Surface Modification of the LiNi_0.5Co_0.2Mn_0.3O₂ Cathode by a Protective Interface Layer of Li_1.3Ti_1.7Al_0.3(PO₄)₃

Solid-state batteries are the next step on the way of developing lithium power sources because of combination of high energy density (up to 500 W/kg and 1000 W/l) and better safety. Yet their major drawbacks are high interfacial resistance and poor interface contacts between the solid electrolyte and active material. One of possible solutions to the problem is to produce an active material whose particles would be coated with a solid electrolyte. Titanium-aluminum-lithium phosphate Li 1,3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) is a solid electrolyte which exhibits one of the highest conductivity (∼10 −3 −10 −5 S/cm) and is chemically stable. Therefore, the aim of this study was synthesis and investigation of composite cathodes based on cathode materials LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NMC) with protective interface layer of solid state electrolyte LATP. The influence of the amount of LATP on the electrochemical properties of NMC was investigated. The composite NMC cathode material with protective interface layer of solid state electrolyte with content of LATP 1% exhibited high capacity (ca. 150 mAh g −1 ) and good cycle performance with a high charge cutoff voltage up to 4.5 V.