Carbonized peat moss electrodes for efficient salinity gradient energy recovery in a capacitive concentration flow cell

Haihui Zhu, Wangwang Xu, Guangcai Tan, Elizabeth Whiddon, Ying Wang, Christopher G. Arges, Xiuping Zhu

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The globally extractable salinity gradient (SG) energy from the mixing of seawater and river water is estimated to be 3% of worldwide electricity consumption. Here we applied carbonized peat moss (CPM) electrodes to a capacitive concentration flow cell that is capable of harvesting SG energy based on the capacitive double layer expansion (CDLE) together with the Donnan potential. The electrodes were made from the visually inexhaustible peat moss by a facile and environmental benign pyrolysis process. With two identical CPM electrodes and a cation-exchange membrane, the cell produced a peak power density of 5.33 W m−2 and an average power density of 950 mW m−2, the highest ever reported for CDLE-based techniques, using synthetic seawater (30 g L−1 NaCl) and river water (1 g L−1 NaCl). The excellent performance was a result of the macroporous structure of the CPM electrodes, the assistance of Donnan potential, and the double-channel structure of the cell. This system was durable as it could extract energy from highly saline water (300 g L−1 NaCl) and it still worked well after 100 cycles. This study provides a new method to efficiently and continuously harvest SG energy based on the CDLE without an external charge.

Original languageEnglish (US)
Pages (from-to)240-248
Number of pages9
JournalElectrochimica Acta
StatePublished - Jan 20 2019

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Electrochemistry

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