As a crucial part of electric energy storage devices, nickel-zinc alkaline aqueous batteries have received increasing research interests. However, the low energy/power densities and limited stability seriously impede their large-scale application in electrochemical energy storage. Herein, a simple hydrothermal method is used to synthesize uniform single-crystal β-Ni(OH)₂ quasi-nanocubes (β-NQNCs). And the β-NQNC cathode is used for developing stable aqueous Ni-Zn battery with good energy density. The nanosized β-NQNCs with single-crystal structure can enhance the stability of the cathode and speed up the charge transfer process. The exposed polar (001) crystal facets possess high surface energy and high reactivity. The adsorption of SO2-4 ions may be one possibility for the preparation of β-NQNCs. And the prepared β-NQNC//Zn battery shows ideal areal specific capacity (0.34 mA h cm^-2 at 0.36 mA cm^-2), areal energy density (0.592 mW h cm^-2) and power density (5.612 mW cm^-2). More importantly, the battery exhibits good flexibility under bending. This work may provide new insights into designing aqueous rechargeable batteries with good energy density of nano-single-crystal electrodes.

镍锌碱性水电池作为电能存储设备的重要组成部分，已引起越来越多的研究兴趣。然而，低的能量/功率密度和有限的稳定性严重阻碍了它们在电化学能量存储中的大规模应用。在此，使用简单的水热法合成均匀的单晶β - Ni（OH）₂准纳米晶（β - NQNCs）。和β -NQNC阴极用于开发含水镍锌电池具有良好的能量密度是稳定的。纳米β-具有单晶结构的NQNC可以增强阴极的稳定性并加快电荷转移过程。暴露的极性（001）晶面具有较高的表面能和较高的反应性。SO2-4离子的吸附可能是制备β- NQNCs的一种可能性。制备的β- NQNC // Zn电池具有理想的面比容量（0.34 mA h cm ^-2在0.36 mA cm ^-2），面能量密度（0.592 mW h cm ^-2）和功率密度（5.612 mW cm ^-2））。更重要的是，电池在弯曲下表现出良好的柔韧性。这项工作可能为设计具有良好能量密度的纳米单晶电极的水性充电电池提供新的见识。