Tuning Li_(3)PO_(4)modification on the electrochemical performance of nickel-rich LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)

摘要

Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content.To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical performance of the nickel-rich cathode material,the surface of nickel-rich LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode material is decorated with the stable structure and conductive Li_(3)PO_(4)by a facile method.The LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)-1wt%,2wt%,3wt%Li_(3)PO_(4)samples deliver a high-capacity retention of more than 85%after 100 cycles at 1 C under a high voltage of 4.5 V.The effect of different coating amounts(0-5wt%)for the LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode is analyzed in detail.Results show that 2wt%coating of Li_(3)PO_(4)gives better performance compared to other coating concentrations.Detailed analysis of the structure of the samples during the charge−discharge process is performed by in-situ X-ray diffraction.It is indicated that the modification for LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode could protect the well-layered structure under high voltages.In consequence,the electrochemical performance of modified samples is greatly improved.