Cobalt in lithium-ion batteries

The use of cobalt in lithium-ion batteries (LIBs) traces back to the well-known LiCoO2 (LCO) cathode, which offers high conductivity and stable structural stability throughout charge cycling. Compared to the other transition metals, cobalt is less abundant and more expensive and also presents political and ethical issues because of the way it is mined in Africa (1). Cheaper cathodes have been developed that substitute some of the cobalt with nickel and manganese, and LiNi0.80Co0.15Al0.05O2 (NCA) and LiNi1-x-y CoxMnyO2 (NMC, where x and y <1) are used in the majority of the LIBs in electric vehicles. Nonetheless, in NCA and NMC, cobalt enables high-rate performance and to some extent, enhances cycle stability. We outline research efforts that could further decrease or even eliminate cobalt content in LIBs to lower their cost while maintaining high performance.