Electrolyte refilling as a way to recover capacity of aged lithium-ion batteries

Lithium-ion batteries are widely used in portable devices and electric vehicles, and their production grows continuously. Aging is the main reason for battery retirement, which causes substantial waste production and can potentially result in water or soil pollution. Capacity recovery of aged cells could become a great alternative to their recycling. In this work, we found that electrolyte refilling restores the capacity of Li-ion pouch cells due to a decrease in internal impedance. The capacity increment depends on the battery State-of-Health (SoH) prior to refilling (20–100%) and is insignificantly affected by the electrolyte extraction method employed (supercritical and normal-pressure electrolyte extraction). The electrolyte extraction does not influence either composition or electrochemical characteristics of the active materials. The obtained results pave the way for enhanced second life applications of lithium-ion batteries.