Closed‐Loop Recyclable Solid Polymer Electrolytes via Dynamic Lipoate Cross‐Linking

ABSTRACT

Growing demand for electrochemical energy storage has intensified concerns over battery end‐of‐life disposal, driving an urgent need for recyclable electrolyte materials. Here, we report a photo‐curable, chemically recyclable solid polymer electrolyte platform built on a bio‐derived difunctional cross‐linker, poly(ethylene glycol) bis(lipoate) (PEG‐LP ₂ ), prepared from naturally occurring α‐lipoic acid. Visible‐light‐driven copolymerization of PEG‐LP ₂ with poly(ethylene glycol) methyl ether acrylate in the presence of an ionic liquid (BMITFSI, 45 wt%) yields flexible, ionically conductive membranes (1.30 mS cm ⁻¹ at room temperature). The dynamic disulfide cross‐linked network imparts both solid‐like mechanical integrity and chemical recyclability. When assembled into symmetric supercapacitors, the optimized SPE‐65 formulation retains ∼70% of its initial specific capacitance after 6000 galvanostatic cycles at 100 mA g ⁻¹ . Complete catalyst‐assisted depolymerization is achieved using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) under mild, ambient conditions, and subsequent repolymerization regenerates ionically conductive membranes retaining ∼70% of the original conductivity (0.86 mS cm ⁻¹ ). Together, the bio‐derived lipoate cross‐linker, catalytically assisted depolymerization, and regenerated electrochemical performance constitute a sustainable and recyclable SPE manufacture platform for next‐generation supercapacitor applications.