Zinc Ions Doping in Layered Bimetallic Nickel-Cobalt Glycerol Nanosheets for Enhanced Electrochemical Performance of Supercapacitors

Supercapacitors, distinguished by their high power density, rapid charge-discharge rates, and prolonged cycle life, hold significant promise in various technological applications. However, limited lower energy density still hinder their practical application. Enhancing intrinsic conductivity by smart choice of elemental combination along with design of nanostructures has the potential to significantly improve the electrochemical performance. Herein, a self-template method was used for the synthesis of Zn-doped hydrolyzed NiCo-glycerate nanosphere (ZnNiCo-G-H) electrode material, assembled with a large number of nanosheets by simple hydrothermal reaction, which can provide abundant active sites and thus achieve superior electrochemical performance. The optimized electrode material displayed a specific capacitance of 1145 F g-1 at 1 A g-1. The fabricated asymmetric supercapacitor, composed of ZnNiCo-G-H and activated carbon as two electrodes, delivered excellent cycling performance with a capacitance retention of 93.8 % after 5000 cycles at the current density of 5 A g-1 and a high energy density of 40 Wh kg-1 at 825 W kg-1, offering great potential as a qualified candidate for the electrochemical energy storage devices. A self-template method was employed for the synthesis of Zn-doped NiCo-glycerate nanospheres assembled with ultrathin nanosheets that provided abundant active sites and large specific surface area. Therefore, it displayed a high specific capacitance of 1145 F g-1 at 1 A g-1. image