Lithium ion battery is widely used in electric cars, smart phones and other aspects. In pursuit of higher performance, manufacturers also attach great importance to battery safety. Scientists in Japan have come up with a new electrolyte that could improve the battery safety at higher voltages.

The research was carried out by a team of scientists at the university of Tokyo (UT) who focused on the electrolyte part of the battery. The solution can carry lithium ions back and forth between the battery's electrodes during charging and discharging, and by replacing the solvents used in mainstream batteries, it can achieve safe, highly stable operation and high voltage performance, which is better than most existing lithium ion batteries.

Professor dunxiong yamada, a researcher at the university of Tokyo said, the battery's voltage was mainly limited by the electrolyte material. The current electrolyte solvents in lithium ion battery still use the same solvents that were first commercialized in the early 1990s.So wefound a way to improve. Our new fluorinated cyclic phosphate solvent (TFEP) electrolyte greatly improves the existing ethyl carbonate(EC).

The team designed the cyclic phosphate-based electrolyte by combining the chemical structure of the conventional electrolyte solvent ECwith the flame retardant. This provides the phosphate properties of both two molecules, including the high pressure resistance of the solvent and the non-flammability of the flame retardant, which minimises the risk of lithium batteries catching fire.

When synthesizing electrolytes, the researchers found that the most effective formulation contained 0.95 M LiN(SO2F)2 in TFEP / 2,2, 2-trifluoroethyl methyl carbonate. This particular component is capable of synthesizing an electrolyte with noncombustibility and zero self-extinguishing time and stable operation of graphite anode and high pressure LiNi0.5Mn1.5O4 anode.

Unexpectedly, yamada said, the new electrolyte solvent could increase battery voltage from the current 3.8v to 4.6v and extend battery life.