Sustainable Recycling of Spent Batteries—Lithium Pre-Extraction from Lithiated Graphite via Chemical Discharging

The lithium-ion battery (LIB)-based electric vehicle (EV) industry is rapidly growing towards a more sustainable and eco-friendly society. However, this increasing demand for LIBs leads to issues such as raw material shortages and environmental concerns related to the mining process. Therefore, battery recycling technologies are emerging as key solutions to address these problems. However, conventional technologies are plagued by complexity, high energy consumption, high CO2 emissions, and low lithium recovery rates. In pretreatment step, the spent batteries are discharged and crushed to produce black powder, which is intermediate stage before metal extraction. In other words, they involve a non-spontaneous change from a thermodynamically stable black powder to a relatively unstable state.

Here, we propose a new battery recycling system that intentionally charges to form lithiated graphite (LiC6) and immerses it into a lithium extraction solution. This solution not only controls the pH but also the reactivity between LiC6 and water. The charged cell is disassembled in the solution, inducing a spontaneous reaction from unstable LiC6 to LiOH. In this reaction, which we term “chemical discharging”, lithium within the layered structure of graphite is released into the solution, forming a LiOH solution. Unlike the conventional processes that typically recover lithium from black powder in the final stage, this method allows for the pre-extraction of lithium from battery. Thus, it is referred to as the lithium pre-extraction process, which consists of four steps: charging, chemical discharging, separation, and recovery. In a scale-up test using 60Ah pouch cell, it demonstrated significant recovery of Li2CO3 with high recovery efficiency and purity exceeding 99.6%. Additionally, this process significantly reduces energy consumption and CO2 emissions compared to conventional methods. In short, lithium pre-extraction through chemical discharging is an innovative battery recycling process that shows high efficiency, eco-friendliness, and rapid recovery rates. Furthermore, because it generates no wastewater or harmful gases are generated, it can be manufactured in mobile form without government regulations. Consequently, it is easier to scale up and commercialize than conventional battery recycling processes. Overall, we believe this technology has great potential for sustainable battery recycling, thereby contributing to the circular economy of the battery market.