Asymmetric electrode configuration for enhanced membrane capacitive deionization

Ayokunle Omosebi, Xin Gao, James Landon, Kunlei Liu

Research output: Contribution to journalArticlepeer-review

173 Scopus citations

Abstract

Long-term performance of capacitive deionization (CDI) and membrane-assisted capacitive deionization (MCDI) single cells equipped with the same pristine carbon xerogel (CX) electrodes configured as the anode and cathode was investigated. Unlike CDI, which was subject to performance degradation in a short period of time, MCDI showed performance preservation during the 50 h of operation due to its ability to mitigate charge leakage from parasitic electrochemical reactions that result in carbon oxidation. Differential capacitance measurements of the used CDI and MCDI electrodes revealed shifting of the potential of zero charge (E PZC ) of the CDI anode from -0.1 to 0.4 V but only to 0.1 V for the MCDI anode. CDI and MCDI cells tested with electrodes having E PZC s at -0.1 and 0.5 V showed strongly contrasting results depending on the anode-cathode E PZC configuration. The MCDI cell configured with a 0.5 V E PZC cathode and -0.1 V E PZC anode displayed the best performance of all the tested cells, benefiting from increased counterion excess within the potential window, and the membrane was in-place to reject expelled co-ions from accessing the bulk.

Original languageEnglish
Pages (from-to)12640-12649
Number of pages10
JournalACS Applied Materials and Interfaces
Volume6
Issue number15
DOIs
StatePublished - Aug 13 2014

Keywords

  • capacitive deionization
  • carbon degradation
  • carbon xerogel
  • electrochemical impedance spectroscopy
  • ion-exchange membranes
  • potential of zero charge

ASJC Scopus subject areas

  • General Materials Science

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