Synthesis of Ni, Co, and Mn multi-metal oxide honeycomb materials for all-solid-state asymmetric supercapacitors

A 3D honeycomb-like Ni–Co–Mn oxide composite is grown on carbon cloth. • Multi-component synergy enhances charge storage. • The electrode delivers 349.7 mAh g −1 and retains 90% capacitance after 30,000 cycles. • An asymmetric device achieves 68.99 Wh kg −1 and 98.33% retention after 20,000 cycles. Exploring promising electrode materials with enhanced specific capacitance, cyclic stability, and capacitance retention for supercapacitor (SC) applications remains a significant challenge. Herein, a three-dimensional (3D) honeycomb-like porous ternary Ni-Co-Mn metal oxide composite electrode material was successfully grown on a carbon cloth (CC) substrate, serving as a promising multifunctional candidate for high-performance supercapacitors. In this design, NiCo and NiMn precursors were first fabricated on the surface of carbon cloth via a facile two-step hydrothermal deposition route, followed by in situ high-temperature annealing to yield a high-performance electrode material. Multiple characterization techniques indicate that the electrode material exhibits a 3D porous structure comprising NiCo 2 O 4 , Ni 6 MnO 8 , NiMnO 3 , and CoMnO 4 , collectively denoted as NC@NM-O. Leveraging the synergistic effects of multiple components and unique structural features, the NC@NM-O electrode delivers an ultra-high specific capacitance of 2517.54 F g −1 at a current density of 1 A g −1 and maintains 90.02% capacitance retention at a high discharge rate of 10 A g −1 after 30,000 cycles. An asymmetric all-solid-state supercapacitor, assembled with an activated carbon (AC) negative electrode (NC@NM-O//AC), achieves an energy density of 68.99 Wh kg −1 and a power density of 827.99 W kg −1 at a working voltage of 1.8 V. After 20,000 cycles, the device maintains an impressive capacitance retention rate of 98.33%. Overall, this work demonstrates that rationally designed, multi-component transition metal oxides can serve as advanced battery-type electrode materials for energy storage devices and provides a promising strategy for the development of next-generation high-performance supercapacitors. Download: Download high-res image (152KB) Download: Download full-size image