A new approach for prediction of cation ordering in mixed-metal oxide cathode materials

Development of new cathode materials with superior electrochemical properties is crucial for electric-vehicle applications using rechargeable batteries.[1] In this regard, mixed-transition metal oxide-based cathode materials, such as NCM cathode materials (Li[Ni_xCo_yMn_1-x-y]O₂), have received significant attention in recent years.[2] A detailed understanding of the atomic level structure is important in the development of new cathodes, as the electrochemical properties of these materials are affected by the arrangement of ions in the crystal lattice.[3,4] However, experimental determination of ionic arrangement is difficult, especially for materials consist of multiple metal ions. In this work, we present a new approach based on Monte Carlo (MC) simulated annealing (SA) to determine the most probable cation ordering from a myriad of possible configurations. The MCSA code developed here is implemented in the GULP program package.[5] In our approach, the cation ordering is generated randomly and are accepted using the Metropolis criteria in each annealing cycle and is minimized in each MC step. The above approach is also useful in predicting energetically favorable dopant cites and cation mixing energies. The new MCSA structure prediction approach is validated by studying some of the well-known NCM cathode materials.

References

1. Liu et al. Adv. Funct. Mater., 2012, 23, 929
2. Kim et al. Adv. Energy Mater., 2018, 8, 1702028
3. Seo et al., Nat. Chem., 2016, 8, 692
4. Harris et al., Chem. Mater., 2017, 29, 5550
5. Gale, J. D. and Rohl, A. L., Mol. Simul. 2003, 29, 291