Ultrafast high-capacity NiZn battery with NiAlCo-layered double hydroxide

High-performance, low-cost, safe and environmentally friendly batteries are important for portable electronics and electric vehicles. Here, we synthesized NiAlCo-layered double hydroxide (LDH) nanoplates attached to few-walled carbon nanotubes (NiAlCo LDH/CNT) as the cathode material of a rechargeable NiZn battery in aqueous alkaline electrolytes. The α-phase nickel hydroxide with ultrathin morphology and strong coupling to nanotubes afforded a cathode with a high capacity of ∼354 mA h g−1 and ∼278 mA h g−1 at current densities of 6.7 A g−1 and 66.7 A g−1, respectively. Al and Co co-doping is unique for stabilizing α-phase nickel hydroxide with only a small capacity loss of ∼6% over 2000 charge and discharge cycles at 66.7 A g−1. Rechargeable ultrafast NiZn batteries with NiAlCo LDH/CNT cathode and a zinc anode can deliver a cell voltage of ∼1.75 V, energy density of ∼274 W h kg−1 and power density of ∼16 kW kg−1 (based on active materials) with a charging time of <1 minute. The results open the possibility of ultrafast and safe batteries with high energy density.