High-performance supercapacitors using synergistic hierarchical Ni-doped copper compounds/activated carbon composites with MXenes and carbon dots as simultaneous performance enhancers

Abstract

For the fabrication of high-performance supercapacitors, materials with nano-array architecture and the use of multiple-component electrodes are emerging as the main focus of research. In this work, the novel combination of 0D, 1D, and 2D nanomaterials and 3D-nanostructured materials was reported. Specifically, composite materials based on nanoporous activated carbon (AC) and nanowire nickel-doped copper hydroxide compounds (NiDMR) were utilized as the electrode materials, whereas MXenes and carbon dots (CDs) were employed as the diffusion- and surface-process enhancers, respectively. The AC/NiDMR composite electrode yielded an areal capacitance of 71.2 mF cm−2. Upon adding 10 wt% of CDs and MXenes separately, the capacitance was improved by 122.2% and 158.3%, respectively. The highest specific capacitance of 126.9 mF cm−2 was obtained by adding both 5 wt% of CDs and 5 wt% of MXenes, which corresponds to a 178.2% enhancement compared to the pure AC/NiDMR electrode. Extensive analysis shows the synergistically contributing roles of AC, NiDMR, CDs, and MXenes to the enhanced supercapacitor performance. This ground-breaking supercapacitor has the potential to be used in the next-generation energy storage systems based on its improved electrochemical properties, and this novel strategy features opportunities for the unique utilization of nanostructured, multi-component materials in energy storage devices.