Lithium ion batteries are at the heart of the consumer electronics we use every day, but the inconvenient side is that, they occasionally burst into flames. Now, scientists have found they can replace the unstable chemicals in batteries with an exceptionally stable polymer.
Like most discoveries, they were originally working on a project for a material that would keep marine life from adhering to the hulls of ships, but it led down a different path.
While testing the material, the team realized they could dissolve lithium salt and PEG, an indicator needed to produce conductivity in batteries.
Lithium-ion batteries create power by moving ions from the negative to the positive electrode when it re-charges; the ions go the opposite direction. The plain lithium batteries like the AAs in your remote control can only discharge. To recharge, li-ion batteries require an electrolyte, typically an ion-rich liquid like dimethyl carbonate (DMC), which is flammable even at room temperature.
They found that another polymer electrolyte PEG, and PFPE could combine to dissolve salt, and potentially function as an electrolyte.
When the team attached the PFPE to dimethyl carbonate, an electrolyte traditionally used in batteries, the resulting PFPE-DMC was a polymer that could move a battery's ions with insane levels of efficiency while remaining stable.
Everyone's been working on "The holy grail in batteries is a lithium-air battery, which has the power density equivalent to a fuel tank," but one of the linchpins is that [regular] electrolytes aren't compatible with oxygen." With the application of the new PFPE electrolyte, this type of power-dense battery might actually be possible.
While the lithium-ion batteries in a smartphone are small and used for a comparatively short ownership period, blowing up is rarely an issue. The team's testing shows that a PFPE electrolyte can remain stable down to at -90 degrees Celsius and up to 200 degrees Celsius. An electrolyte that doesn't catch fire or freeze could blow open doors for more applications. It would also mean a battery that wouldn't freeze in a very cold winter. Commercial appearances of this electrolyte are – as with most radical discoveries – still years away.