Surveying Manganese Oxides as Electrode Materials for Harnessing Salinity Gradient Energy
Autor: | Christopher A. Gorski, Bruce E. Logan, Huichun Zhang, Jenelle Fortunato, Jasquelin Peña, Mengqiang Zhu, Sassi Benkaddour, Jianzhi Huang |
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Rok vydání: | 2020 |
Předmět: |
Manganese
Salinity Materials science Sodium Inorganic chemistry chemistry.chemical_element Oxides General Chemistry 010501 environmental sciences 01 natural sciences 7. Clean energy Redox 6. Clean water Electrochemical cell Ion chemistry Manganese Compounds Electrode Environmental Chemistry Cyclic voltammetry Electrodes 0105 earth and related environmental sciences |
Zdroj: | Environmental sciencetechnology. 54(9) |
ISSN: | 1520-5851 |
Popis: | The potential energy contained in the controlled mixing of waters with different salt concentrations (i.e., salinity gradient energy) can theoretically provide a substantial fraction of the global electrical demand. One method for generating electricity from salinity gradients is to use electrode-based reactions in electrochemical cells. Here, we examined the relationship between the electrical power densities generated from synthetic NaCl solutions and the crystal structures and morphologies of manganese oxides, which undergo redox reactions coupled to sodium ion uptake and release. Our aim was to make progress toward developing rational frameworks for selecting electrode materials used to harvest salinity gradient energy. We synthesized 12 manganese oxides having different crystal structures and particle sizes and measured the power densities they produced in a concentration flow cell fed with 0.02 and 0.5 M NaCl solutions. Power production varied considerably among the oxides, ranging from no power produced (β-MnO2) to 1.18 ± 0.01 W/m2 (sodium manganese oxide). Power production correlated with the materials' specific capacities, suggesting that cyclic voltammetry may be a simple method to screen possible materials. The highest power densities were achieved with manganese oxides capable of intercalating sodium ions when their potentials were prepoised prior to power production. |
Databáze: | OpenAIRE |
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