开发适用于海水电解质的高性能氧还原反应（ORR）电催化剂是实现海水锌空气电池（SZABs）发展的关键。本文提出了一种在双金属单原子催化剂（DSACs）中构建局域电场耦合Cl⁻固定策略，所制备催化剂在海水电解质中表现出优异的ORR性能，其半波电位（E_1/2）高达0.868 V，组装的SZABs最大功率密度（Pmax）达182 mW cm⁻²，显著优于Pt/C催化剂（E_1/2: 0.846 V; Pmax: 150 mW cm⁻²）。原位表征和理论计算表明，Fe位点比Co位点具有更强的Cl⁻吸附亲和力，能够在ORR过程中优先吸附海水中的Cl⁻，并通过同离子排斥效应构筑低Cl⁻浓度的局域微环境，从而抑制Cl⁻对Co活性中心的吸附和腐蚀，实现优异的催化稳定性。此外，Fe-Co原子对之间的定向电荷迁移形成局域电场，优化了Co位点对含氧中间体的吸附能，进一步提升ORR催化活性。

The development of robust electrocatalyst for oxygen reduction reaction (ORR) in seawater electrolyte is the key to realize the seawater electrolyte-based zinc-air batteries (SZABs). Herein, constructing a local electric field coupled with Cl^— fixation strategy in dual single-atom catalysts (DSACs) is proposed, and the resultant catalyst delivers considerable ORR performance in seawater electrolyte, with a high half-wave potential (E_1/2) of 0.868 V and a good maximum power density (Pmax) of 182 mW cm⁻² in the assembled SZABs, much higher than those of the Pt/C catalyst (E_1/2: 0.846 V; Pmax: 150 mW cm⁻²). The in-situ characterization and theoretical calculations reveal that the Fe sites have a higher Cl⁻ adsorption affinity than the Co sites, preferentially adsorbs Cl⁻ in seawater electrolyte during the ORR process, thus constructs a low-concentration Cl⁻ local microenvironment through the common-ion exclusion effect, which prevents Cl⁻ adsorption and corrosion the Co active centers, achieving impressive catalytic stability. In addition, the directional charge movement between Fe and Co atomic pairs constructs a local electric field, optimizing the adsorption energy of Co sites for oxygen-containing intermediates, and further improving the ORR activity.