Wednesday, 4 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
New cathode materials of Li-ion battery which realize large-reversible capacity are demanded urgently. Computational method is promising approach of material search and analysis. However, calculation of nonstoichiometric composition is technically difficult due to large degree of configuration freedom. To optimize structure with reasonable time, genetic algorithm (GA) is used in this study. To evaluate GA-derived structure, we used BV-FF calculations .
As an example, the variation of total energy of Li16Co16O32 for GA driven structures as a function of generation is shown in Fig.1. The structure framework is cation-disordered rocksalt-type structure and there are 32 cation site and degree of freedom of cation arrangement is 6×108. The red line indicates the lowest energy of GA generated structures among present and previous generations. Fig.2 shows the most stable structure obtained by GA. Green and blue colored octahedra correspond to LiO6 and CoO6, respectively. We confirmed the cation arrangement of most stable structure is layered rocksalt-type structure.
Reference  S.Adams et al, physica status solidi (a), 208(8), 1746-1753 (2011)