Submillimeter wave ESR of Li1-xNi1+xO2 powder samples have been perfor
med from 90 to 383 GHz with the field up to 15 T. The samples with 1 -
x = 0.996, and 0.946 were measured. The 1 - x = 0.946 sample, which w
as investigated in the early studies, showed different ESR results fro
m those of nearly stoichiometric samples.