Pragmatically designed tetragonal copper ferrite super-architectures as advanced multifunctional electrodes for solid-state supercapacitors and overall water splitting

Stabilization of tetragonal copper ferrite super-architectures has been proposed for the fabrication of high-performance supercapacitor and water splitting electrodes. The reaction parameters are optimized to keep the tetragonal phase intact (with high yield per batch ~ 7.5 g) in order to have better ions intercalation/de-intercalation processes and longer cycling stability, according to Jahn-Teller distortion theory. The developed porous layered architectures are mesoporous with large specific surface area available for ionic interactions. The redox additive insertion in the electrolyte raises the specific capacity to ~ 450 mAh g⁻¹ (~2490F g⁻¹) from the fabricated electrode. The physical mechanism involved behind the electrochemical performance in presence of redox additives is elaborately discussed to gain insight into the charge storage characteristics. The fabricated asymmetric solid-state supercapacitor exhibits broad potential window (~1.8 V) with excellent energy (128 Wh kg⁻¹) cum power traits, and a long-lasting stable performance for > 10000 cycles. For water splitting, the super-architectures based electrode displays promisingly lower OER/HER (~298/103 mV) overpotentials with excellent stability over longer durations (>30 h). The fabricated symmetric device with the alkaline electrolyte is highly stable with cell voltage of 1.62 V, which being an oxide material is excellent and superior to various oxides/chalcogenides based high-grade materials.