Study of mechanisms and efficiencies of electrochemical lithium recycling system

School of Energy and Chemical Engineering (Battery Science and Engineering)As the lithium-ion battery (LIB) has been widely commercialized for energy storage systems in portable and stationary devices, its production and disposal have dramatically increased over the past few decades. In addition, increasing amounts of electric vehicles (EVs) and energy storage systems (ESSs) causes a dramatic increase in waste LIBs. As lithium is the key material for LIB, this increasing market trend of LIB leads to lithium depletion which is an urgent problem for the future LIB market. To circumvent these issues, various LIB recycling technologies have been researched. However, the conventional lithium recycling methods have a problems of using toxic and high-cost acid chemicals to leach the waste battery materials and consume high energy to increase the temperature by over 100 ???C. This leads to complicate the procedure and requires environmental treatment processes and costs. A new type of lithium recycling system has been proposed to overcome these issues. This electrochemical system is named the waste-to-lithium (WTL) recycling system and can simply extract lithium from the waste lithium materials. By electrochemically charging the WTL system, lithium ions from the waste LIB materials are extracted and pass through the lithium ion conducting solid electrolyte to form lithium ion in the anode compartment of the WTL system. After the charging process, by electrochemically discharging the system, extracted lithium can be transformed into Li2CO3. The concept of the WTL system is proved with pre-treated waste powders from waste LIB. The electrochemical charging and discharging mechanism for WTL were investigated based on the reaction potential difference of OER/ORR, which is dependent on the pH of the solution. And the lithium extraction efficiency showed 82.2 %. For the increasement of the efficiency, the resistance of each component was investigated with impedance spectroscopy. This WTL system needs no additional chemicals and operates at room temperature, which can be a promising system for the low-cost and eco-friendly lithium recycling system for the sustainable future energy market.ope