Solar-assisted lithium metal recovery from spent lithium iron phosphate batteries

Abstract

Lithium iron phosphate (LiFePO4) batteries have been considered to be an excellent choice for electric vehicles and large-scale energy storage facilities owing to their superiorities of high specific energy, low cost, excellent thermal safety, and long lifespan, leading to numerous scrap batteries. The lithium recovery from spent LiFePO4 batteries could be an alternative to relieve the shortage of resources and prevent the environmental pollution. However, traditional lithium recycling methods are limited in the practical application owing to the enormous consumption of chemical reagents and inevitable secondary pollution. Here we demonstrate a unique solar-assisted flow-through electrolysis method based on a TiO2 photoelectrode with efficient redox shuttles for lithium metal recovery from spent LiFePO4 batteries. The photovoltage generated on the TiO2 photoelectrode compensated the electrolysis potential, resulting in electric energy saving of 20.37% for lithium metal recovery. During the solar-assisted electrolysis process, metallic lithium could be instantaneously deposited on the copper foil avoiding secondary pollution. Moreover, the consumption of the I– solution was minimal via a close-loop flow-through regeneration reaction. 38.37 μg lithium metal was deposited with the energy consumption as low as 12.90 Wh g–1. It is worth noting that the lithium recovery from industrial spent LiFePO4 powders achieved a high recycling efficiency of 97.64%. This work provides a new simple but efficient way to recover lithium metal from spent LiFePO4 batteries.