In Situ X-ray Diffraction and X-ray Absorption Spectroscopic Studies of a Lithium-Rich Layered Positive Electrode Material: Comparison of Composite and Core–Shell Structures

• DOI: 10.1021/acsami.9b21061
• Publication Date: 2020-03-13T14:43:46Z
• Authors: Cyril Osereme Ehi...; Sylvio Indris; Natalia N. Bramnik; Angelina Sarapulova; Vanessa Trouillet; Lukas Pfaffman; Georgian Melinte; Stefan Mangold; Mariyam Susana De...; Michael Knapp; Helmut Ehrenberg
• Keywords: Technology; ddc:600; 600; 02 engineering and technology; 540; 7. Clean energy; 543; FIB; TEM; info:eu-repo/classification/ddc/600; 2018-021-024249; 0210 nano-technology

Lithium- and manganese-rich transition-metal oxide (LMR-NMC) electrodes have been designed either as heterostructures of the primary components ("composite") or core-shell structures with improved electrochemistry reported for both configurations when compared their components. A detailed electrochemical structural investigation 0.5Li2MnO3-0.5LiNi0.5Mn0.3Co0.2O2 composite structured positive electrode materials is reported. The material shows better overall performance to its corresponding material. While gave same initial charge capacity ∼300 mAh/g cycled at a rate 10 mA/g 25 °C, sample gives discharge 232 208 delivered by sample. Also, capability smaller first-cycle irreversible loss than attributed lower surface reactivity limited change since more stable Li2MnO3 shell screens reactive Ni-rich core from interacting air electrolyte high potentials, thereby preventing modification. In situ X-ray diffraction correlated data revealed that stronger volumetric changes in lattice parameters during charging 4.8 V. addition, absorption spectroscopy showed an incomplete Ni reduction process after first From these results, it was shown this leads severe degradation affects Li+ intercalation subsequent discharge, resulting poorer performance. Furthermore, confirm another LMR-NMC different composition (having Ni-poor core)-0.5Li2MnO3-0.5LiNi0.33Mn0.33Co0.33O2-was investigated. also These results show configuration could effectively be used improve enable future high-energy applications.