Accurate Control of Initial Coulombic Efficiency for Lithium-rich Manganese-based Layered Oxides by Surface Multicomponent Integration

Dong Luo; Xiaokai Ding; Jianming Fan; Zuhao Zhang; Peizhi Liu; Xiaohua Yang; Junjie Guo; Shuhui Sun; Zhan Lin

doi:10.1002/anie.202010531

Accurate Control of Initial Coulombic Efficiency for Lithium-rich Manganese-based Layered Oxides by Surface Multicomponent Integration

Angew Chem Int Ed Engl. 2020 Dec 14;59(51):23061-23066. doi: 10.1002/anie.202010531. Epub 2020 Oct 15.

Authors

Dong Luo¹, Xiaokai Ding¹, Jianming Fan², Zuhao Zhang¹, Peizhi Liu³, Xiaohua Yang⁴, Junjie Guo³, Shuhui Sun⁴, Zhan Lin¹

Affiliations

¹ Guangzhou Key Laboratory of Clean Transportation Energy Chemistry, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, China.
² Fujian Provincial Key Laboratory of Clean Energy Materials, College of Chemistry and Materials, Longyan University, Longyan, 364012, China.
³ Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China.
⁴ Institut National de la Recherche Scientifique-Center for Energy, Materials and Telecommunications, Varennes, Quebec, J3X 1S2, Canada.

PMID: 32820858
DOI: 10.1002/anie.202010531

Abstract

Low initial Coulombic efficiency (ICE) is an obstacle for practical application of Li-rich Mn-based layered oxides (LLOs), which is closely related with the irreversible oxygen evolution owing to the overoxidized reaction of surface labile oxygen. Here we report a NH₄ F-assisted surface multicomponent integration technology to accurately control the ICE, by which oxygen vacancies, spinel-layered coherent structure, and F-doping are skillfully integrated on the surface of treated LLOs microspheres. Though the regulation on the removed amount of labile oxygen by surface integrated structure, the ICE of LLOs cathodes can adjust from starting value to 100 %. X-ray absorption spectroscopy, refined X-ray diffraction, and scanning transmission electron microscopy show that the removed labile oxygen mainly comes from Li₂ MnO₃ -like structure. Even operating at a high cut-off voltage of 5 V, the capacity retention of integrated sample at 200 mA g^-1 is still larger than 98 % after 100 cycles.

Keywords: Li-rich Mn-based layered oxides; cathodes; initial Coulombic efficiency; lithium-ion batteries; surface modification.