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

ABSTRACT 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 (SiO 2 ─NH 2 ) nanospheres into the electrolyte. The ‐NH groups of the ANFs and the ‐NH 2 groups of the SiO 2 ─NH 2 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||LiFePO 4 cells present excellent cycling stability for 700 cycles at room temperature and 0°C. The solid‐state Li||LiNi 0.6 Co 0.2 Mn 0.2 O 2 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.