A Guest Cation Screening Principle for Enabling Customized Cathode/Electrolyte Interface Chemistry and Self‐Enhanced Aqueous Zinc‐Ion Batteries
Meiqi Yang, Jianhui Zhu, Jing Lin, Liang He, Minfeng Chen, Yanyi Wang, Jizhang Chen, Shengkui Zhong, Hongwei Mi, Chuanxin He, Dingtao Ma, Peixin Zhang
Abstract
Abstract Intrinsic structural instability and sluggish reaction kinetics at the electrode/electrolyte interface are two critical concerns that block the application of MnO 2 cathode in high‐performance aqueous zinc‐ion batteries. This work proposes a theoretical screening principle to select the compatible guest cation for MnO 2 host, not only to strengthen the structure but also customize high‐efficiency cathode/electrolyte interphase (CEI). As identified, Sr 2+ is selected as the suitable intercalation ion that enable in situ forming the SrSO 4 CEI after partial release upon charge process. Moreover, density functional theory calculation and multiple characterization research indicate that such SrSO 4 interphase shows an electronic insulation to stabilize the interfacial pH, inhibit the Mn dissolution, and promote the efficient de‐solvation of hydrated zinc ions. Benefited from the self‐optimizing cathode/electrolyte interface chemistry, the 2.5% Sr‐MnO 2 one exhibits higher specific capacity (304.1 mAh g −1 at 0.5 A g −1 ), better rate capability (115 mAh g −1 at 10 A g −1 ), as well as higher capacity retention of 87.9% after 1000 cycles at 2 A g −1 , when compared with pure δ‐MnO 2 electrode. This study provides a new insight on understanding the functions of ion intercalation engineering to design robust layered cathode for high‐performance aqueous zinc‐ion batteries and beyond.