Recent progress in ZnCo2O4 and its composites for energy storage and conversion: a review

Abstract

Transition metal oxides have attracted growing attention for application in energy storage and conversion technologies. In particular, spinel-based materials, such as ZnCo₂O₄, exhibit structures suitable for performing as multifunctional electrodes in energy devices. In fact, great efforts have been dedicated to the design of micro- and nanomaterials based on ZnCo₂O₄, using different synthesis approaches and controlled conditions. Consequently, interesting morphologies and structures have been recently obtained, exhibiting outstanding electrochemical performance. Hence, in this review we report a comprehensive survey of the progress of multifunctional ZnCo₂O₄-based materials, focusing on the development of supercapacitor devices and batteries. The top 10 electrode materials for each application are highlighted, including key findings in the development of slurry-cast or binder-free electrodes. In addition, the main strategies in the design of ZnCo₂O₄-based electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are reviewed, including electrocatalysts capable of performing tetra-electron oxygen reduction reactions (ORRs).