Synthetic batteries for the energy revolution: Chemists present an innovative redox-flow battery based on organic polymers and water -- ScienceDaily
'A team of researchers made a decisive step towards a redox-flow battery which is simple to handle, safe and economical at the same time: They developed a system on the basis of organic polymers and a harmless saline solution. The new redox-flow battery can withstand up to 10,000 charging cycles without losing a crucial amount of capacity.'http://www.sciencedaily.com/releases/2015/10/151021135628.htmAn aqueous, polymer-based redox-flow battery using non-corrosive, safe, and low-cost materials : Nature : Nature Publishing Group
'... 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.