MoCl ₅ -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 MoCl 5 as a multifunctional initiator to couple DOL ring-opening polymerization with Li-salt dissociation and inorganic interphase construction. MoCl 5 promotes formation of a high-molecular-weight poly(1,3-dioxolane) (PDOL) matrix and LiF/LiCl/Li x Mo y -enriched solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI), improving bulk stability, Li + transport, and interfacial robustness. The resulting MoCl 5 -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 0.8 Co 0.1 Mn 0.1 O 2 (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.