Bioleaching of Post-consumer LiCoO₂ Batteries Using Aspergillus Niger

Soaring demands for rechargeable Li-ion batteries in portable electronics and electric vehicles drive the unprecedented increase in post-consumer waste generation. Additionally, to fill the gaps between supply and demand for the critical elements in electrode materials, the recycling of waste batteries has become essential. Traditional recycling using high-energy smelting and high-reagent leaching processes generates harmful waste, hence, a new biotechnological process is being searched as a green alternative. Therefore, this study discloses a bioleaching option of LiCoO₂ cathode powder using fungi, Aspergillus niger as the source of metabolic excreted organic acids lixiviant. The results of one-step bioleaching yielded 96% (w/w) lithium, whereas this efficiency was ~ 94% (w/w) with two-step bioleaching of cathode powder fed at a pulp density of 5% (w/v). The efficiency of cobalt in both types of fungal bioleaching was below 1% (w/w). Thus, the study demonstrates the potential of Aspergillus niger in lithium extraction from cathode powder of the battery waste, and the results will further be utilized to improve the design of bioleaching protocols for environmentally friendly recovery of both metals from LiCoO₂ powder.