performance supercapacitor

Abstract

This study introduces a novel composite material, U-NiCo-OH@TTBC, comprised of tamarind seed biochar (TTBC) and nickel-cobalt hydroxide, designed for high-performance supercapacitors. This composite exhibits a unique urchin-like structure with a specific surface area of 610 m2 g−1, facilitating efficient electron-ion transport and electrolyte diffusion. U-NiCo-OH@TTBC demonstrates an impressive storage capacity of 759 F g−1 at 1 A g−1, along with a specific capacitance of 158 F g−1. The symmetric device built with U-NiCo-OH@TTBC boasts power densities ranging from 787 to 7183 W kg−1 and energy densities between 16 and 54 Wh kg−1. Most notably, the device exhibits exceptional long-term cyclic stability, retaining 92 % of its performance after 10,000 charge-discharge cycles. This work highlights the potential of agricultural waste as sustainable carbon sources and their compatibility with metal hydroxides to create eco-friendly and durable supercapacitor electrodes.