Patent ID: 7648693

Claim:
A cathode active material comprising: a storage stable lithium transition metal oxide of the general formula Li x ((Ni 1−a−b (Ni 1/2 Mn 1/2 ) a CO b ) 1−k A k ) 2−x O 2 , wherein 0.65≦a+b≦0.85, 0.1≦b≦0.4, A is a dopant, 0≦k≦0.05, and 0.95≦x≦1.05, said lithium transition metal oxide being substantially free of soluble bases such that less than about 20 ml of 0.1M HCl is necessary to titrate 200 ml of a solution containing substantially all of the soluble bases present in 10 g of said lithium transition metal oxide to a pH less than 5, said solution being prepared by repeated soaking and decanting of said lithium transition metal oxide.