Microwave plasma enhanced chemical vapor deposited vertical carbon nanoflakes electrodes for electric double layer capacitors

Abstract

Background

As energy storage materials are in an urgent demand and carbon-based nanomaterials provided great potential for battery and supercapacitor. This study applied microwave plasma enhanced chemical vapor deposition (MPE-CVD) to deposit 3-dimensional carbon nanoflakes (CNFs) with distinguished surface area to prepare the electrodes for electric double layer capacitors (EDLCs).

Methods

The vertical growth of CNFs is driven by MPE-CVD using CH₄ as precursor gas. The as-prepared CNFs on titanium plate (CNFs_{_700}/Ti) was optimized by thickness and mass loading as function of the applied power. Raman spectroscopy and field emission scanning electron microscopy analyzed the properties and surface morphology of carbon. The electrochemical properties of the CNFs_{_700}/Ti assembled as Swagelok or pouch cell were evaluated by cyclic voltammetry and galvanostatic charge/discharge for potential developments in supercapacitor.

Significant findings

An unprecedented rapid growth rate of CNFs, 180 μm/h, was dramatically accelerated due to MPE-CVD procedure, and could be applied as electrode for EDLCs. The mechanism of CNFs growth was elucidated based on the temperature measurements in reactor which relates closely to the CNFs growth rate, proved by thickness and mass loading of CNFs. The clarification of CNFs growth mechanism assists future developments of carbon-based materials in energy storage materials.