Advancing sustainable energy through battery repurposing and micro recycling

The global priority to mitigate climate change has intensified the shift toward sustainable energy systems and electric mobility. Lithium-Ion Batteries (LIBs) are central to this transition yet concerns over critical raw material scarcity particularly cobalt and lithium pose significant challenges. Repurposing end-of-life LIBs into Second-Life Batteries presents a viable solution, as many retain 70–80 % of their State of Health (SoH), making them suitable for extended use in stationary energy storage applications. The present review explores key methodologies for assessing LIB health, focusing on SoH and Remaining Useful Life (RUL), which are essential for safe and efficient reassembly. With increasing adoption of electric vehicles, the volume of retired LIBs is expected to flood, intensifying environmental concerns and straining existing waste management systems. The heterogeneous material composition of these batteries further complicates recycling efforts, necessitating the development of advanced, efficient recovery technologies. Emerging approaches, such as hybrid energy storage systems using small-format e-waste LIBs, offer scalable, low-cost solutions for off-grid and community-level energy applications. These systems leverage modular pack design and intelligent Battery Management Systems to integrate cells of varying chemistries and capacities. Simultaneously, micro-recycling and decentralized battery repurposing models are gaining traction, enabling localized battery diagnostics, dismantling, and reuse particularly in resource-constrained regions. The article reviews recent innovations in LIB recycling techniques and evaluates their environmental impacts. It also highlights policy and regulatory frameworks needed to scale these technologies sustainably. Overall, the study underscores the critical importance of circular economy strategies in battery lifecycle management to reduce environmental harm, conserve finite resources, and ensure long-term energy resilience.