Current challenges and future opportunities toward recycling of spent lithium-ion batteries

Lithium-ion batteries (LIBs) are widely used as a critical energy storage system for internet of things (IoT), electric vehicles (EV) and various renewable energy sources. However, the widespread use of LIBs has resulted in the significant accumulation of batteries with different chemistries in landfills. Existing methods for LIB recycling are unsustainable, non-environmentally friendly and ineffective at recycling spent LIBs with mixed chemistry. These methods are inadequate to achieve recovery and repurposing of the valuable and sometimes toxic components. This mandates an inherent need to improve the existing processes or develop a novel, sustainable, environmentally friendly and effective alternative process. In this paper, we present a comprehensive review of the current recovery technologies; demonstrating the gaps in understanding, the challenges and opportunities available in the recycling processes. This review will also examine and discuss different fundamental scientific principles and methods that can be employed to develop sustainable and effective recycling processes with an aim to facilitate the LIB recycling industry to shift towards a circular economy.