On the role of UV crosslinking to enhance moderate-temperature operation of truly solid-state Li-metal batteries based on recycled-PVB-modified polyether electrolytes

Unleashing the potential of truly solid-state lithium metal batteries (SSLMBs) requires scalable, industrially viable manufacturing compatible with mild processing conditions. At the same time, promoting sustainable practices, such as material reuse and waste reduction, is essential for environmentally responsible, sustainable-by-design battery development. Herein, we report a flexible, self-standing, truly solid polymer electrolyte (SPE) fabricated via simple, solvent-free UV-induced crosslinking (UV-curing) process that supports moderate-temperature, large-scale manufacturing. The crosslinked polymer electrolyte combines poly(ethylene oxide) (PEO), the ion-conductive phase, with recycled poly(vinyl butyral) (Re-PVB), a mechanically robust polymer derived from laminated glass waste. Electrochemical studies reveal that the UV-cured SPE has excellent compatibility with lithium metal, enabling stable lithium plating/stripping with low interfacial resistance at 40 °C. Moreover, laboratory-scale truly SSLMB cells with high-loading LFP catholyte (12 mg cm−2) show remarkable performance with almost full specific capacity delivered at low C-rate and excellent rate capability. Noteworthy, promising performance is also obtained in Li-metal cells with high-loading NMC811 catholyte (7 mg cm−2). Overall, this dual-modified SPE development strategy, combining UV-crosslinking and the use of recycled polymers, offers an energy-efficient and sustainable route toward high-performance solid polymer electrolytes, advancing the practical and eco-friendly development of next-generation SSLMBs.