Yu Jia, Li Bo-Quan, Zhao Chang-Xin, Liu Jia-Ning, Zhang Qiang
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.
Adv Mater. 2020 Mar;32(12):e1908488. doi: 10.1002/adma.201908488. Epub 2020 Feb 19.
The rechargeable zinc-air battery (ZAB) is a promising energy storage technology owing to its high energy density and safe aqueous electrolyte, but there is a significant performance bottleneck. Generally, cathode reactions only occur at multiphase interfaces, where the electrocatalytic active sites can participate in redox reactions effectively. In the conventional air cathode, the 2D multiphase interface on the surface of the gas diffusion layer (GDL) inevitably results in an insufficient amount of active sites and poor interfacial contact, leading to sluggish reaction kinetics. To address this problem, a 3D multiphase interface strategy is proposed to extend the reactive interface into the interior of the GDL. Based on this concept, an asymmetric air cathode is designed to increase the accessible active sites, accelerate mass transfer, and generate a dynamically stabilized reactive interface. With a NiFe layered-double-hydroxide electrocatalyst, ZABs based on the asymmetric cathode deliver a small charge/discharge voltage gap (0.81 V at 5.0 mA cm ), a high power density, and a stable cyclability (over 2000 cycles). This 3D reactive interface strategy provides a feasible method for enhancing the air cathode kinetics and further enlightens electrode designs for energy devices involving multiphase electrochemical reactions.
可充电锌空气电池（ZAB）因其高能量密度和安全的水性电解质而成为一种很有前景的储能技术，但存在一个显著的性能瓶颈。一般来说，阴极反应仅发生在多相界面，在该界面处电催化活性位点可有效参与氧化还原反应。在传统空气阴极中，气体扩散层（GDL）表面的二维多相界面不可避免地导致活性位点数量不足和界面接触不良，从而导致反应动力学迟缓。为了解决这个问题，提出了一种三维多相界面策略，将反应界面扩展到GDL内部。基于这一概念，设计了一种不对称空气阴极，以增加可及活性位点、加速传质并产生动态稳定的反应界面。采用镍铁层状双氢氧化物电催化剂，基于不对称阴极的锌空气电池具有较小的充放电电压间隙（5.0 mA cm 时为0.81 V）、高功率密度和稳定的循环性能（超过2000次循环）。这种三维反应界面策略为增强空气阴极动力学提供了一种可行的方法，并进一步启发了涉及多相电化学反应的能量装置的电极设计。
