The Polymer Society of Korea

Abstract

All-solid-state lithium metal batteries (ASSLMBs) offer improved safety and high energy density, but polyethylene oxide (PEO) electrolytes suffer from high crystallinity, resulting in low ionic conductivity and lithium dendrite growth. In this work, lithium silicate (LS) was synthesized from silicic acid and lithium and incorporated into a PEO matrix. The LS additive reduces PEO crystallinity by intercalating between polymer chains and provides additional lithium-ion transport pathways while suppressing unfavorable PEO–Li⁺ interactions. As a result, the optimized LS5 electrolyte (5 wt% LS) exhibits an ionic conductivity of 8.01 × 10⁻⁵ S cm⁻¹ at room temperature. Lithium plating/stripping for 800 h at 0.2 mA cm⁻² at 60ºC without short circuits. Furthermore, LiFePO₄/Li cells with the LS5 electrolyte demonstrate suppressed lithium dendrite growth and stable cycling for 400 cycles at 1C and 1000 cycles at 0.5C. Pouch-cell testing further confirms the practicality of LS5-based ASSLMBs.