Construction of nano-architected MnCO3 with enhanced pseudocapacitive performance toward ultrafast supercapacitor

MnCO₃ is an exceptional electrode material for supercapacitors, yet it encounters challenges such as inadequate cycle stability and poor conductivity. In this study, MnCO₃ cube arrays have been successfully synthesized onto Ni foam via a hydrothermal method. These ultra-fine cube-shaped MnCO₃ nanoparticles form porous arrays, essential for controlling volume expansion during charging/discharging. An optimized surface boosts active sites, significantly enhancing performance. The MnCO₃ electrode demonstrates remarkable pseudocapacitive characteristics, exhibiting a specific capacitance of up to 370 F g⁻¹. Furthermore, the electrode displays exceptional cycle stability, with no significant capacitance decay observed even after 5000 consecutive charge–discharge cycles, further confirming its reliability for practical applications. Additionally, the assembled symmetric MnCO₃//MnCO₃ supercapacitor device achieves an energy density of 11 Wh kg⁻¹. This study offers a valuable reference for the development of pseudocapacitive materials.