Construction of Low-Crystallinity Three-Dimensional Flower-like Cobalt-Doped Nickel Hydroxide for High-Performance Nickel–Zinc Batteries
Lihong Zheng, Fenyun Yi, Jiahui Liang, Min Lü, Jie Kong, Aimei Gao, Dong Shu
Abstract
The main limitations of aqueous nickel–zinc batteries are their relatively low energy density and short cycle life, which are inextricably linked to the limitations of nickel-based cathodes. In this study, a low-crystallinity flower-like cobalt-doped nickel hydroxide (α-Ni(OH) 2 -0.2Co) is constructed by hydrothermal reaction and employed as high-energy-density cathode for aqueous rechargeable nickel–zinc batteries. Cobalt doping initiates the formation of a flower-like structure and lowers the material’s crystallinity, conferring it with a larger specific surface area, more redox reaction sites, and shorter ion diffusion paths. The optimized α-Ni(OH) 2 -0.2Co electrode manifests a considerable specific capacity of 772 C·g –1 at 1 A·g –1 and remarkable rate performance, with a capacity retention of 75% at 10 A·g –1 . The α-Ni(OH) 2 -0.2Co//Zn battery constructed with α-Ni(OH) 2 -0.2Co as the cathode exhibits a considerable specific capacity of 198 mAh·g –1 at 1 A·g –1 in an alkaline electrolyte. Additionally, the battery exhibits a substantial energy density of 326.7 Wh·kg –1 and a power density of 16.5 kW·kg –1, exceeding the performance metrics of most previously documented aqueous nickel–zinc batteries. This research presents a viable approach for developing advanced cathode materials for nickel–zinc batteries.