High performance concentration capacitors with graphene hydrogel electrodes for harvesting salinity gradient energy. Issue 12 (31st January 2018)

• Record Type: Journal Article
• Authors: Zhan, Fei; Wang, Zijian; Wu, Tingting; Dong, Qiang; Zhao, Changtai; Wang, Gang; Qiu, Jieshan
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 12(2018)
• Page Start: 4981
• Page End: 4987
• Publication Date: 2018-01-31
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7ta11070g
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Concentration capacitors with graphene hydrogel electrodes are proposed to efficiently harvest salinity gradient energy. Abstract : Salinity gradient energy (SGE) is the energy available from the salinity difference between freshwater and saltwater. Herein, we propose a concentration capacitor as a novel capacitive mixing (CapMix) technique to harvest SGE. The concentration capacitor comprises identical electrodes and a membrane that separates concentrated and diluted solutions that alternately flow through the capacitor. Graphene hydrogel (GH) electrodes and a filtration membrane (FM) or an anion exchange membrane (AEM) are used to construct GH//FM//GH and GH//AEM//GH concentration capacitors. These concentration capacitors show excellent performance in harvesting SGE, particularly the GH//AEM//GH concentration capacitor, whose voltage rise and average power density can reach 288.5 mV and 482.4 mW m −2, respectively, which are higher than those obtained with other CapMix techniques. The outstanding performance is associated with the double-channel construction, the membrane potential, and the macroporous structure and abundant negative charge of the GH electrodes. Our results show that the concentration capacitor is a promising approach for efficiently extracting SGE.