Oxygen vacancy-engineered ultrathin NiCo 2 O 4 nanosheet arrays derived from MOFs as an advanced electrode for supercapacitors.

To overcome the poor electronic conductivity and slow ion transport of NiCo 2 O 4 , ultrathin nanosheet arrays with oxygen vacancies are constructed by a facile NaBH 4 reduction method using a bimetallic MOF as the precursor. Benefiting from the advantages of highly exposed surface area and short paths for charge transport of ultrathin 2D nanosheets, as well as the improved electronic conductivity arising from oxygen vacancies, the optimal 0.1-O v -NiCo 2 O 4 /NF electrode shows excellent electrochemical performance, largely outperforming pristine NiCo 2 O 4 /NF.