A Flexible Single-Ion Gel Electrolyte with a Multiscale Channel for the High-Performance Lithium Metal Batteries

Abstract

Single-ion polymer electrolytes (SIPEs) have attracted attention due to their unique advantage in suppressing lithium dendrite growth. However, the low ionic conductivity seriously restricts the development of SIPEs. Herein, an aerogel-based SIPE with multiscale Li+ conducting channels is proposed for the first time. The microscale Li+ transport channel is constructed through the self-assembly of cyclodextrins and Li+ containing polymer, while the macroscale channel is formed via a unidirectional freeze-drying process. The obtained aerogel exhibits high thermal stability, good wettability, and outstanding mechanical properties (78% stretchability and 50% compression resilience). The aerogel electrolyte exhibits high oxidative stability (∼4.7 V), good ionic conductivity at room temperature (2.5 × 10–4 S cm–1), and high Li+ transference number (∼0.96). The Li||LiFePO4 cells deliver outstanding rate performance and long cycle life (98% capacity retention after 200 cycles at 0.2 C). This work provides new insight toward mechanically flexible and highly performing single-ion polymer electrolytes for Li metal batteries.