Homogeneous low-tortuosity membrane with fast ion transfer towards life-durable low-temperature zinc metal batteries
Yongzheng Zhang, Zhou Huiqing, Jianan Gu, Haifeng Yang, Xiaomin Cheng, Jing Zhang, Jitong Wang, Yanli Wang, Hongzhen Lin, Jian Wang, Liang Zhan, Licheng Ling
Abstract
Aqueous zinc metal batteries (AZMBs) have attracted significant attentions in the energy storage field due to their environmental safety. However, sluggish reaction kinetics of Zn(H 2 O) 6 2+ desolvation and corresponding Zn 2+ ion transfer hinder the low-temperature performance of AZMBs. Herein, the boundary inhibition effect of ion-related pathway is initially uncovered, and a homogeneous low-tortuosity separator membrane (LTSM) with enhanced kinetics of ion desolvation and transfer is proposed. This low-tortuosity structure of LTSM significantly enhances the effectiveness of pore sieving effect toward large Zn(H 2 O) 6 2+ clusters, minimizing ion transfer barriers and homogenizing ion flux, as revealed by Raman and sum frequency generation spectroscopies. Encouragingly, the metallic Zn with LTSM exhibits lower nucleation overpotentials of ∼50 mV, showcasing an ultralong lifespan of over 10000 h at 0 °C. Even under −10 °C, a cycle life up to 5000 h is also achieved. The as-prepared full cells assembled with LTSM display the species capacity of 200 mAh g −1 after 4000 cycles at 8 A g −1 under 0 °C. Increasing to 6.3 mg cm −2 , the large areal pouch cell stabilizes for 160 cycles with retained capacity of 315 mAh g −1 , demonstrating feasibility of eliminating the boundary inhibition effect with low-tortuosity separator membrane for practical applications. The boundary inhibition effect has been eliminated by constructing a low-tortuosity separator membrane, enhancing the kinetic-improvement in dissociating Zn(H 2 O) 6 2+ clusters, minimizing ion transfer barriers. Consequently, a durable lifespan up to 10000 h is achieved under low-temperature surroundings and the full cell stabilizes the capacity of 202 mAh g -1 over 4000 cycles.