Heteroepitaxial oxygen-buffering interface enables a highly stable cobalt-free Li-rich layered oxide cathode. (September 2020)

• Record Type: Journal Article
• Authors: Zhang, Chunxiao; Feng, Yuzhang; Wei, Bo; Liang, Chaoping; Zhou, Liangjun; Ivey, Douglas G.; Wang, Peng; Wei, Weifeng
• Is Part Of: Nano energy. Volume 75(2020)
• Publication Date: 2020-09
• Subjects: Cobalt-free Li-Rich layered oxides -- Fluorite ceria -- Rocksalt interphase -- Oxygen-buffering effects -- Cycle stability -- Voltage decay; 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.2020.104995
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: The oxygen redox process plays an essential role for the high charge-discharge capacity in Li-rich layered oxide (LLO) cathodes. The irreversible release of lattice oxygen may lead to surface reconstruction and cathode-electrolyte interfacial reactions, transition metal (TM) dissolution, as well as microcrack evolution, etc. during cycling that limit the commercial application of LLO cathodes. Herein, we propose the design of a heteroepitaxial Fluorite(CeO2 )@Rocksalt@Layered interface with oxygen buffering effects in Cobalt-free Li1.2 Mn0.53 Ni0.27 O2 through the incorporation of ceria. Experimental characterization and theoretical calculations reveal that the fluorite CeO2 nanolayer with oxygen vacancies suppresses the irreversible lattice oxygen loss and cathode-electrolyte interfacial reactions in LLOs. Moreover, the synergy involving the formed rocksalt interphase and Ce 3+ doping in the bulk not only stabilizes the structural integrity, resulting in substantial enhancement of capacity/voltage retention, but also accelerates the electrochemical kinetics upon cycling. This finding may pave the path for utilizing the reversible oxygen redox process and designing new high capacity TM-oxide cathode materials. Graphical abstract: Image 1 Highlights: Heteroepitaxial Fluorite(CeO2 )@Rocksalt@Layered interface with oxygen buffering effects is constructed in Li1.2 Mn0.53 Ni0.27 O2 . Oxygen vacancies in CeO2 and rocksalt interphase act as an oxygen buffer to suppress the irreversible release of oxygen. The CeO2 @Rocksalt interface prevents the direct exposure of the materials to the electrolyte, mitigating structural degradation. Ce 3+ doping can stabilize the structure and increase conductivity by tuning the electronic structure of the materials.