Surface Property of High-Voltage Cathode LiNiPO₄ in Lithium-Ion Batteries: A First-Principles Study

In the initial development of lithium-ion batteries, the safety and cycle life of lithium-ion batteries were doubtful due to the unstable anode and cathode materials, so they could not effectively be used in commercial products. Cathode materials play an important role in Li-ion batteries because they decide the cell potential and capacity. In order to effectively solve the problem of poor electrical and ionic conductivity, doping with cations and modifying surface layers are common techniques applied to synthesizing olivine cathode materials. The dopant should be able to increase the transport efficiency of lithium ions which usually has different charge and size with cations to increase the lattice size and create sufficient defects. The density-functional theory is an important method in the first-principles calculation, it makes the solving of the multi-electron Schrodinger equation feasible by transforming the corresponding equation to the Kohn-Sham equation.