Cationic and Non-Ionic Surfactant–Assisted Morphological Engineering of CoMoO₄ for High-Performance Asymmetric Supercapacitors

Precise morphology engineering is essential for enhancing the charge-storage capabilities of cobalt molybdate (CoMoO₄). In this study, cobalt molybdate (CoMoO₄, abbreviated as CoMo), cobalt molybdate–cetyltrimethylammonium bromide (CoMo-CTAB), and cobalt molybdate–cetyltrimethylammonium bromide/polyethylene glycol (CoMo-CTAB/PEG) electrodes were synthesized through a cationic–nonionic surfactant-assisted hydrothermal route. he introduction of CTAB promoted the formation of well-defined nanoflake structures, whereas the synergistic CTAB/PEG system produced a highly porous and interconnected nanosheet architecture, enabling enhanced electrolyte diffusion and redox accessibility. As a result, the CoMo-CTAB/PEG electrode delivered a high areal capacitance of 10.321 F cm⁻² at 10 mA cm⁻², markedly outperforming CoMo-CTAB and pristine CoMo electrodes. It also exhibited good rate capability, maintaining 63.64% of its capacitance at 50 mA cm⁻². Long-term cycling tests revealed excellent durability, with over 83% capacitance retention after 12,000 cycles and high coulombic efficiency, indicating highly reversible Faradaic behavior. Moreover, an asymmetric pouch-type supercapacitor device (APSD) assembled using the optimized electrode demonstrated robust cycling stability. These findings underscore surfactant-directed morphology modulation as an effective and scalable strategy for developing high-performance CoMoO₄-based supercapacitor electrodes.