School of Environment and Energy, South China University of Technology, Guangzhou510006, China.
College of Automation, Zhongkai University of Agriculture and Engineering, Guangzhou510225, China.
ACS Appl Mater Interfaces. 2023 Jan 25;15(3):3953-3960. doi: 10.1021/acsami.2c18460. Epub 2023 Jan 12.
Alkaline nickel-zinc (Ni-Zn) batteries, as traditional rechargeable aqueous batteries, possess an obvious advantage in terms of energy density, but their development has been hindered by the anode-concerned problems, Zn dendrites, self-corrosion, passivation, deformation, and hydrogen evolution reaction (HER). Herein, to solve these problems, a dual protective strategy is proposed toward the anode using ZnO as an initial active material, including a C coating on ZnO (ZnO@C) and a thin poly(vinyl alcohol) (PVA) layer coating on the electrode (ZnO@C-PVA). In a three-electrode configuration, the reversible capacity can reach 600 mAh g for the ZnO@C-PVA. Using excessive commercial Ni(OH) as the cathode, the alkaline Ni-Zn cells exhibit good electrochemical performance: Discharge capacity can be as high as 640-650 mAh g at 4 A g with a Coulomb efficiency (CE) as high as 97-99% after activity, suggesting low self-corrosion and HER. Capacity retention is 97% after 1200 cycles, indicating rather good durability. The discharge capacity is even slightly increased with the increase of charge/discharge current density (≤8 A g), implying good rate performance. Additionally, the discharge voltage can reach 1.8 V (midpoint value) at various current densities, reflecting the fast reaction kinetics of the anode. Most importantly, no Zn dendrites and passivation are observed after long-term cycling. The strategy proposed here can solve the anode-concerned problems effectively, exhibiting a high application prospect.
堿性镍锌（Ni-Zn）电池作为传统的可充电水系电池，在能量密度方面具有明显优势，但由于阳极相关问题、锌枝晶、自腐蚀、钝化、变形和析氢反应（HER）的存在，其发展受到了阻碍。在此，为了解决这些问题，提出了一种针对阳极的双保护策略，使用氧化锌作为初始活性材料，包括在氧化锌（ZnO）上涂覆碳（ZnO@C）和在电极上涂覆一层薄的聚乙烯醇（PVA）层（ZnO@C-PVA）。在三电极配置中，ZnO@C-PVA 的可逆容量可达 600 mAh g。使用过量的商业 Ni(OH)作为阴极，堿性 Ni-Zn 电池表现出良好的电化学性能：在 4 A g 的电流密度下，放电容量高达 640-650 mAh g，活性后库仑效率（CE）高达 97-99%，表明自腐蚀和 HER 较低。经过 1200 次循环后，容量保持率为 97%，表明具有较好的耐久性。随着充放电电流密度的增加（≤8 A g），放电容量甚至略有增加，表明具有良好的倍率性能。此外，在各种电流密度下，放电电压可达到 1.8 V（中点值），反映出阳极的快速反应动力学。重要的是，长期循环后没有观察到锌枝晶和钝化。这里提出的策略可以有效地解决阳极相关的问题，具有很高的应用前景。
