Development of New Redox Flow Battery Systems

Concerns over the environmental consequences of burning fossil fuels and their remaining reserves have led to an increasing use of renewable energy generated from sources such as solar and wind. However, the intermittent, varied nature of the renewable resources makes it difficult to integrate these valuable energies into the electrical grids. A solution to this problem is to employ large-scale electrical energy storage (EES), which is widely considered as an effective approach to improve the reliability, power quality, and economy of these renewable energies. Among the most promising large-scale EES technologies are the redox flow batteries (RFBs). RFBs are special electrochemical systems that can repeatedly convert and store multi-megawatt-hours (MWhs) of electricity energy to chemical energy and convert the chemical energy back to electricity energy when needed. The advantages of RFBs include short response time, low self discharge, long life-time, and independent tunable power and storage capacity, which make it possible to independently scale up the electricity storage capacity and power generation capacity.  With the support of US Department of Energy’s Office of Electricity, PNNL has carried out extensive efforts in the development of advanced redox flow batteries. Substantial progress has been achieved in the past two years, including two new redox chemistries (V-Fe system and all vanadium mixed acid system), which will be reported in this presentation