LAUSR

Inverted capacitive deionization (i-CDI) is examined using microporous Spectracarb carbon electrodes in 10 mmol L–1 NaCl solution without deaeration. i-CDI testing shows that using conventional operational methods, i.e., Vch = 0.8 V and Vdis = 0 V (0.8/0 V), cannot stabilize salt separation after approximately 409 h with an averaged salt adsorption capacity (SAC) of 6.0 ± 0.8 mg g–1. The cycled anode possesses a collapsed cyclic voltammogram due to an increase in the sheet resistance by the formation of a surface oxide layer. This layer eventually suppresses electronic charge utilization in the i-CDI cell causing degraded salt separation. By analysis of potential distributions incorporated with the modified Donnan model, an improved i-CDI operational method is proposed by reducing Vch to 0.4 V and Vdis to −0.4 V (0.4/–0.4 V) while maintaining a voltage window (Vch–Vdis) of 0.8 V. The improved i-CDI testing demonstrates that not only is the separation process stabilized up to approximately 420 h but the SA...