Rational Design of NiCo-borate/GO Heterojunction as a High-Performance Supercapacitor Electrode.

The bottleneck in the preparation of supercapacitors is how to develop high-energy and high-power-density devices by using appropriate materials. Herein, a novel NixCo3-x-B/GO heterostructure material was synthesized through a simple ultrasonic and precipitation method. The prepared NixCo3-x-B/GO heterostructure exhibits significant improvements in supercapacitor performance than NixCo3-x-B. The presence of GO effectively suppresses the excessive growth and accumulation of NixCo3-x-B; therefore, Ni2.7Co0.3-B/GO exhibits the best performance as an electrode material for supercapacitors: a high specific capacitance (Cm, 1789.72 F g-1@1 A g-1) and excellent rate performance. The asymmetric supercapacitor (ASC) device of Ni2.7Co0.3-B/GO//AC exhibits a Cm of 76.6 F g-1@1 A g-1, a large voltage window of 1.6 V, and a high energy density (ED) of 98.0 Wh kg-1. Furthermore, a flexible, all-solid-state supercapacitor assembled with Ni2.7Co0.3-B/GO as both the positive and negative electrodes demonstrates a Cm of 46.9 F g-1@1 A g-1. Even after multiple folding and bending at various angles, the device maintains excellent performance, showcasing remarkable stability. With a power density (PD) of 479.7 W kg-1, the device achieves a high ED of 60.0 Wh kg-1. This work provides valuable insights into the synergistic effects in electrochemical processes based on heterostructure materials.