Synthesis of full concentration gradient cathode studied by high energy X-ray diffraction. (January 2016)

• Record Type: Journal Article
• Authors: Li, Yan; Xu, Rui; Ren, Yang; Lu, Jun; Wu, Huiming; Wang, Lifen; Miller, Dean J.; Sun, Yang-Kook; Amine, Khalil; Chen, Zonghai
• Is Part Of: Nano energy. Volume 19(2016:Jan.)
• Page Start: 522
• Page End: 531
• Publication Date: 2016-01
• Subjects: In situ XRD -- Full concentration gradient cathode -- Lithium ion battery; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2015.07.019
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Nickel-rich metal oxides have been widely pursued as promising cathode materials for high energy-density lithium-ion batteries. Nickel-rich lithium transition metal oxides can deliver a high specific capacity during cycling, but can react with non-aqueous electrolytes. In this work, we have employed a full concentration gradient (FCG) design to provide a nickel-rich core to deliver high capacity and a manganese-rich outer layer to provide enhanced stability and cycle life. In situ high-energy X-ray diffraction was utilized to study the structural evolution of oxides during the solid-state synthesis of FCG lithium transition metal oxide with a nominal composition of LiNi0.6 Mn0.2 Co0.2 O2 . We found that both the pre-heating step and the sintering temperature were critical in controlling phase separation of the transition metal oxides and minimizing the content of Li2 CO3 and NiO, both of which deteriorate the electrochemical performance of the final material. The insights revealed in this work can also be utilized for the design of other nickel-rich high energy-density cathode materials. Graphical abstract: Benefit from the covariance analysis and Rietveld refinement of in situ HEXRD data during the solid state synthesis, we can optimized the solid state synthesis conditions in a short time. And the full concentration gradient cathode composites (nickel-rich core and manganese-rich outer layer) with excellent electrochemical performance are obtained. Highlights: Solid-state synthesis of FCG cathode is investigated by in situ XRD. Covariance analysis and Rietveld refinement are used to analyze the HEXRD data. Synthetic optimization of FCG cathode with excellent electrochemical performance.