关键词: 海水锌空气电池, 氧还原反应, 局域电场, Cl^?固定策略, 单原子催化剂

Abstract: 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.

Key words: Seawater zinc-air batteries, Oxygen reduction reaction, Local electric fields, Cl^? fixation strategy, Single-atom catalysts