Self-powered recycling of spent lithium iron phosphate batteries via triboelectric nanogenerator

Abstract

The recycling of lithium iron phosphate batteries (LFPs), which represent more than 32% of the worldwide lithium-ion battery (LIB) market share, has raised attention owing to the valuable element resources and environmental concerns. However, state-of-the-art recycling technologies, which are typically based on electrochemical or chemical leaching methods, have critical issues such as tedious procedures, enormous chemical/electricity consumption and secondary pollution. Here, we report an innovative self-powered system composed of an electrochemical LIB recycling reactor and a triboelectric nanogenerator (TENG) for recycling spent LFP. In the electrochemical LIB recycling reactor, the Cl⁻/ClO⁻ pair generated electrochemically in NaCl solution is adopted as the redox mediator to break down LFP into FePO₄ and Li⁺via the redox targeting reaction without extra chemicals. Additionally, a TENG that utilizes discarded components from LIBs including casings, aluminum-plastic films and current collectors is designed to drastically minimize secondary pollutants. Furthermore, the TENG harvests wind energy, delivering an output of 0.21 W for powering the electrochemical recycling system and charging batteries. Therefore, the proposed system for recycling spent LFP exhibits high purity (Li₂CO₃, 99.70% and FePO₄, 99.75%), self-powered features, simplified treatment procedure and a high profit, which can promote the sustainability of LIB technologies.