The research is reported in the journal Nature Materials in a paper by MIT postdoc Yan Wang, visiting professor of materials science and engineering Gerbrand Ceder, and five others. The researchers describe a new approach to the development of solid-state electrolytes that could simultaneously address the greatest challenges associated with improving lithium-ion batteries, the technology now used in everything from cellphones to electric cars.
The electrolyte in such batteries - typically a liquid organic solvent whose function is to transport charged particles from one of a battery’s two electrodes to the other during charging and discharging - has been claimed to be responsible for the overheating and fires that, for example, resulted in a temporary grounding of all of Boeing’s 787 Dreamliner jets. The researchers are the first to show that this can be done in a formulation that fully meets the needs of battery applications.
Solid-state electrolytes could be “a real game-changer,” claims Ceder, creating “almost a perfect battery, solving most of the remaining issues” in battery lifetime, safety, and cost.
Costs have already been coming down steadily, he says. But as for safety, replacing the electrolyte would be the key. Ceder said: “All of the fires you’ve seen, with Boeing, Tesla, and others, they are all electrolyte fires. The lithium itself is not flammable in the state it’s in in these batteries. [With a solid electrolyte] there’s no safety problem - you could throw it against the wall, drive a nail through it - there’s nothing there to burn.”
The proposed solid electrolyte also holds other advantages. “With a solid-state electrolyte, there’s virtually no degradation reactions left,” explained Ceder which means the solid-state batteries could last through “hundreds of thousands of cycles”.
According to Ceder the key was finding solid materials that could conduct ions fast enough to be useful in a battery.