Electrochemical exfoliation in used anode of lithium-ion battery for conversion from spent graphite to high value-added graphene

초록

After the commercialization of lithium-ion batteries (LIBs) by SONY in 1991, the global market size of LIBs is expected to grow from USD 41.1 billion in 2021 to USD 116.6 billion by 2030 due to the outstanding characteristics of LIBs such as high energy density, long lifespan, wide operating temperature range, and low self?discharge. At the same time, the global size of the battery recycling market is expected to reach $18.1 billion by 2030, and is expected to grow gradually to address environmental and sustainable challenges. Up to now, recycling electrode materials have mainly focused on cathode materials due to the presence of expensive transition metal elements as well as lithium. However, there is little interest in recycling anode material due to low added value graphite. Nevertheless, considering the rapid increase of discarded LIBs and waste graphite, graphite recycling is necessary for the environment and sustainable development. In this study, we investigate a strategy to make electrochemically exfoliated graphene (EEG) using spent graphite, and reuse it as anode material for LIBs. The morphological structure and composition of the spent graphite and EEG are observed through scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, the number and thickness of the EEG sheet layers were observed through atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Electrochemical performance of EEG as anode for LIBs was evaluated in a half?cell configuration using CR2032 type coin?cells.