Electrochemical and electronic properties of electrospun NiO–SnO2 nanofibers: Influence of heterojunction composition on energy storage behavior

In this study, heterostructured nanocomposites based on various ratios of NiO and SnO 2 (NS1‒75:25, NS2‒50:50, and NS3‒25:75; %) and pure NiO and SnO 2 were prepared via the electrospinning-calcination method and evaluated for their energy storage performance. Structural and morphological investigations confirmed the formation of nanostructured materials with variable compositions. Porosity analysis revealed that prepared materials exhibited moderate to high specific surface area, between 9.2 and 38.4 m 2 ×g −1 . Morphological images supported these findings, showing interconnected, porous morphologies with various granulations. Mott–Schottky measurements revealed a gradual shift of the flat-band potential, indicating an increased charge carrier density, as a higher amount of NiO was used. Electrochemical performance was evaluated using cyclic voltammetry and galvanostatic charge-discharge techniques. The NS1 sample delivered the highest specific capacitance of 102.86 F × g −1 (cyclic voltammetry, scan rate of 5 mV × s −1 ) and 55.11 F × g −1 (galvanostatic charge-discharge, charging current of 0.1 A), alongside an energy density of 1.91 Wh × kg −1 (charging current of 0.1 A) and a power density of 850.34 W × kg −1 (charging current of 5 A). Then, the stability tests over 500 cycles ( Δ V = 0.5 V, capacitance retention up to 80.2 %) or 2000 cycles ( Δ V = 0.45 V, capacitance retention up to 88.1 %) revealed promising results. • NiO–SnO 2 heterostructures with tunable ratios to optimized energy storage performance. • Mott–Schottky analysis revealed modulation of carrier density with NiO content. • BET surface area strongly correlates with morphology and electrochemical properties. • NS1 (75 % NiO) achieved 55.11 F × g −1 , 1.91 Wh × kg −1 , and 850.34 W × kg −1 . • Enhanced cycling stability through optimized morphology and electronic structure.