Preparation of electrochemical supercapacitor based on fluffy sphere-like NiCoCu-carbonate hydroxide

The NiCoCu-carbonate hydroxides were synthesized via a one-step hydrothermal method at different synthesis times and temperatures ((NiCoCu)(OH)₂(CO₃)-X-Y, X-hydrothermal time, 5 ∼ 20 h; Y-hydrothermal temperature, 100 ∼ 175 °C). The resulting materials were comprehensively characterized using XRD, FT-IR, XPS, electron microscopy investigation, and electrochemical measurements. These results demonstrate that (NiCoCu)(OH)₂(CO₃)-X-Y samples exhibit diverse morphologies and possess distinct electrochemical supercapacitor properties. Notably, the comparative analysis reveals that the modified electrode of (NiCoCu)(OH)₂(CO₃)-10 h-100 °C exhibits superior performance compared to Co₂(OH)₂CO₃ and other prepared samples of (NiCoCu)(OH)₂(CO₃)-X-Y. It demonstrates a higher specific capacity of 758C/g at 2 A/g and showcases excellent reversible charge/discharge capability, with an approximate retention rate of 80.8 % after undergoing 5000 cycles. It can be concluded that the electrochemical properties of cobalt-based carbonate hydroxides can be greatly improved by incorporating a variety of active metal cations in Co₂(OH)₂CO₃, as the synergistic effect produced by these different active metals plays a significant role.