Synthesis of high value-added graphene from spend graphite in lithium-ion battery through electrochemical exfoliation

초록

Since the lithium?ion batteries (LIBs) have been commercialized 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 outstanding characteristics of LIBs such as high energy density and long lifespan, wide operating temperature range, and low self?discharge. However, as the market size continues to increase, the demand for reuse or recycling of spent LIBs, which are causing economic and environmental problems, is also increasing for the environment and sustainable development. 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.[1] However, there is little interest in recycling anode material due to low added value graphite and difficulties in the recycling process. Nevertheless, due to the rapid increase of discarded LIBs and waste graphite, graphite recycling is necessary for the environment and sustainable development. In this study, we investigated a strategy for making high-performance graphene using recycled graphite through the electrochemical approach and reusing it as an anode material for LIBs. The surface and composition of the spent graphite and electrochemically exfoliated graphene were observed through scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, the number and thickness of the synthesized graphene sheet layers were observed through atomic force microscopy (AFM), and residual impurities after graphene synthesis were analyzed through inductively coupled plasma atomic emission spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS). Electrochemical performance of graphene obtained from spent graphite as anode for LIB was evaluated in a half?cell configuration using CR2032 type coin?cells.