A non-aqueous liquid electrolyte secondary cell, in which Li.sub.x MO.sub.2, where M is at least one transition metal, preferably at least one of Co and Ni , with 0.05.ltoreq.X.ltoreq.1.10, and in which charging and discharging is carried out by doping and release of lithium, is disclosed. The non-aqueous liquid electrolyte secondary cell has a current breaking device operated responsive to rise in the internal pressure in the cell. The current breaking device is adapted to be actuated positively by adding lithium carbonate to the active material of the positive electrode and providing the active material with surface portion covered with lithium carbonate. Preferably, the amount of addition and the specific surface area of lithium carbonate are 0.5 to 15 wt % and not less than 0.1 m.sup.2 /g, respectively.