Magnetically Enhanced Bioleaching of Spent Lithium-ion Batteries

Abstract

Rechargeable lithium-ion battery (LIB) production has increased gradually over the years, primarily to meet the demand for portable power sources for tiny electronic gadgets, but the recent spike in LIB production is being driven by the EV market's explosive expansion. Governments all over the globe are requiring the production and sale of EVs to lower CO2 emissions and be eco-friendly. However, the environment may get contaminated by the disposal of spent lithium-ion batteries because of their poisonous nature when metals leach out. To avoid pollution in land disposal and recover the metal present, spent lithium-ion batteries are treated to metal extraction using traditional methods. The use of bioleaching for the treatment of spent lithium-ion batteries may provide a more economical and environmentally friendly alternative to conventional technologies in the recovery of metals. Bioleaching was carried out on different types of spent lithium batteries such as Li[NixCoyMn1-x-y]O2 and Li[NixCoyAl1-x-y]O2 at constant pulp density. Spent lithium-ion batteries contain metals like lithium, cobalt, nickel, manganese, and aluminum. To recover lithium, nickel, and cobalt during the bioleaching of spent Li-ion batteries, Acidithiobacillus ferrooxidans (A. ferrooxidans) is used. A weak magnetic field was applied while cultivating the bacteria and bioleaching. The ideal field strength is determined to be 3 mT, which permits the leaching efficiency of Li to reach 100% after only two days of leaching at a pulp density of 3 w/v%, whereas without the external magnetic field, the leaching efficiency is limited to 57% even after four days. After four days of leaching, the leaching efficiency of Ni and Co improved nearly thrice to more than 80%. The suggested magnetic field-assisted bioleaching of wasted LIBs employing A. ferrooxidans is a cost-effective and environmentally friendly technique for recovering precious metals from discarded LIBs.