1. A new model on cation distribution in cation-disordered Li1+xTM1−xO2 cathodes.
- Author
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Huang, Yang, Liu, Long, Zhu, Yuanyuan, Gao, Min, and Zhang, Junrong
- Subjects
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MONTE Carlo method , *HEAT resistant materials , *TRANSITION metal oxides , *THERMAL equilibrium , *METALLIC oxides , *CATIONS - Abstract
The search for new materials that could improve the energy density of Li-ion batteries (LIB) is one of today's most challenging issues. Recently, cation-disordered lithium-excess metal oxides have emerged as a promising new class of cathode materials for LIB, due to their high reversible capacities and nice structural stability. However, a full structural model of the Li-transition metal (TM) sharing sublattice and the origin of short range ordering (SRO) of cations requires further investigation. In this work, we put forward a Monte Carlo strategy of building cation-disordered rocksalt material supercell models. The cations of Li 1.0 Ti 0.5 Ni 0.5 O 2 (LTNO) are placed at the FCC sublattice sites with the constraint of Pauling's electroneutrality rule, instead of a random way. This constraint causes the Li-Ti and Ni-Ni clustering. Based on this model, we discussed the relationship between the SRO, the local distorting, the theoretical capacity and the order-disorder strengths. A unified understanding of these factors in cation-disordered materials may enable a better design of disordered-electrode materials with high capacity and high energy density. • In this work, we described a Monte Carlo strategy to build the model of cation-disordered material Li 1.0 Ti 0.5 Ni 0.5 O 2. The cations are distributed at the FCC sublattice with a constraint of Pauling's electroneutrality rule, instead of a random way. The model is relaxed by an atomistic force field to get into the thermal equilibrium. • We conclude that the electroneutrality causes the short-range ordering (SRO) in the cation sublattice and results the Li-Ti and Ni-Ni clustering. • The SRO is favoured by the lattice completeness and lower the local distortion of the cations. But it also decreases the content of 0-TM channels and the capacities of the materials. So we can expect for a more 'disordered' material with larger capacity. The energy calculation shows that this can be done by sintering the materials at higher temperatures which has been proved by several experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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