A catalytically polymerized solid electrolyte enables 450 Wh kg<sup>-1</sup> lithium-metal batteries with thermal-mechanical abuse tolerance.

Tang, Jiawen; Zhang, Junyu; Liu, Jiacheng; Li, Yunsong; Shao, Ahu; Wang, Zhiqiao; Wang, Xin; Jia, Qiurong et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Practical implementation of solid polymer electrolytes is constrained by interfacial instability and manufacturing scalability. Here, we report a roll-to-roll compatible, 9.6-μm-thick solid polymer electrolyte membrane synthesized via in situ 1,3-dioxolane polymerization catalyzed by Lewis-acidic Li<sub>1.3</sub>Al<sub>0.3</sub>Ti<sub>1.7</sub>(PO<sub>4</sub>)<sub>3</sub> on a polyethylene matrix, achieving a 99.1% conversion rate. The resulting membrane demonstrates 191.7 MPa mechanical strength and 418.7 mS ionic conductance at 25 °C. To resolve multiscale interfacial incompatibilities, a dual-additive strategy is employed: tris(4-fluorophenyl) phosphine constructs a fluorine-rich interphase extending positive electrode tolerance to 4.8 V, while Mg(TFSI)<sub>2</sub> forms a Li-Mg alloy lowering the negative electrode Li⁺ diffusion barrier to 0.127 eV. Validated in 1.2 Ah pouch cells, this system attains specific energy and energy density of 456.7 Wh kg⁻<sup>1</sup> and 911.1 Wh L⁻<sup>1</sup> (based on the total mass and volume of the pouch cell, respectively), stable wide-temperature cycling (-20 to 55 °C), and prevents thermal propagation under abuse conditions.