Researchers from Politecnico di Milano have created a polymer electrolyte in the form of a semi-solid gel membrane that does not burn and allows fluoride ions (charged particles) to move inside a battery at ordinary room temperature. The work was published in the journal Energy Storage Materials.
The new material is described for the first time as a fluoride exchange membrane (FEM), by analogy with the widely used proton exchange membranes (PEM) and anion exchange membranes (AEM).
The main advantage of fluoride-ion batteries is their potentially higher theoretical energy density. According to Professor Luca Magagnin, this is roughly 600 watt-hours per kilogram versus 150-250 for standard lithium-ion batteries. "In practice this would mean roughly twice the range: an electric car could travel twice as many kilometers," he explained. However, this is a calculated figure for a laboratory development, not a characteristic of a finished product.
In addition, fluoride-ion cells can be lighter and safer: the membrane does not ignite, which reduces the risk of fire. This is especially important for energy storage systems, which are needed to smooth out peaks in renewable generation. "Peaks in renewable energy production do not coincide with peaks in consumption. European countries are developing storage systems, but their mass adoption is hampered by concerns about battery fire hazards," noted project coordinator Maurizio Sansotera.
Another key point: unlike previous generations of fluoride-ion batteries, which required heating to 100-150 degrees to increase ionic conductivity, the new membrane works at room temperature. This makes it possible to avoid spending energy on preheating, Professor Giuseppina Raffaini emphasized.
The study was interdisciplinary and brought together specialists in chemistry, materials science, electrochemistry and molecular dynamics. For now this is a laboratory result, and no timeline for commercial application has been reported.