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 Ni x Co 3- x -B/GO heterostructure material was synthesized through a simple ultrasonic and precipitation method. The prepared Ni x Co 3- x -B/GO heterostructure exhibits significant improvements in supercapacitor performance than Ni x Co 3- x -B. The presence of GO effectively suppresses the excessive growth and accumulation of Ni x Co 3- x -B; therefore, Ni 2.7 Co 0.3 -B/GO exhibits the best performance as an electrode material for supercapacitors: a high specific capacitance ( C m , 1789.72 F g -1 @1 A g -1 ) and excellent rate performance. The asymmetric supercapacitor (ASC) device of Ni 2.7 Co 0.3 -B/GO//AC exhibits a C m 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 Ni 2.7 Co 0.3 -B/GO as both the positive and negative electrodes demonstrates a C m 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.