Vertically aligned boron-doped diamond nanostructures as highly efficient electrodes for electrochemical supercapacitors

Nanostructured boron-doped diamond (BDD) offers a sizeable ion-accessible area, high mechanical robustness, and high electrical conductivity, and could be a suitable electrode for high-performance electrochemical (EC) supercapacitors. Herein, two morphological BDD films, namely, boron-doped microcrystalline diamond (BMCD) and boron-doped ultra-nanocrystalline diamond (BUNCD), are employed for nanostructuring. The diamond nanopillars are fabricated via the Au mask-assisted reactive ion etching (RIE) method. The nanostructured samples of BMCD and BUNCD are termed BMCD N and BUNCD N . The Raman spectroscopy and X-ray photoelectron spectroscopy measurements of these nanostructured samples confirm the presence of sp 2 in sp 3 -bonded carbon, which combine to offer good EC activity of sp 2 and exceptional stability of sp 3 carbon. These nanostructured BDD samples with enhanced surface area are utilized as electrode materials to construct an electric double-layer capacitor and pseudocapacitor. In 1 M Na 2 SO 4 solution, the maximum specific capacitance of BMCD N is found to be 0.0852 mF cm −2 , whereas, for BUNCD N the value is 0.0784 mF cm −2 . The electrochemical analysis of these samples shows they exhibit superior electron transfer kinetics with 80% capacitance retention after 2000 cycles, which indicates the suitable utilization of these nanostructured samples as electrodes in EC supercapacitors. Nanostructuring boron-doped diamond effectively improves the electrochemical supercapacitor performance with high lifetime stability.