MoCl₅-mediated dual-track regulation unlocks high-voltage ether-based quasi-solid-state electrolytes

In situ-polymerized 1,3-dioxolane (DOL) electrolytes offer a promising route to quasi-solid-state lithium metal batteries (QSSLMBs), yet their limited oxidative tolerance and unstable electrode interfaces restrict high-voltage operation. Here, a simulation-guided dual-track regulation strategy uses MoCl₅ as a multifunctional initiator to couple DOL ring-opening polymerization with Li-salt dissociation and inorganic interphase construction. MoCl₅ promotes formation of a high-molecular-weight poly(1,3-dioxolane) (PDOL) matrix and LiF/LiCl/Li_xMo_y-enriched solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI), improving bulk stability, Li⁺ transport, and interfacial robustness. The resulting MoCl₅-regulated PDOL electrolyte achieves a Li⁺ transference number of 0.71 and an electrochemical stability window of 4.7 V. Li||Li symmetric cells cycle for over 1000 hours at 5 mA cm^-2, while high-voltage Li||LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cells retain over 95% capacity after 50 cycles at 2 C. This work establishes a design principle for multifunctional initiators and unlocks the high-voltage potential of ether-based electrolytes, advancing the practical application of QSSLMBs.