Screening Topological Quantum Materials for Na-Ion Battery Cathode

Recent studies have suggested that more than 27% of existing materials are topological and exhibit intrinsically high electrical conductivity with high stability protected by topology, which can meet the requirement that the battery cathode needs to be conductive not just ionically but also electronically for the high rate performance. In this work, using machine learning and first-principle calculations, for the first time we have screened 7386 topological quantum materials with low diffusion energy barriers. Especially, topological semimetal Na4CoO3 has been identified to exhibit high reversible capacity of 269.5 mAh/g and high energy density of 746.5 Wh/kg. Furthermore, Na4CoO3 also exhibits good compatibility with many sodium metal oxides solid electrolyte such as Na3PO4 and NaAlO2. These findings suggest that Na4CoO3 can be a novel high performance Na-ion battery cathode material going beyond the conventional ones.