Recyclable multiscale composite structural supercapacitor

Abstract This study presents a proof‐of‐concept for a fully recyclable and sustainable composite structural supercapacitor. The fabricated device shows promising energy storage capabilities and mechanical strength. Generally, structural supercapacitors capacitance is considerably lower than non‐load‐bearing mono‐functional supercapacitors and are made via thermoset polymer electrolyte. Here, the device is fabricated using an optimized solid electrolyte composition of carbon aerogel modified carbon fibers, fumed silica, lithium salt, and a thermoplastic polymer matrix. The supercapacitor exhibits a high capacitance of 5225 mFg⁻¹ (193 mFcm⁻²) at 1 mVs⁻¹ scan rate and a large voltage window of 4 V. A simple dissolution/reprecipitation method is used to demonstrate the recycling feasibility, with minimal mechanical degradation (<10%) in the polymer matrix and no chemical structure changes in the electrolyte. This work establishes a promising ecologically‐sound structural energy storage technology with favorable performance compared to prior studies. Highlights A proof‐of‐concept fully recyclable composite structural supercapacitor is made. Thermoplastic‐based robust polymer electrolytes are fabricated. Recycling via dissolution and re‐precipitation of components is demonstrated. Comparison to prior structural supercapacitors shows favorable performance.