>>This makes LiCoO2 batteries susceptible to thermal runaway in cases of abuse such as high temperature operation (>130 °C) or overcharging. At elevated temperatures, LiCoO 2 decomposition generates oxygen, which then reacts with the organic electrolyte of the cell. This is a safety concern due to the magnitude of this highly exothermic reaction, which can spread to adjacent cells or ignite nearby combustible material. In general, this is seen for many lithium ion battery cathodes.

https://en.m.wikipedia.org/wiki/Lithium_cobalt_oxide