Low-Energy Direct Regeneration Methods for Spent Cathode Materials in Lithium-Ion Batteries

The rapid growth of lithium-ion battery (LIB) deployment in electric vehicles and stationary energy storage has intensified concerns regarding resource depletion, waste management, and environmental impact. Conventional recycling methods, including pyrometallurgy and hydrometallurgy, are effective for material recovery but are energy-intensive, chemically demanding, and often result in downgraded products. Direct regeneration of spent cathodes has emerged as a promising low-energy alternative, aiming to restore the structural integrity and electrochemical performance of degraded materials without breaking them down into elemental constituents. This paper reviews recent advances in low-energy direct regeneration strategies, including solid-state sintering, hydrothermal/solvothermal re-lithiation, electrochemical rejuvenation, and gas-phase treatments. Key factors influencing energy consumption, such as pretreatment methods, lithium source selection, reaction conditions, and reactor design, are critically examined. The performance of regenerated cathodes is compared to virgin materials in terms of structural recovery, cycling stability, and rate capability. Furthermore, techno-economic and environmental assessments highlight the potential of direct regeneration to reduce carbon emissions, operational costs, and reliance on critical raw materials. Despite notable progress, challenges remain in handling mixed chemistry, degradation heterogeneity, and scaling up for industrial application. Future perspectives emphasize the integration of green chemistry, smart sorting technologies, and supportive policies to enable a closed-loop and sustainable LIB value chain.

Keywords: direct regeneration, lithium-ion batteries, spent cathode, low energy consumption, circular economy

This presentation is part of the Power-to-X for a Sustainable Future Workshop 2025, taking place on 14–16 September 2025 at the Montien Hotel Surawong, Bangkok, Thailand. The Power-to-X initiative is supported by the Royal Academy of Engineering.