Self-Deprotonation of LDHs toward Aqueous Multi-Ion Battery Cathode
Yanlan Ren, Yu Wu, Zhilong Wang, Shimeng Zhang, Jianxiong Gao, Yongqi Lu, Ju Xiao, Hong-Bo Han, Bowen Jin, Jian Guo, Mingfei Shao
Abstract
Layered double hydroxides (LDHs) have emerged as promising cathode materials for rechargeable aqueous multi-ion batteries. However, the cation (de)intercalation process in Co-containing LDHs typically requires a predeprotonation step in alkaline solutions. Even after predeprotonation, the achievable capacity remains limited. In this study, we report for the first time a self-deprotonation phenomenon in a Mn-based LDH in the initial charging process in a neutral solution. Specifically, the terminal hydrogen atoms are removed from the hydroxyl groups in the Mn-based LDH layers, exposing active oxygen sites that facilitate cation intercalation, even without predeprotonation. The Mn-based LDH demonstrates remarkable multi-ion storage capabilities, delivering an average capacity that surpasses Co-based LDH by 280%, Ni-based LDH by 480%, and deprotonated Co-based LDH by 150%. Furthermore, the performance of the Mn-based LDH is comparable to that of predeprotonated Mn-based LDH, highlighting its potential as a high-performance cathode material. Furthermore, nanostructured Mn-based LDH demonstrates high capacity across diverse electrolytes (Li +, Na +, K +, Ca 2+, Mg 2+, and Zn 2+ ) with specific capacities of 289.5, 174.7, 158.6, 417.1, 410.6, and 98.4 mAh g –1, respectively. This work not only demonstrates the feasibility of activating LDHs for cathode applications but also provides valuable insights into the design of high-performance LDH-based materials.