Environmental-friendly and effectively regenerate anode material of spent lithium-ion batteries into high-performance P-doped graphite

Opportunity and challenges in recovering and functionalizing anode graphite from spent lithium-ion batteries: A review

Recent concerns have emerged regarding the improper disposal of spent lithium-ion batteries (LIBs), which has garnered widespread societal attention. Graphite materials accounted for 12-21 wt % of LIBs' mass, typically contain heavy metals, binders, and residual electrolytes. Regenerating spent graphite not only alleviated the shortage of plumbago, but also contributed to the supports environmental protection as well as national carbon peak and neutrality ("dual carbon" goals). Despite significant advancements in recycling spent LIBs had been made, a comprehensive overview of the processes for pretreatment, regeneration, and functionalization of spent graphite from retired LIBs, along with the associated technical standards and industry regulations enabling their smooth implementation still needed to be mentioned. Hence, we conducted the following research work. Firstly, the pre-treatment process of spent graphite, including discharging, crushing, and screening was summed up. Next,. Subsequently, graphite recovery methods, such as acid leaching, pyrometallurgy, and combined methods were summarized. Moreover, the modification and doping approach was used to enhance the electrochemical properties of graphite. Afterwards, we reviewed the functionalization of anode graphite from an economically and environmentally friendly view. Meanwhile, the technical standards and industry regulations of spent LIBs in domestic and oversea industries were described. Finally, we provided an overview of the technical challenges and development bottlenecks in graphite recycling, along with future prospects Overall, this study outlined the opportunities and challenges in recovering and functionalizing of anode materials via a efficient and sustainable processes.

Improving Natural Microcrystalline Graphite Performances by a Dual Modification Strategy toward Practical Application of Lithium Ion Batteries

Microcrystalline graphite (MG), as a kind of natural graphite (NG), holds great potential for use as an anode material for lithium-ion batteries (LIBs) due to low raw material cost, good electrolyte compatibility, and relatively long cycle life. Nevertheless, the relatively low reversible capacity and poor initial Coulombic efficiency (ICE) of the MG anode largely limit its practical application in LIBs. In order to improve the lithium storage capacity of MG, three kinds of oxidant intercalators are applied to treat the original MG, and the as-obtained MG is further modified by a thin carbon layer. The results indicate that using H2SO4-C2H2O4 as oxidant intercalators and subsequent carbon coating layer modification are the optimum techniques, and they can increase the interlayer distance, introduce defects to decrease the volume expansion, and generate channels for fast Li+ diffusion. Meanwhile, the carbon coating layer can reduce the specific surface area of graphite and greatly improve the ICE and cycling performance. Especially, the OEMGC-2 anodes prepared by the dual modification strategies represent a high reversible capacity of 349.4 mA h g-1 at 0.2C with a satisfactory ICE of 90.2%, indicating that the MG can also be considered as a high performance and low-cost anode material of LIBs.