According to a news release from Imperial College London, a novel battery architecture might enable more inexpensive long-term energy storage. Engineers and chemists at Imperial College London created a polysulfide-air redox flow battery (PSA RFB) with two membranes. This dual membrane design addresses some of the shortcomings of PSA RFB, allowing it to be utilized to store surplus renewable energy for extended periods of time.
The researchers explained their quest for a substitute for the electrolyte vanadium used in traditional redox flow batteries, which are often pricey and mostly obtained from China or Russia. To begin, they chose a liquid electrolyte, polysulfide, and a gas electrolyte, air.
Their polysulfide-air batteries, on the other hand, were constrained by the fact that no membrane could support chemical processes while also keeping the liquid electrolyte from crossing over to the opposite side of the cell.
“If the polysulfide crosses over to the airside, you lose material from one side and impede the activity of the catalyst on the other,” said Dr. Mengzheng Ouyang of Imperial College, who collaborated on the research. “This degrades the battery’s performance — this was an issue we wanted to fix.”
A novel strategy for long-term energy storage (battery)
The researchers devised an alternate method, separating the polysulfide from the air using two membranes that held a solution of sodium hydroxide between the two portions of the cell. All of the materials are inexpensive and widely available, and the team noted that there is still room for experimentation to identify even more affordable materials that perform similarly.
The Imperial team discovered that its polysulfide-air redox flow battery delivered up to 5.8 milliwatts per centimeter squared, with an energy cost of around $2.5 per kilowatt-hour. The power cost — the difference between the rate of charge and discharge and the cost of materials — was around $1,600 per kilowatt. While this is too high for long-term storage, the researchers think they can significantly reduce the power cost.
“To make this economically viable for large-scale storage, just a very little performance boost is necessary,” stated Professor Nigel Brandon, who worked on the study as well. This might be accomplished “by increasing the activity of the catalyst or by further improving the membranes utilized.”
The Imperial team’s innovation addresses a critical need for novel kinds of energy storage as the globe transitions to a renewable energy future, as outlined in the current IPCC assessment, which warns of severe implications if necessary efforts to substantially cut humanity’s global carbon footprint are not implemented.