Urea-assisted hydrothermal synthesis of Co3O4/SnO2 composites as a battery-type material for hybrid supercapacitors

초록

Metal oxide composites exhibiting battery-like behavior have attracted increasing attention for application in hybrid supercapacitors (HSCs). The combination of two distinct metal oxides enhances electrochemical activity compared to either oxide alone. In this study, Co3O4/SnO2 composites were synthesized via a hydrothermal method using varying amounts of urea as a structure-directing agent. Four samples, designated CoSn-1, CoSn-2, CoSn-3, and CoSn-4, were prepared with 1, 2, 4, and 8 mmol of urea, respectively. The influence of urea concentration on the structural, morphological, and surface properties of the composites was systematically investigated. Among these, CoSn-3 exhibited a uniform rod-like morphology with small nanoparticles, resulting in an optimal balance of surface area and pore structure. All CoSn electrodes demonstrated battery-type characteristics; however, CoSn-3 achieved the highest specific capacity of 524.00C g-1 at 0.5 A g-1 and retained 93% of its initial capacity after 5000 cycles at 5 A g-1, indicating excellent capacity retention and long-term stability. These findings suggest that tuning the urea content during synthesis can significantly enhance the electrochemical performance of battery-type metal oxide composites in HSCs.

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