Ultralong Cycle Life for Deep Potassium Storage Enabled by BiOCl/MXene van der Waals Heterostructures
Xin Cao, Yuying You, Dawei Sha, Huan Xia, Hang Wang, Jing Zhang, Rongxiang Hu, Yicheng Wei, Zhuoheng Bao, Yang Xu, Long Pan, Chengjie Lu, Wei He, Min Zhou, ZhengMing Sun
Abstract
Abstract Conversion/alloying‐type anodes are drawing attention due to their high theoretical capacities, but inferior reversibility, especially under low current densities, has hampered potential applications. Conventional strategies mainly focus on conversion/alloying processes, whereas the intercalation process is rarely analyzed. Herein, the intercalation process is correlated with conversion/alloying processes by ion dispersion states. BiOCl/Ti 3 C 2 T x MXene van der Waals heterostructure is selected as a proof‐of‐concept system. Multifunctional MXenes not only contribute to atomic dispersion and boosted ion diffusion at the first cycle by constructing a novel heterostructure but serve as supporting frameworks to sustain long‐term structural stability. Consequently, a cell with BiOCl/MXene anode delivers an ultralong cycle‐life of running over ten months, maintaining a high capacity of 225 mAh g −1 over 1300 cycles at 100 mA g −1 and a retention of 81.3%. These findings verify that enhanced initial intercalation can facilitate higher reversibility and shed light on developing high‐performance conversion/alloying‐type anodes.