In-situ thermal polymerization boosts succinonitrile-based composite solid-state electrolyte for high performance Li-metal battery

Solid-state electrolytes with high room temperature ionic conductivity, broad electrochemical window, and favorable thermal stability are crucial for the practical application of all-solid-state lithium-metal batteries. Here, a novel succinonitrile (SN)-based composite solid-state electrolyte (SN-CSSE) is fabricated directly inside the glass-fiber (GF) membrane via in-situ thermal-crosslinking ethoxylate trimethylolpropane triacrylate (ETPTA) monomer, coupled with the liquid SN-based electrolyte. The ionic conductivity, oxidation potential and lithium-ion transference number (T_Li⁺) of SN-CSSE are 0.78 mS/cm, 5.20 V (vs. Li/Li⁺) and 0.68 at ambient temperature, respectively. The coin full cells equipped with high-voltage LiCoO₂ (LCO) and modified Li metal anode deliver excellent interfacial stability, cycling reversibility, and rate capability. Moreover, the LCO/SN-CSSE/Li pouch cell exhibits more superior thermal stability than that of cell with commercial carbonate-based electrolyte during thermal shock test.