Zn ion diffusion in spinel-type cathode materials for rechargeable batteries: the role of point defects

Oxides with spinel structure are attracting increasing attention as potential cathode materials for multivalent ion batteries, such as those based on Mg2+, Ca2+ and Zn2+. Their electrochemical performances generally depend on synthesis conditions, as the intercalation properties of such materials can be highly influenced by the amount and distribution of point defects. In this work we employ atomistic modelling techniques to investigate the trends in the energetics of point defects formation and Zn2+ diffusion in spinel-type ZnCo2O4, in order to shed light on the correlation between structure, defects and intercalation properties. The results of this study indicate that ZnCo2O4 has the potential to be used as cathode material in Zn-ion rechargeable batteries and that synthesis approaches aimed at reducing the degree of spinel inversion and introducing cation under-stoichiometry are expected to improve the intercalation properties of this class of compounds.