High-energy argon implantation in carbon nanowalls as a way to produce electrodes for supercapacitor applications

Abstract

While ion implantation is a well-established technology in microelectronics, its potential for modifying carbon-based electrochemical energy storage materials remains underexplored. This study breaks new ground by demonstrating high-energy (40 keV) argon ion implantation as an effective strategy for tailoring the structure and properties of carbon nanowalls, a significantly contrasting with conventional low-energy approaches. Our findings reveal distinctive implantation-induced effects: crystal lattice reorganization, nanoholes formation, and unexpected surface functionalization after air exposure despite using chemically inert argon ions. These phenomena, validated through molecular dynamic simulations, represent previously unreported effects of high-energy ion treatment on carbon nanostructures. We highlight an important dependence of both structural evolution and electrochemical performance on implantation dose. TEM analysis shows that the dose of 1 × 1014 cm−2 does not lead to structure modification evidenced by Raman spectroscopy, while the fluence of 5 × 1015 cm−2 makes the structure thicker with the high amorphization degree. However, at an optimal dose of 1×1014 cm−2, the modified CNWs exhibit a fivefold capacitance enhancement (0.5 mF cm−2 versus 0.1 mF cm−2 for pristine CNWs), representing a unique compromise between beneficial defect generation and excessive structural damage. This study demonstrates the importance of optimizing ion implantation parameters to enhance material properties for supercapacitor applications.