Lithium metal batteries made usable with integrated flame retardant
Lithium metal batteries boast an energy density many times greater than lithium-ion batteries, but become unsafe when flammable gases are generated during thermal runaway. Chinese researchers have now found, as published in the scientific publication PNAS, that incorporating flame retardant interfaces (FRIs) into the cathode enables a smart response to thermal abuse, “significantly suppressing gas generation and altering gas composition.”
The researchers explain in their paper that FRIs reduce oxygen release at the cathode and alter the gas composition at the full-cell level, which helps lower flammability and prevents mechanical rupture. The research team claim that “the self-heating rate of the improved cells is reduced by 4 orders of magnitude, achieving zero thermal runaway in pouch cells.” The smart gas management strategy is said to enhance both thermal safety and electrochemical stability of lithium metal cells, offering a “transformative pathway to fire-safe Li metal batteries for advanced energy storage applications.”
Inserting a polymer into the battery’s cathode that releases fire-retardant chemicals when the temperature rises proved, under testing, that not only was the lithium metal battery able to withstand the same heat as a conventional lithium-ion battery, but was also able to withstand temperatures of up to 220 °C without catching fire at all, long after its lithium-ion counterpart had burst into flames.
The process, claim the researchers, can be integrated into lithium metal batteries with minimal changes to the production process, saying that the process could make this battery type with high energy density suitable for electric cars.
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