Aqueous Zinc Batteries with Ultra-Fast Redox Kinetics and High Iodine Utilization Enabled by Iron Single Atom Catalysts

• Published in: Nano-micro letters Vol. 15; no. 1; p. 126
• Main Authors: Yang, Xueya, Fan, Huiqing, Hu, Fulong, Chen, Shengmei, Yan, Kang, Ma, Longtao
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.12.2023; Springer Nature B.V; SpringerOpen
• Subjects: Aqueous batteries; Aqueous electrolytes; Aqueous zinc batteries; Catalysis; Cathodes; Confinement; Electrocatalysts; Electrochemical analysis; Electrode materials; Energy storage; Engineering; Fe single atom catalysts; Iodine; Iodine reduction reaction; Iron; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Reaction kinetics; Rechargeable batteries; Single atom catalysts; Stability; Utilization; Zinc; Aqueous zinc batteries; Fe single atom catalysts; Iodine reduction reaction
• ISSN: 2311-6706; 2150-5551
• DOI: 10.1007/s40820-023-01093-7

Highlights The porous structure and interconnected conductive pathways accommodate a large amount of iodine, entrap polyiodides and guarantee its efficient utilization. While the Fe single atom catalyst efficiently catalyzes the iodine/polyiodide conversion. With “confinement-catalysis” host, the ZnǀǀI 2 battery delivers a high capacity of 188.2 mAh g −1 at 0.3 A g −1 , excellent rate capability with a capacity of 139.6 mAh g −1 at 15 A g −1 and ultra-long cyclic stability over 50,000 cycles with 80.5% initial capacity retained under high iodine loading of 76.72 wt%. Rechargeable aqueous zinc iodine (ZnǀǀI 2 ) batteries have been promising energy storage technologies due to low-cost position and constitutional safety of zinc anode, iodine cathode and aqueous electrolytes. Whereas, on one hand, the low-fraction utilization of electrochemically inert host causes severe shuttle of soluble polyiodides, deficient iodine utilization and sluggish reaction kinetics. On the other hand, the usage of high mass polar electrocatalysts occupies mass and volume of electrode materials and sacrifices device-level energy density. Here, we propose a “confinement-catalysis” host composed of Fe single atom catalyst embedding inside ordered mesoporous carbon host, which can effectively confine and catalytically convert I 2 /I − couple and polyiodide intermediates. Consequently, the cathode enables the high capacity of 188.2 mAh g −1 at 0.3 A g −1 , excellent rate capability with a capacity of 139.6 mAh g −1 delivered at high current density of 15 A g −1 and ultra-long cyclic stability over 50,000 cycles with 80.5% initial capacity retained under high iodine loading of 76.72 wt%. Furthermore, the electrocatalytic host can also accelerate the I + ↔ I 2 conversion. The greatly improved electrochemical performance originates from the modulation of physicochemical confinement and the decrease of energy barrier for reversible I − /I 2 and I 2 /I + couples, and polyiodide intermediates conversions.