title: Multi-yolk-shell SnO2/Co3Sn2@C Nanocubes with High Initial Coulombic Efficiency and Oxygen Reutilization for Lithium Storage.
abstract: The challenging problems of SnO2anode material for lithium ion batteries are the poor electronic conductivity and the low oxygen reutilization due to the irreversibility of Li2O generated in the initial discharge leading to a theoretical initial Coulombic efficiency (ICE) of only 52.4%. Different from these strategies, this work proposes a novel strategy to level up the oxygen reutilization in SnO2by introducing Co3Sn2nanoalloys which can release Co atoms to reversibly react with Li2O instead. According to this protocol, multi-yolk-shell SnO2/Co3Sn2@C nanocubes are designed and successfully prepared using hollow CoSn(OH)6nanocubes as precursors followed a hydrothermal carbon coating and calcination treatment. The unique multi-yolk-shell nanostructure offers adequate breathing space for the volumetric deformation during long-term cycling. Moreover, the removal of Li2O allows a high electronic conductivity and resultant rate performance. As a result, the efficient reutilization of oxygen enables a high ICE of 71.7% and a reversible capacity of 1003 mA h g-1after 200 cycles at 100 mA g-1. Cyclic voltammetry, cycling performance at different voltage windows, and X-ray photoelectron spectroscopy confirm the proposed mechanism. This strategy employing oxygen-poor metals or alloys provides a novel approach to enhance the oxygen reutilization in SnO2for higher reversibility.
authors.affiliation: State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China.
authors.forename: Liwei
authors.identifier: http://orcid.org/0000-0002-9791-3476
authors.initials: L
authors.lastname: Su
authors.affiliation: State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China.
authors.forename: Yawei
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xie
authors.affiliation: State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China.
authors.forename: Lianbang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Faculty of Science and Technology, Technological and Higher Education Institute of Hong Kong , Hong Kong 999077, China.
authors.forename: Yuanhao
authors.initials: Y
authors.lastname: Wang
keywords: Coulombic efficiency; lithium ion batteries; multi-yolk−shell structures; oxygen reutilization; reversible conversion