Browsing by Author "Alhashim, Salma Hashim"

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    Green Recycling of Lithium-ion Batteries
    (2024-04-19) Alhashim, Salma Hashim; Ajayan, Pulickel M.
    Lithium-ion batteries (LiBs) manifest themselves as an important building block in the move towards a net-zero carbon emission economy, and they have been crucial in defining national and international energy policies. Globally, the use of LiBs is projected to increase by almost three folds from 250 million units in 1998 to 700 million units in 2030. This has created two challenges, namely LiB waste management and supply of critical materials (e.g., cobalt, nickel, lithium, and manganese). This PhD work explores viable approaches for green recycling of LiBs. Deep Eutectic Solvents (DESs) are green lixiviants that show immense potential in the efficient hydrometallurgical recycling of LiBs owing to their polarity and non-toxic nature. However, there have been very few attempts to understand and investigate the leaching mechanisms of transition metals and Li from LiB cathode materials using DESs, which is essential in formulating large-scale procedures for industrial-scale battery recycling. In my work, I have tried to understand how the various reaction parameters including temperature, time, solid-to liquid ratio and DES composition affects the leaching efficiencies from common cathode materials (such as NCA, NMC811, and NMC111) using an ethylene glycol (EG): choline chloride (ChCl) based DES. The use of spectroscopy coupled with theoretical calculations revealed a hydrogen-bond mediated leaching mechanism that is heavily reliant on the DES composition. Furthermore, there is a quest for innovative metal recovery strategies to address concerns over expediting the leaching step and reducing energy consumption. This work showcases microwave-assisted cathode leaching leading to a rapid Li extraction (>50% in 30 sec) for varying cathode compositions. Nearly 100% Li leaching efficiency is obtained in just 30 minutes, holding a great potential for facilitating time-efficient selective Li recovery.