Improvement of 12 V overcharge behavior of LiCoO_2 cathode material by LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 addition in a Li-ion cell

摘要

The 12 V overcharge instability of the LiCoO_2 cathode material was improved by the physical blending it with LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2. Even though a Li-ion cell containing a LiCoO_2 cathode did not exhibit thermal runaway at 12 V at the 1 C overcharging rate, it showed thermal runaway at the 2 C overcharging rate, and the cell surface temperature reached more than 400℃. However, the LiCoO_2 cell containing 40,50, and 60 wt.% LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 did not exhibit thermal runaway at the 2C overcharging rate. In conclusion, 60wt.% LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 in the LiCoO_2 cathode showed the lowest cell surface temperature of < 90℃ even at a 3 C overcharging rate.