Recycled Graphite Anode from Li-Ion Batteries as Host Material in Li–S Batteries

The increasing demand for high-energy storage systems, particularly in electric vehicles and aerospace, has spotlighted lithium–sulfur (Li–S) batteries due to their superior energy density and use of abundant sulfur, offering a sustainable alternative to traditional lithium-ion (Li-ion) batteries. However, critical challenges such as the ‘shuttle effect’ and mechanical instability resulting from volume expansions of sulfur-based electrodes impede their practical application. Recent developments primarily focus on carbon–sulfur composite cathodes, employing materials like graphene, albeit at high energy and cost. Innovative research explores sustainable carbonaceous materials from waste, such as recycled paper and cotton fabric, enhancing electrochemical performance but requiring costly activation and carbonization processes. In addressing these limitations, this study investigates using recycled graphite from spent Li-ion batteries as a sulfur host. We successfully modify graphite’s structure and functional groups by employing acid treatments with H2SO4:HNO3 or methanesulfonic acid (MSA) to enhance polysulfide adsorption, reduce volume expansion, and mitigate the shuttle effect. Our approach bypasses traditional energy-intensive processes, highlighting the potential of upcycled materials for eco–friendly and cost-effective Li–S battery technologies, thus contributing to their sustainable advancement.