Carbon anode thin films for lithium batteries

This paper describes a simple method to create carbon anode films for potential applications to the research field of lithium batteries. Carbon films were prepared using DC magneton sputtering with post-annealing process in the range from room temperature (RT) to 700 °C. Half cells assembled with lithium foils as the counter electrode and 1 M LiPF6 in EC:DMC (1:1 v/v) electrolytic solution was used to evaluate the discharging capacity of prepared anode thin films. We showed that carbon film deposited at RT can be more suitable for an anode material than that of higher temperature annealed films above 400 °C. A variety of analysis methods including X-ray diffraction spectrometry (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were utilized to evaluate the defect density of the films; for example, the more defects on the film were identified when the carbon film was treated at a low temperature such as RT. It is envisioned that DC magnetron-sputtering with optimized process conditions can be useful for fabricating carbon based film anodes. The room temperature (RT) deposited carbon thin film showed a discharge capacity of 223.5 μAh in the first discharge process while the film annealed at 700 °C resulted in a low initial discharge capacity as well as rapid capacity drop. [Display omitted] •DC magnetron sputtered carbon film anodes were fabricated.•Good charge/discharge performance was obtained for films with no heat treatment.•Structural properties of carbon films are explained.