Commercial lithium-ion batteries (LIBs) have potential safety issues due to the use of liquid electrolytes containing flammable organic solvents. In contrast, all-solid-state lithium batteries (ASSLB) can utilize inherently safe solid-state electrolytes. Thus, they are considered a secure, next-generation battery system, especially for electric vehicles and electric aircraft. Among many types of ASSLBs, all-solid-state lithium sulfur batteries (ASSLSBs) based on argyrodite electrolyte is considered as one of the most promising batteries because of their high ionic conductivity and mechanical properties. Significant efforts have been devoted toward developing argyrodite-type ASSLSBs, but the commercialization of these batteries still needs to resolve some scientific and technical problems, such as high ionic conductivity and stability, technology to reduce interfacial resistance between the electrolyte and electrode, technology to minimize reaction between the electrode and electrolyte materials, and scalability and large-scale manufacturing technology. One method to reduce interfacial resistance and minimize reaction between the electrolyte and cathode active materials such as lithium nickel manganese cobalt oxide (NMC) and lithium nickel cobalt aluminum oxide (NCA) is to coat them with a material which is compatible with argyrodite electrolyte. Several researchers have suggested lithium niobate (LiNbO3) (LNO) as an appropriate coating material. However, there is no systematic study on the effect of the coating material synthesis method and coating thickness on the performance of the NMC or NCA cathode active materials. The aims of this paper are to (a) compare two methods of synthesizing and coating of LNO on NMC active material, and (b) evaluate the coating thickness on the capacity, cycling, and rate performance of high-nickel NMC. For this purpose, LiNi0.85Mn0.1Co0.05O2 is chosen as the base cathode active material. This material has the particle size of approximately D50=4μm, D10=2μm, and D90= 6μm. The two synthesizing and coating methods that are studied are (1) mixing ammonium niobate oxalate hydrate (C4H4NNbO9) and lithium acetate dehydrate (CH3COOLi·2H2O) in deionized (DI) water, and (2) mixing lithium ethoxide (CH3CH2OLi) and niobium ethoxide (Nb(CH3CH2O)5) in dry ethanol. Both methods require thermal treatment. Several coating thickness from 0.5 nm to 50 nm are examined. To compare the coated NMCs, several LIB’ half-cells with liquid electrolyte are fabricated and tested. The results presented in this paper are the effect of coating thickness on (a) the active material specific capacity, (b) the cyclic and capacity retention of the active material, and (c) the rate performance of the active material. These results are presented for both synthesizing and coating methods of the NMC.

Effect of LiNbO3 Coating on Capacity and Cycling of Nickle-Rich NMC Cathode Active Material

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.