MOF derived CeO₂ showed a pseudocapacitance of 1204 F g⁻¹ at 0.2 A g⁻¹, far exceeding its theoretical capacitance (560 F g⁻¹). The present study demonstrates that combination of a two-way strategy, controlled nano-architecture and redox active electrolyte additive, could potentially alleviate both low energy density and capacitance fading issues plaguing the current metal oxide pseudocapacitors.

A spray drying based synthetic protocol is developed for NiCo ₂ O ₄ and rGO–NiCo ₂ O ₄ hollow-spheres using a simple aqueous metal–(NH ₄ ) ₂ CO ₃ solution as the precursor.