A Unique Structure of Ni(III) in LiNi[sub 0.3]Co[sub 0.7]O[sub 2] Without Jahn-Teller Distortion

We examined the oxidation state and atomic structures of Ni and Co in and compared them with those of and . The X-ray absorption near-edge structure and extended X-ray absorption fine structure results show that Ni (primarily) and Co are present with an oxidation state of . Ni(III) in has a distorted octahedral coordination due to an active Jahn-Teller effect as shown previously. However, Ni(III) in has a regular octahedral coordination with six oxygen atoms at a distance of and, hence, the Jahn-Teller effect is inactive. The oxidation state and local atomic structure of Co in are similar to those of .