Combinatorial exploration of newly pseudo-quintenary layered-type Li-Ni-Co-Fe-Ti oxides

ABSTRACTIn order to decrease the use of cobalt element as in LiCoO2,which is mainly used for cathode materials in lithium ion secondary batteries, a newly pseudo-quintenary layered-type Fe-doped Li-Ni-Co-Ti oxides library was created using the combinatorial technology "M-ist Combi system" based on the electrostatic spray deposition method.The starting materials used were LiNO3, Ni(NO3)2·6H2O, Co(NO3)2·6H2O, Fe(NO3)3·9H2O and TiO2 nano-slurry. These materials were dissolved or dispersed in a mixture of ethanol and butyl carbitol and mixed in a predefined ratio, respectively. Subsequently, each of the mixtures was sprayed and dried on a grounded reaction plate that was heated to 400˚C. The deposited powder was sintered at 700˚C for 5 hours in air atmosphere. Phase identification of the obtained powder library was evaluated by a combinatorial powder x-ray diffractometer. A reaction phase diagram was established from the structure information and chemical composition by ICP-AES measurement.From all results, single-phase layered-type compounds showed the composition region that included many Co and Ni elements. On the other hand, single phase spinel-type compounds existed in the Ti-rich composition region.