Combinatorial computational chemistry approach to the design of cathode materials for a lithium secondary battery

Abstract

Combinational chemistry is an efficient technique to find materials with novel properties by synthesizing and screening a large number of compounds in a short time. Recently, we introduced the concept of combinational approach into computational chemistry and proposed a novel approach, “combinatorial computational chemistry”. In the present study, we applied combinatorial computational chemistry to investigate the structural properties of lithium transition metal oxides, LiMO 2 (M=3d transitional metal), with a layered rocksalt structure. LiMO 2 is a promising material as positive electrodes in rechargeable lithium batteries. Density functional calculations on periodic models were performed to investigate the structural properties of LiCoO 2, LiNiO 2, and doped LiNiO 2, revealing that the poor charge–discharge cyclic reversibility of LiNiO 2 resulted from the large change in the structure due to the difference in the bond length between Ni 3+–O and Ni 4+–O. The analysis of the structural properties of Li 0.66Ni 0.5Me 0.5O 2 (Me=dopant) revealed that doping with Co decreased the change in the structure of LiNiO 2 during cycling. Doping of Ni with Al was also found to stabilize LiNiO 2.