Surface Modification of LiSr[sub 0.002]Ni[sub 0.9]Co[sub 0.1]O[sub 2] by Overcoating with a Magnesium Oxide

Commercially obtained LiSr 0.002 Ni 0.9 Co 0.1 O 2 was modified by overcoating its surface with MgO . As the surface was modified, onset temperature of thermal dissociation was increased about 10 ° C , and heat dissipation during thermal decomposition was diminished to a substantial extent. Lithium‐ion batteries whose cathodes were made from the surface‐modified LiSr 0.002 Ni 0.9 Co 0.1 O 2 exihibited improved performance, especially at the demanding rate of 1 C . Tendency toward explosion in the cylindrical battery was largerly alleviated by the surface treatment, even though the safety rating has not yet reached the industrial criterion.