Quasi-Solid-State Dual-Ion Sodium Metal Batteries for Low-Cost Energy Storage

Dual-ion sodium metal||graphite batteries are a viable technology for large-scale stationary energy storage because of their high working voltages (above 4.4 V versus Na/Na⁺) and the low cost of electrode materials. However, traditional liquid electrolytes generally suffer from severe decomposition at such a high voltage, which results in poor cycle life. Herein, we report a stable dual-ion sodium metal battery employing a multifunctional gel polymer electrolyte, which was facilely prepared by in situ polymerizing an ethoxylated pentaerythritol tetraacrylate monomer in an optimized liquid electrolyte with fluoroethylene carbonate as co-solvent and 1,3-propanesultone as additive. This quasi-solid-state electrolyte not only exhibits high oxidative resistance and constructs stable protective layers on the electrode surfaces but also effectively facilitates homogeneous anion and cation fluxes and suppresses the sodium dendrite growth. The as-developed quasi-solid-state dual-ion batteries delivered a high capacity with long cycle life, which could be applied for low-cost energy storage.