Electrodes Based on Carbon Nanomaterials: Structure, Properties, and Application to Capacitive Deionization in Static Cells

Abstract

Both fibrous- and corpuscular-like materials based on activated carbon, which are considered as electrodes for capacitive deionization, were investigated with a method of standard contact porosimetry. Nanosized pores as well as micro- and macropores have been recognized for the investigated materials. It was found that the hydrophilic specific surface area that is provided by the smallest mesopores and micropores has been found to reach 520–850 m2 g−1; total surface area is 940–1520 m2 g−1. Galvanostatic measurements of dependences of cell voltage on time were performed in a static cell; capacitance of the electrodes was determined from the plateau of the curves. The capacitance of electric double layer was calculated. For the CH900 material, which is characterized by the highest volume of hydrophilic micropores and nanosized voids, this value achieves 63 F g−1. The model for capacitive deionization in a static cell has been developed; the approach allows one to calculate the process using only experimental parameters (surface conductivity and capacitance of electric double layer).