Hydrogen-Bond Reinforced Composite Electrolytes for Room-/Subzero-Temperature, Highly Stable Lithium Metal Batteries

Succinonitrile (SN)-based electrolytes with high ionic conductivity are considered as a promising candidate for all-solid-state lithium metal batteries (LMBs). However, the decomposition of SN on the lithium metal electrode surfaces severely challenges the stable operation of LMBs. Herein, this work introduces a hydrogen-bond strategy to enhance the cycling stability of SN electrolyte-based LMBs by incorporating accessible aramid nanofibers (ANFs) and amino-functionalized silica (SiO₂─NH₂) nanospheres into the electrolyte. The -NH groups of the ANFs and the -NH₂ groups of the SiO₂─NH₂ establish multiple hydrogen-bonds with the -C≡N groups of SN in the electrolyte, suppressing SN decomposition and blocking the deleterious SN-lithium metal interaction. Additionally, the composite electrolyte facilitates uniform Li⁺ deposition on the lithium electrodes and inhibits dendrite growth. Consequently, the composite electrolyte-based Li||Li symmetrical cells display an exceptional cyclic durability, surpassing 2600 h. Furthermore, the electrolyte-based Li||LiFePO₄ cells present excellent cycling stability for 700 cycles at room temperature and 0°C. The solid-state Li||LiNi_0.6Co_0.2Mn_0.2O₂ cells with a high active mass loading of 10 mg cm^-2 also deliver superior cycle performance. This work adopts the multiple hydrogen-bond interaction for highly stable SN-based solid-state LMBs.