Surface conductivity measurements for porous carbon electrodes

A method for measuring the surface conductivity in porous electrodes was developed. The knowledge of surface conductivity is very important for simulation and optimization of the capacitive deionization of aqueous solutions, which is a new promising and economical method for water desalination. The surface conductivity (SC) is the tangential (longitudinal) conductivity of a double electric layer (DEL). The SC involves the conductivity induced by the conductivity of the counterions of the surface groups in a highly disperse carbon electrode κ_sg and the surface conductivity κ_sch induced by the electrostatic charge of the inner surface of the electrode pores and the charge-compensating ions of the solution, i.e., the classical DEL. The value of κ_sg depends on the concentration of the surface groups C _sg on carbon, i.e., their exchange capacity, and κ_sch depends on the potential E. SC measurements were performed on activated porous carbon electrodes CH900 and SAIT. This SC measurement procedure is another method for studying DEL.