Capacitive deionization (CDI) operated under inverted mode involves electronic charging and discharge steps with corresponding ion concentration and desalting coupled with simultaneous energy storage. In this work, an energy recovery system derived from a Ćuk dc-dc converter is explored to transfer the energy stored from one inverted capacitive deionization (i-CDI) cell during the electronic discharge step to another during the charge step, decreasing the overall energy requirement for capacitive water desalination. The i-CDI cell, a subset of CDI architecture operated in an inverted mode, is improved by incorporating ion-selective membranes to allow inverted membrane capacitive deionization (i-MCDI), leading to enhanced charge storage achieved with reduced energy input. For example, in comparison to i-CDI that requires ∼12 J g-1 of energy input, the i-MCDI cell requires only 8 J g-1. By incorporating the recovery system, the energy penalty can be reduced to only require ∼8 and 4 J g-1 for i-CDI and i-MCDI cells, respectively. Improvement in energy recovery was shown to be achieved by reducing charge leakage, with the i-MCDI cell showing up to 3 times the leakage resistance of the i-CDI cell.
|Number of pages
|Environmental Science: Water Research and Technology
|Published - Feb 2020
Bibliographical noteFunding Information:
The authors are grateful to the U.S.–China Clean Energy Research Center, U.S. Department of Energy for project funding (No. DE-PI0000017). The authors also thank Mr. R. Perrone for help in designing and constructing the i-CDI and i-MCDI cells.
© 2020 The Royal Society of Chemistry.
ASJC Scopus subject areas
- Environmental Engineering
- Water Science and Technology