Lithium-ion batteries power our smart phones, tablets, laptops, and, in the next future, electric cars. However, these highly efficient and effective energy storage devices may be affected by some flammability risk due to the employment of organic solvents in electrolyte. The presence of volatile, low flash point organic solvents, in fact, increases the risk of fire in case of outside- and inside-the-cell malfunctions.
Italian and German researchers directed by Professor Jusef Hassoun at the University of Ferrara (Ferrara, Italy) and Professor Stefano Passerini at the Helmholtz Institute Ulm of Karlsruhe Institute of Technology (Ulm, Germany), with the financial support of the BMW Group, have addressed this issue with remarkable results. The researchers replaced the organic solution in the lithium-ion battery by a room temperature molten salt (also known as ionic liquid), thus realizing organic solvent-free electrolytes. The absence of volatile, low flash point organic solvents substantially improves the fire resistance of the battery.
Ionic liquids have been proposed since long-time as flame resistant electrolyte components. However, the long-term performance of lab-scale batteries using ionic liquid-based electrolyte has been proved only recently. The cell developed is capable of thousands of charge-discharge cycles without any decay as reported in the high ranking journal "Energy & Environmental Science" of the Royal Society of Chemistry in 2016.
Stefano Passerini, 29.09.2016