Closed-loop recycling of Li-ion batteries

Abstract

The percentage of electric vehicles (EVs) in the automotive sector is expected to quadruple by 2040, causing concern regarding the material supply required for the production of lithium-ion batteries. Currently, a substantial part of these materials, such as cobalt and lithium, are subject to non-circular economies, have a substantial environmental impact and are mined in countries with unstable political situations.
Up until now, numerous companies have attempted to resolve these issues through the use of pyro- and hydrometallurgical recycling methods. However, they are yet to meet the mandated recycling goals put in place by the European Commission. This enhances the urgency for the development of a novel, efficient and scalable technology for the recovery of valuable material from spent lithium-ion batteries.
In order to achieve such a development, this study proposes to incorporate Bipolar Membrane Electrodialysis into the standard hydrometallurgical recycling approach. During the course of this research, a prototype of this technology was realized and used to investigate its effectiveness. For practical reasons, the research focused exclusively on the metal and acid recovery from leached LCO cathode material.
Within the subsequent experimental phase of this research a critical issue was identified. Namely, the tendency of divalent cobalt ions to precipitate in non-acidic media. The resolution to this issue required the incorporation of Donnan dialysis into the built BPMED setup, which was used to adjust the acidity of the solutions within the different electrolytic compartments.
Ultimately, this approach led to the respectively recovery of 14 and 22 percent of the lithium and cobalt initially present in the feed solution. Simultaneously, the study recovered a significant amount of the starting leaching agent in the form of 0.6 M nitric acid. Whilst additional optimizations are required to improve the recovery efficiencies, the study successfully demonstrates a proof of concept of the proposed solution.