Authors: Siqi Zeng, Shuang Chen, Zhuoran Ao, Xiaolong Lin, Lijing Yan, Chenyu Liu, Zhan Lin
Published: 2025-04-05
Source: Full article
AbstractAqueous Zn‐I2 battery is an overwhelming candidate for sustainable energy storage systems due to its high safety, low cost, and environmental friendliness. However, the serious self‐discharge and the shuttle effect initiated by soluble polyiodides significantly hinder further development. Herein, a pitch‐derived carbon (PPCMK) with a unique micro‐/mesopores structure and abundant oxygen‐containing functional groups is prepared, with dual‐mechanism anchoring of iodine species to effectively confine the polyiodides for alleviating the above problems. The rich micropores of PPCMK (0.62 nm) function to inhibit the formation of I3−, and the large specific surface area enables a high I2 uptake of 64.51%. Moreover, oxygen‐containing functional groups of PPCMK further enhance the interaction with I3− to strengthen the polyiodide confinement. Therefore, the Zn‐I2 batteries exhibit a high specific capacity of 236.76 mAh g−1 (4 mgiodine cm−2) with an average Coulombic efficiency of 99.73% at 1 C, low self‐discharge rate of 18.18% capacity loss after one‐week resting, and superior durability of 20 000 cycles at 20 C with 95.08% retentive capacity. Especially, the pouch cell exhibits a superior area capacitance of 5.51 mAh cm−2 at a high‐loading (30 mgiodine cm−2). This study provides an economically effective solution for the large‐scale production of high‐performance Zn‐I2 batteries.