Comparison of cathode behavior of lithium and sodium batteries and properties related to voltage and density

Major advances in rechargeable batteries for portable electronics and large-scale grid storage will depend on the discovery and exploitation of new high performance materials, which requires a greater fundamental understanding of their properties on the atomic and nanoscopic scales. This review describes some of the exciting progress being made in this area through use of computer simulation techniques, focusing primarily on positive electrode (cathode) materials for lithium-ion batteries, but also including a timely overview of the growing area of new cathode materials for sodiumion batteries. In general, two main types of technique have been employed, namely electronic structure methods based on density functional theory, and atomistic potentialsbased methods.The scope of contemporary work is highlighted by studies of a broad range of topical materials encompassing layered, spinel and polyanionic framework compounds such as LiCoO, LiMn O, and LiFePO respectively. Fundamental features important to cathode performance are examined, including voltage trends, ion diffusion paths and dimensionalities, intrinsic defect chemistry, and surface properties of nanostructures.