After the story with numerous spontaneous flares Samsung Galaxy Note 7 and their subsequent recall from the market, many smartphone manufacturers have reflected: how would we protect our users and themselves from similar situations in the future? The answer to this question was found by scientists from Stanford University. They proposed to initially supply the lithium-ion battery with an integrated system capable of instantly extinguishing the ignition that had started and avoiding a possible explosion.
Researchers looked at many options for realizing their idea. The introduction of flame-retardant substances into Li-Ion would inevitably reduce the conductive capacities of electrochemical cells, so this approach had to be abandoned at once. Then scientists came up with a brilliant idea: if you isolate flame-retardant substances from the contents of cells, deterioration of the characteristics of the battery can be avoided. In all, it is necessary to enclose molecules of matter in polymer capsules, the shell of which is destroyed only at high temperature.
As soon as the battery is close to the explosion, the shell of the capsules will be destroyed, and the flame-retardant contained in them will extinguish the fire. In the studies, scientists used as a “fire extinguisher” triphenyl phosphate, coated with a polymer PVDF-HFP. From the moment of the artificially created battery overheating to a full stop of ignition, no more than a second passed. At the same time, the performance of the battery has not decreased. But before scientists there is one more serious problem: the longevity of flame-retarding capsules leaves much to be desired. After 360 cycles of recharging, the polymer shell of some capsules is destroyed and reduces the efficiency of the battery.