Solid state electrochemistry of intercalation compound of LiAl1/2Ni1/2O2 (R(3)over-bar-m) for lithium-ion batteries

One-to-one mixture of LiNiO2(R (3) over bar m) and alpha-LiAlO2(R (3) over bar m) in a solid matrix was prepared and examined in nonaqueous lithium ce lls. The sample was identified by XRD as a solid solution of LiNiO2 and alp ha-LiAlO2, i.e., LiA(1/2)Ni(1/2)O(2) (R (3) over bar m; a = 2.838 Angstrom, c = 14.226 Angstrom in hexagonal setting). Rechargeable capacity was about 100 mAh.g(-1) based on sample weight out of 164 mAh.g(-1) of theoretical c apacity. Capacity retention of the cell was good when it operated in voltag es between 2.5 and 4.5 V. XRD examinations indicated that the reaction proc eeded in a single phase over the entire range in Li1-xAl1/2Ni1/2O2 (0 less than or equal to x < 1/2) The solid-state redox reaction was also examined using the concept of electrochemical density of states, and the effect of a luminum on the solid-state redox levels primarily derived from redox specie s based on nickel was described.