Homogeneous low-tortuosity membrane with fast ion transfer towards life-durable low-temperature zinc metal batteries

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.