Electrochemical Synergistic Recycling: Coupling Lithium Extraction with Regeneration of Spent LiFePO4 Cathode Materials

With the widespread application of lithium-ion batteries, a large amount of spent lithium-ion batteries will be produced every year, and their recycling and reuse pose an imminent issue. The conventional recycling methods, such as pyrometallurgy and hydrometallurgy, usually involve various processes like calcining, leaching, enriching, purifying, precipitating, and filtering. They are associated with high energy consumption, large amounts of acid and alkali reagent utilization, and therefore high recycling costs. Currently, recycling waste electrode materials containing high value metals, such as Li, Co, Ni and Mn, has been commercially successful. However, it faces an economical dilemma for recycling spent LiFePO4 cathode material which comprises cheap Fe and P elements except for high value lithium element, especially when the lithium price goes down. Here, this work demonstrates an electrochemical recycling strategy that directly combines lithium extraction from waste cathode materials with the regeneration of spent lithium iron phosphate cathode materials. Experimental results demonstrate the feasibility of effective lithium extraction of waste cathode materials, and adequate lithium replenishment of spent LiFePO4 electrodes driven by positive bias of 0.3 V (vs SHE). The leaching rate of the waste electrode materials reaches 95%, and the regenerated LiFePO4 electrode exhibits a high specific discharge capacity of 125.40 mAh g–1 at 5 C. This synergistic recycling method avoids the various processes in traditional recycling methods and their related high energy consumption, large amount of wastewater disposal, and carbon dioxide emission, thus exhibiting high economic benefit and environmentally benign significance.