Multifunctional Subnanowires Modulating In Situ Polymerization for High-Voltage Solid-State Batteries

In situ polymerized poly(1,3-dioxolane) (PDOL) electrolytes endow excellent interfacial contact and satisfactory compatibility in lithium metal batteries (LMBs). However, their limited oxidative stability hinders compatibility with high-voltage cathodes. Herein, an effective molecular weight modulation-induced strategy via multifunctional subnanowires (SNWs) was proposed to realize the superior oxidative stability of PDOL electrolytes with narrow molecular weight distribution (MWD). Specifically, the ring-opening polymerization of DOL was promoted by oxygen vacancies (Ov) on SNWs, which enhanced the monomer conversion rate. Simultaneously, the polymerization speed during the in situ process was regulated by the weak adsorption of monomers induced by protonated oleylamine (PO). Furthermore, the dual Lewis acid sites (Ov and PO) of the SNWs facilitate lithium salt dissociation, releasing more movable Li⁺ for transport. Thus, the SNWs-induced polymerized PDOL electrolytes with an MWD of 1.42 exhibit remarkable oxidative stability exceeding 5.1 V while achieving a lithium-ion transference number of 0.81. Consequently, the assembled NCM811||Li cells maintain a stable operation for 100 cycles at 4.5 V with a capacity retention rate of 89.2%. This research first modulates the MWD of in situ polymerized PDOL electrolytes using subnanowires to enhance their oxidative ability, presenting a unique strategy to inspire the development of high-performance LMBs.