Prediction of Manganese-rich phases from NiMnCoCO3 structure before lithiation, for cathodes in lithium-ion batteries: Cluster expansion study

Abstract

Manganese-rich (Mn-rich) cathode materials have emerged as viable possibilities for lithium-ion batteries that are both safe and high in energy density. These cathode materials have higher energy densities and better electrochemical performances than conventional cathode materials, making them suitable for a wide range of applications, including portable devices, electric cars, and grid storage systems. This study focuses on the use of Universal cluster expansion (UNCLE) method to determine stable Mn-rich phases with minor concentrations of nickel (Ni) and cobalt (Co). Cluster expansion managed to generate five Mn-rich stable phases which were further explored by calculating their structural properties, electronic properties, mechanical properties and vibrational properties. The structural properties indicated that the generated phases are triclinic systems and thermodynamically stable due to the negative formation energies observed, while the electronic property results indicated metallic behaviour for all the generated phases due to no energy band gap observed at the fermi line. On the other hand, mechanical properties indicated that three phases were found to satisfy the triclinic stability conditions leading to mechanical stability while two other phases were found to be mechanically unstable due to stability criteria not satisfied.