Carbon-embedded mesoporous transition multimetal oxide nanospheres for long-lasting hybrid cells

Recently, multiple transition metal oxide-based materials have been intensely attracted in the field of energy storage owing to their multifunctional properties. Meanwhile, carbon-based materials are considered more reliable electrode candidates due to their high porosity and chemical stability. Herein, we synthesized carbon-embedded transition multimetal oxides as a hybrid composite by a facile hydrothermal method, followed by annealing in inert medium. The effect of different metal ion species (Ni, Co, and Ce) and their combination on the energy storage performance was explored. The carbon-embedded Ni-Co-Ce-Si (C/NiCoCeSi) oxide electrode revealed a higher areal capacity of 35.5 μAh/cm² at a current density of 3 mA/cm² than the C/NiSi oxide and C/NiCoSi oxide electrodes due to the improved redox chemistry. Moreover, the C/NiCoCeSi oxide electrode was subjected to a test involving 10 000 charge-discharge cycles at 7 mA/cm², and it demonstrated the decent capacity retention of 83.8%. Furthermore, the C/NiCoCeSi oxide material was used as a positive electrode in the fabrication of a hybrid cell (HC). The as-fabricated HC demonstrated a good areal capacitance of 105.9 mF/cm² at 1.5 mA/cm² with maximum energy and power densities of 29.2 μWh/cm² and 6350 μW/cm², respectively. Finally, the HC also powered light-emitting diodes to test its practical functionality.