Cobalt doping stabilizes the expanded structure of layered double hydroxide cathodes for application in fast charging Ni–Zn batteries

Improving the reversible capacity, fast chargeability, and cyclability of cathode materials are the primary challenges in the development of advanced rechargeable batteries. Herein, we discover the synergetic effects of cobalt ions in achieving a capacity that is approximately equivalent to the theoretical capacity, a highly stable cyclability, and a superior rate capability of Co-doped nickel layered double hydroxides (Ni_1−xCo_x-LDH). The cobalt dopants stabilize the α-phase LDH with an expanded interlayer distance, drawing the redox potential within the voltage stability window and enabling the maximum charging of the cathode. In addition, cobalt doping provides robust nanostructures with a highly porous morphology, which is highly suitable for enhanced rate capability. The optimized Ni_0.9Co_0.1-LDH material exhibits a high specific capacity of 310 mAh g⁻¹ with excellent cycle retention and fast chargeability, indicating a superior rate capability compared to conventional Ni(OH)₂. Consequently, the full cell of the Ni_0.9Co_0.1-LDH cathode and Zn metal anode exhibits maximum energy and power densities of 288 Wh kg^‒1 and 1973 W kg^‒1, respectively. The enhanced performance of Ni_1−xCo_x-LDH indicates its excellent potential as a cathode material with high energy and power densities for safe and sustainable energy storage devices. Graphical abstract: [Figure not available: see fulltext.]