Tao Liang,Renzong Hu,Houpo Zhang,Hanyin Zhang,Hui Wang,Yunpeng Ouyang,Jun Liu,Lichun Yang,Min Zhu
A new ternary SnO2–Co–C composite is produced using a facile and scalable ball milling method, which has a microstructure that includes refined SnO2–Co hybrids embedded in graphite. The Co additives dramatically inhibit Sn coarsening in the lithiated SnO2, which enables highly reversible conversion reactions in the SnO2-based ternary composite during cycling. The electrodes exhibit high ICEs with an average of 80.8% and a reversible capacity of 780 mA h g−1 at 0.2 A g−1 after 400 cycles when the composite was manufactured via small planetary ball milling, and they achieve 875 mA h g−1 after 250 cycles when the material is prepared on a large-scale with a roller mill. Even at a high rate of 2 A g−1, the composite has a long lifetime and delivers 610 mA h g−1 after 1000 cycles. Furthermore, a stable capacity of 410 mA h g−1 can be also retained in a full cell combined with a LiFePO4 cathode and SnO2–Co–C anode when cycling within 2.3–3.4 V at 0.2C. The new ternary SnO2–Co–C composite demonstrates excellent comprehensive electrochemical performances, and it is a promising candidate anode material for use in practical applications.
Gang Wen,Hui Liu,Tao Liang,Yunpeng Ouyang,Liang Tan,Renzong Hu,Jun Liu,Yao Zhang,Min Zhu
Despite there being many reports on SnO 2 -based anode materials, most of the electrode materials are tested in half cells using lithium metal with unlimited lithium-ion sources as the counter electrode, which may conceal the real properties of these composites to a certain extent. In this study, a ternary SnO 2 –Co–C composite was fabricated by a scalable ball milling strategy. The composite exhibited high initial Coulombic efficiency (ICE, >80%), a large capacity (∼900 mA h g −1 ) and superior cycling stability (capacity retention more than 99% after 100 cycles) in half cells. Furthermore, coin-type full cells in which the ternary SnO 2 –Co–C anodes were paired with different cathodes were demonstrated. A LiFePO 4 ||SnO 2 –Co–C full cell tested at 0.5–3.4 V exhibited an ICE of 75.1% and an initial discharge capacity of 906 mA h g −1 , which were close to those of the SnO 2 –Co–C||Li half cells. By analyzing the cycling performance and characteristics of the charge/discharge process for the full cells with different capacity ratios of cathode/anode, it was confirmed that the capacity decay of the full cells was due to the continuous consumption of Li + ions during cycling. Hence, the testing voltage windows were adjusted according to the lithiation/de-lithiation behavior of the SnO 2 . On this basis, the LiFePO 4 ||SnO 2 –Co–C full cells tested at 2.3–3.4 V and the LiCoO 2 ||SnO 2 –Co–C full cells tested at 2.60–3.75 V exhibited excellent cycling stability, demonstrating 80.3% and almost 100% capacity retention after 100 cycles, respectively, thereby laying a foundation for the practical application of advanced SnO 2 -based anodes in lithium-ion batteries.
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