Toward bio-circular, fully organic batteries from non-toxic and bio-derived materials

The development of biodegradable energy storage systems is essential for enabling environmental monitoring devices that can degrade after stable operation. In this work, we present a fully organic, bio-circular battery that uses materials selected using a framework based on their natural occurrence and hazard classification according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). We use redox-active organic molecules, aloe-emodin and luteolin, immobilized on activated coconut charcoal, together with an agarose/carboxymethyl cellulose gel polymer electrolyte and current collectors based on graphite flakes, carbon black, and agarose. The resulting battery delivers 0.7 V and stable electrochemical performance, supplying 8.8 mAh/g after 200 cycles, with 73.6% capacity retention and 98% coulombic efficiency. All components are further integrated into a pouch cell with an agarose packaging and beeswax coating. This prototype exhibits a discharge capacity of 7.1 μAh and 77.9% capacity retention over 20 cycles. Under simulated aerobic composting conditions, the pouch cell shows rapid and substantial disintegration, highlighting its potential for environmentally benign end-of-life scenarios. This work establishes a comprehensive design strategy for bio-circular batteries and demonstrates the applicability of bio-derived, GHS-non-toxic, fully organic materials for sustainable energy storage solutions.