Porous and high-strength graphitic carbon/SiC three-dimensional electrode for capacitive deionization and fuel cell applications

Abstract

Three-dimensional electrodes (3DEs) offer great advantages for a variety of electrochemical applications. However, new emerging electrochemical technologies pose a great challenge for 3DEs in terms of their mechanical and chemical properties. Herein, we report the preparation of a 3D graphitic carbon/SiC conductive framework (3D G/SiC) using a chemical vapor deposition (CVD) method. We demonstrate that the deposited graphitic carbon layer can remarkably enhance the mechanical strength of the SiC framework (the compressive strength increased from 1.24 MPa to 2.75 MPa) and provide good conductivity (15.9 S m⁻¹). Furthermore, 3D G/SiC can be used in a flow-through capacitive deionization (CDI) cell under high feed pressure by acting as a structural backbone for 3DEs. An electro-adsorption capacity of 0.5 mg cm⁻² under high loading conditions was achieved using activated carbon granules as the active material. Besides this, 3D G/SiC can act as a robust electrode for current collecting in extremely acidic electrolyte in a direct biomass fuel cell, allowing the construction of a sucrose fuel cell with a maximum volumetric power density of 0.19 mW cm⁻³ that lights up a LED. This work opens up a feasible way to fabricate high-strength carbon based 3DEs for a wide range of applications in energy conversion and environmental treatment technologies.