High flammability has been the biggest problem that needs to be solved for lithium-ion batteries. A few days ago, a research team in Stanford University made a breakthrough by developing a non-flammable electrolyte that prevents the battery from catching fire even when exposed to flame. The researchers solved the long-standing safety issue associated with lithium-ion batteries by using a simple tactic: adding more salt.
Heat is generated during the operation of a battery, in which the electrolyte is a flammable liquid, posing a fire risk to smartphones, laptops, EVs and other electronics powered by lithium-ion batteries. To solve this problem, scientists have proposed numerous solutions including integrated fire retardants, overheat warning systems and emergency shutdown procedures. Some of them have also worked around electrodes and electrolytes.
Battery electrolytes enable electrical charges to pass between the anode and cathode. However, the defects within the battery and temperature rise during operations will inflate the electrolyte. When the temperature hits around 60°C, the electrolyte solvent starts to evaporate and transforms from liquid to gas, which is likely to catch fire.
Accordingly, Stanford University partnered with the US Department of Energy’s SLAC National Accelerator Laboratory to develop a non-flammable battery that can work at high temperatures. Specifically, the proposed polymer electrolyte comprises abundant LiFSI, accounting for 63% of total weight. It was paired with flammable solvent molecules, with the two forming a symbiotic relationship, thereby guaranteeing battery safety and performance.
The solvent molecules in the electrolyte conduct ions, while the highly concentrated salt “anchors” these molecules to prevent them from evaporating, eliminating the possibility of the battery catching fire. The research team also conducted an experiment on the proposed battery and demonstrated that it can function safely at a maximum ambient temperature of 100°C. Rachel Z Huang, first author of the paper proposing the electrolyte, specified that the greatest challenge facing the battery industry is safety, for which people have spared no effort to develop safe battery electrolytes.
On top of that, the new electrolyte is as gooey as conventional electrolytes, exemplifying its compatibility with commercially available battery components, which is different from other non-flammable experimental electrolytes. Yi Cui, another author of the paper, said that the novel electrolyte is compatible with the existing lithium-ion battery technologies and that it will exert great impact on consumer electronics and electrical transportation.
(Image credit: SLAC)