Reducing cobalt from lithium-ion batteries for the electric vehicle era

Abstract

The steady increase in global sales of electric vehicles (EVs) owes much to high-energy-density lithium-ion batteries, whose energy density and cost are largely dictated by the cathodes. Although Ni-rich, layer-structured cathodes have been adequate for application in the existing fleet of EVs, there are compelling reasons to eliminate Co from the current family of layered oxide cathodes. However, the realization of Co-free cathodes poses significant technical challenges. In this perspective, we compare the performances and cost efficiencies of Co-free Li[Ni_xMn_1−x]O₂ (NM), Co-poor Li[Ni_xCo_yMn_1−x−y]O₂ (NCM), with x > 0.9, and LiFePO₄ (LFP) cathodes, to evaluate their commercial viability for future EVs. We then systematically outline the intrinsic challenges and possible strategies for the development of advanced Co-free/Co-poor layered and LFP cathodes. As battery requirements vary depending on their application, a range of distinct Co-free/Co-poor cathodes will be required to address diverse commercial needs.