Fast nanostructured carbon microparticle synthesis by one-step high-flux plasma processing

This study demonstrates a fast one-step synthesis method for nanostructured carbon microparticles on graphite samples using high-flux plasma exposure. These structures are considered as potential candidates for energy applications such as Li-ion batteries and supercapacitors. The samples were exposed to plasmas in the linear plasma generator Pilot-PSI with an average hydrogen ion-flux of ~10 24 m-2 s-1. The parameter window was mapped by varying the ion energy and flux, and surface temperature. The particle growth depended mainly on the sample gross-erosion and the resulting hydrocarbon concentration in the plasma. A minimum concentration was necessary to initiate particle formation. The surface of the sample was covered with microparticles with an average growth rate of 0.2 μm/s, which is significantly faster than most chemical methods. The particles were initially volumetrically grown in in the gas-phase by a multi-phase process and after deposition on the sample their growth proceeded. Scanning and transmission electron microscopy reveal that the core of these microparticles can be made of an * Corresponding author. E-mail: d.aussems@differ.nl (D.U.B. Aussems) 2 agglomeration of nanoparticles, surrounded by crumpled layers of carbon nanowalls. Gas sorption analysis shows sufficient meso-and macropores for fast mass transport. In conclusion, this processing technique could be a novel synthesis route to nanostructure surfaces for electrochemical applications.