An aqueous, polymer-based redox-flow battery using non-corrosive, safe, and low-cost materials

• Autores: Tobias Janoschka, Norbert Martin, Udo Martin, Christian Friebe, Sabine Morgenstern, Hannes Hiller, Martin D. Hager, Ulrich S. Schubert
• Localización: Nature: International weekly journal of science, ISSN 0028-0836, Vol. 527, Nº 7576, 2015, págs. 78-81
• Idioma: inglés
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• Resumen

  • For renewable energy sources such as solar, wind, and hydroelectric to be effectively used in the grid of the future, flexible and scalable energy-storage solutions are necessary to mitigate output fluctuations1. Redox-flow batteries (RFBs) were first built in the 1940s2 and are considered a promising large-scale energy-storage technology1,3,4. A limited number of redox-active materials4,5,6,7,8,9,10—mainly metal salts, corrosive halogens, and low-molar-mass organic compounds—have been investigated as active materials, and only a few membrane materials3,5,11,12,13,14, such as Nafion, have been considered for RFBs. However, for systems that are intended for both domestic and large-scale use, safety and cost must be taken into account as well as energy density and capacity, particularly regarding long-term access to metal resources, which places limits on the lithium-ion-based and vanadium-based RFB development15,16. Here we describe an affordable, safe, and scalable battery system, which uses organic polymers as the charge-storage material in combination with inexpensive dialysis membranes, which separate the anode and the cathode by the retention of the non-metallic, active (macro-molecular) species, and an aqueous sodium chloride solution as the electrolyte. This water- and polymer-based RFB has an energy density of 10 watt hours per litre, current densities of up to 100 milliamperes per square centimetre, and stable long-term cycling capability. The polymer-based RFB we present uses an environmentally benign sodium chloride solution and cheap, commercially available filter membranes instead of highly corrosive acid electrolytes and expensive membrane materials.