B. Jain, A.J. Bandodkar
North Carolina State University,
United States
Keywords: sustainable energy, energy harvesting, biodegradable energy sources, lithium-free
Summary:
Global energy demand is accelerating rapidly, yet current energy storage systems remain environmentally unsustainable due to their reliance on toxic and non-recyclable materials. Over 95% of lithium-ion batteries end up in landfills, releasing harmful electrolytes and heavy metals that contaminate soil and groundwater. To address this critical issue, this work presents a biodegradable, non-toxic zinc-based battery that achieves performance comparable to lithium-ion systems while ensuring complete environmental compatibility. The innovation integrates an in-built ambient energy harvester that continuously scavenges airflow energy, extending the operational life of the device without the need for conventional recharging infrastructure. This study introduces an innovative materials design approach that leverages the high theoretical capacity of zinc (820 mAh g⁻¹) along with newly developed eco-friendly cathode compositions to deliver stable performance across more than 100 charge–discharge cycles. The electrode architecture effectively suppresses dendrite formation and corrosion—two challenges that have historically impeded zinc battery stability—by employing optimised chemical coatings and controlled ion transport pathways. The result is a compact (<0.25 cm²), lightweight (<1 g), and biodegradable power source capable of retaining capacity over prolonged usage with negligible self-discharge. Beyond its electrochemical performance, the battery offers environmental and societal benefits through complete biodegradability and safe end-of-life disposal. It decomposes naturally under mild conditions, eliminating e-waste concerns associated with traditional energy systems. Additionally, its benign chemical makeup enables biocompatible integration with existing bioelectronic and agricultural sensing platforms. The device has been demonstrated for potential use in wearable medical patches, smart textiles, and soil-integrated agricultural sensors, where temporary data collection or stimulation is required followed by natural degradation without recovery or collection. In parallel, an energy-harvesting subsystem under development captures mechanical or thermal gradients from ambient airflow to recharge the battery on-the-fly, achieving partial energy autonomy. This hybrid design allows continuous operation in remote environments and demonstrates significant promise for large-scale sustainability applications, including distributed Internet of Things (IoT) nodes and eco-friendly disposable electronics. The ongoing research roadmap includes detailed electrochemical analyses, environmental life cycle assessments, and prototype demonstrations of the self-recharging function within biodegradable sensor networks. The project’s next phase involves integrating this system into real-life biomedical monitoring and environmental sensing devices. By combining materials sustainability, energy autonomy, and biodegradability, the work establishes a pioneering framework for next-generation energy harvesting and storage.