Advantages of Simultaneous Substitution of Co in LiNi_1/3Mn_1/3Co_1/3O_2 by Ni and Al

摘要

Ni and Al can be substituted for Co in LiNi_1/3Mn_1/3Co_1/3O_2 by increasing y and z in x LiNi_1/3Mn_1/3Co_1/3O_2-y LiNi_2/3Mn_1/3O_2-z LiNi_1/3Mn_1/3A1_1/3O_2 (x + y + z = 1) pseudoternary solid solution systems. Additions of Al improve the thermal stability of the charged positive electrode material, at a cost of capacity reduction, which can be at least partially recovered by the addition of Ni. The composition LiNi_(1/3+0.07)Mn_i/3Co_(1/3-0.2)Al_0.13O_2 (x = 0.4, y = 0.2, z = 0.4) shows excellent thermal stability compared to LiNi_1/3Mn_1/3Co_1/3O_2, but similar specific capacity. The samples were synthesized via a coprecipitation-based synthetic method to prepare a mixed hydroxide precursor, followed by sintering with a Li salt. Such materials may find application in large-size Li-ion batteries targeted for vehicle applications.