title: Combinatorial Study of the Li-Ni-Mn-Co Oxide Pseudoquaternary System for Use in Li-Ion Battery Materials Research.
abstract: Combinatorial synthesis has proven extremely effective in screening for new battery materials for Li-ion battery electrodes. Here, a study in the Li-Ni-Mn-Co-O system is presented, wherein samples with nearly 800 distinct compositions were prepared using a combinatorial and high-throughput method to screen for single-phase materials of high interest as next generation positive electrode materials. X-ray diffraction is used to determine the crystal structure of each sample. The Gibbs' pyramid representing the pseudoquaternary system was studied by making samples within three distinct pseudoternary planes defined at fractional cobalt metal contents of 10%, 20%, and 30% within the Li-Ni-Mn-Co-O system. Two large single-phase regions were observed in the system: the layered region (ordered rocksalt) and cubic spinel region; both of which are of interest for next-generation positive electrodes in lithium-ion batteries. These regions were each found to stretch over a wide range of compositions within the Li-Ni-Mn-Co-O pseudoquaternary system and had complex coexistence regions existing between them. The sample cooling rate was found to have a significant effect on the position of the phase boundaries of the single-phase regions. The results of this work are intended to guide further research by narrowing the composition ranges worthy of study and to illustrate the broad range of applications where solution-based combinatorial synthesis can have significant impact.
authors.affiliation: †Department of Physics and ∥Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
authors.forename: Colby R
authors.initials: CR
authors.lastname: Brown
authors.affiliation: †Department of Physics and ∥Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: McCalla
authors.affiliation: †Department of Physics and ∥Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
authors.forename: Cody
authors.initials: C
authors.lastname: Watson
authors.affiliation: †Department of Physics and ∥Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
authors.forename: J R
authors.initials: JR
authors.lastname: Dahn
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D011211:Electric Power Supplies; D008094:Lithium / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D010087:Oxides; C491691:lithium cobalt oxide; C488552:lithium manganese oxide; D003035:Cobalt; D008345:Manganese; D009532:Nickel; D008094:Lithium; C028007:nickel monoxide
keywords: Li−ion cathode; X-ray diffraction; combinatorial synthesis; cubic spinel; layered lithium transition metal oxides; single-phase materials