Investigating improvements on redox flow batteries

Abstract

As fossil fuel resources become depleted and concerns about global warming increases, focus on renewable energy sources will become more urgent. The problem however is the intermittent nature of these sources, which necessitates the need for energy storage devices coupled to most of their applications. Lead-acid batteries have long been used as the most economical option to store electricity in many small scale applications, but lately more interest have been shown in redox flow batteries. The low power densities of redox flow batteries however limit their application to large-scale storage and mostly stationary use, while costs still favour lead-acid batteries. Studies done at the CSIR have identified possible redox couples that could be used in a redox flow battery that not only reduces the costs significantly, but would also improve the power densities of the battery itself, thus broadening the market applications for redox flow batteries. Preliminary results thus far have indicated that these new couples could provide a battery that competes well with the current commercially available redox flow batteries. Further testing is still underway to optimise the battery parameters, determine battery lifetime as well as determining the efficiencies during long cycling.