Annealing‐Driven Morphological Evolution of MoS2@α‐MoO3 Heterostructures Toward Enhanced Catalysis and Na‐Ion Supercapatteries

This study offers a cost‐effective and high‐yield electrochemical route for synthesizing molybdenum nanocomposites for energy storage and conversion. MoS 2 @α‐MoO 3 heterostructure nanomaterials are synthesized using an affordable electrosynthesis method on graphite substrate, followed by a simple annealing process at different temperatures. Then, graphite/MoS 2 ‐amorphous electrodes are annealed at 30 °C, 40 °C, and 50 °C. Following physicochemical characterizations, statistical and morphological analyses, including monofractal and multifractal formalisms are conducted. Findings indicate increasing annealing temperature enhances surface roughness and irregularity with well‐developed surface morphology. In a redox‐additive electrolyte (1.0 M Na 2 SO 4 + 1.0 M NaI), G/MoS 2 @α‐MoO 3 ‐500||G/rGO Na‐ion asymmetric supercapattery and G/MoS 2 @α‐MoO 3 ‐500||G/MoS 2 @α‐MoO 3 ‐500 Na‐ion symmetric supercapattery are fabricated. The G/MoS 2 @α‐MoO 3 ‐500||G/rGO supplies a specific capacity of 191.79 mAh g −1 , 45.01 Wh kg −1 energy density, and 234.72 W kg −1 power density at 1 A g −1 with 95.4% retention after 10 000 cycles with a broad potential window of 1.30 V. The G/MoS 2 @α‐MoO 3 ‐500||G/MoS 2 @α‐MoO 3 ‐500 demonstrates C S of 207.13 mAh g −1 , E s of 48.62 Wh kg −1 , and P s of 234.72 W kg −1 at 1 A g −1 with 96.4% retention after 10 000 cycles. Tailoring developed morphologies at G/MoS 2 @α‐MoO 3 ‐500 electrode yields catalytically active sites for excellent electrocatalytic activities toward hydrogen evolution reaction ( η j = 10 = 44 mV and Tafel slope of 81 mV dec −1 ) in acidic solution.