Main-group element-boosted oxygen electrocatalysis of Cu-N-C sites for zinc-air battery with cycling over 5000 h
Yifan Li, Aijian Huang, Lingxi Zhou, Bohan Li, Muyun Zheng, Zewen Zhuang, Chang Chen, Chen Chen, Feiyu Kang, Ruitao Lv
Abstract
Developing highly active and durable air cathode catalysts is crucial yet challenging for rechargeable zinc-air batteries. Herein, a size-adjustable, flexible, and self-standing carbon membrane catalyst encapsulating adjacent Cu/Na dual-atom sites is prepared using a solution blow spinning technique combined with a pyrolysis strategy. The intrinsic activity of the Cu-N4 site is boosted by the neighboring Na-containing functional group, which enhances O2 adsorption and optimizes the rate-determining step of O2 activation (*O2 → *OOH) during the oxygen reduction reaction process. Meanwhile, the Cu-N4 sites are encapsulated within carbon nanofibers and anchored by the carbon matrix to form a C2-Cu-N4 configuration, thereby reinforcing the stability of the Cu centers. Moreover, the introduction of Na-containing functional groups on the carbon atoms significantly reduces the positive charge on their outer shell C atoms, rendering the carbon skeletons less susceptible to corrosion by oxygen species and further preventing the dissolution of Cu centers. Under these multi-type regulations, the zinc-air battery with Cu/Na-carbon membrane catalyst as the air cathode demonstrates long-term discharge/charge cycle stability of over 5000 h. This considerable stability improvement represents a critical step towards developing Cu-N4 active sites modified with the neighboring main-group metal-containing functional groups to overcome the durability barriers of zinc-air batteries for future practical applications. Balancing the activity and stability of oxygen electrocatalysts is challenging but crucial for rechargeable zinc-air batteries. Here, the authors report a highly active Cu-N-C catalyst boosted by the main-group element for zinc-air battery with a long cycle stability over 5000 h.