Effect of Li1.3Al0.3Ti1.7(PO4)3 coating on the interfacial activity and stability of high-voltage LiNi0.6Co0.1Mn0.3O2/electrolyte
LiNi0.6Co0.1Mn0.3O2(NCM613)is one of the important research directions for lithium-ion battery cathode materials in recent years with acceptable safety performance,good cyclic stability,lower raw material and processing costs,and the ability to achieve energy density comparable to high Ni NCM(Ni＞80％,NCM811)by increasing the charging voltage.However,NCM613 suffers from serious side reactions with the electrolyte under high voltage charging state,causing a decrease in interfacial activity and stability,and then resulting in a series of problems such as capacity decay,gas generation,and safety hazards in the battery.Surface coating has been considered as the most effective approach which can effectively improve the interface stability of NCM613/electrolyte.Of the various coating materials,oxide coating layers can prevent interface side reactions between electrolyte and cathode materials,reduce the dissolution of transition metal ions,but typically cannot provide Li transport channel at the interface,resulting in degradation of capacity,rate,and cycling performance.In order to improve the interfacial activity and stability between NCM613 and electrolyte,Li1.3 Al0.3Ti1.7(PO4)3(LATP)was coated on NCM613 by liquid-phase method and the effects of coating amount and heat treatment temperature were studied.LATP coating effectively improve the capacity,rate,and cycling performance of cathode materials,and significantly enhances their thermal stability for cathode materials under high voltage.NCM613 exhibits optimal performance when the coating amount is 0.8％and the annealed temperature is 500 ℃:the discharge specific capacity at 0.1 C reaches 197.2 mA·h·g-1,capacity retention of discharge specific at 1 C reaches 93.1％and it still maitains 96.1％after 80 cycles compared to the first cycle,which is significantly higher than those of bare material.Additionally,the DSC exothermic peak temperature is delayed from 271.8 ℃ to 290.7 ℃,and the exothermic heat decreases from 459.8 J·g-1 to 306.5 J·g-1.Coating LATP with high ionic conductivity on the surface of the cathode material can improve the interfacial activity between the NCM and electrolyte,providing the fast lithium ion transport channel.The stable P-O bond in LATP may exert a pillar effect on surface oxygen and transition metals,preventing side reactions between NCM and electrolyte,and improving the stability of the NCM/electrolyte interface.
high-voltage LiNi0.6Co0.1Mn0.3O2Li1.3Al0.3Ti1.7(PO4)3 coatinginterfacial activityinterfacial stabilitylthium ion battery
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