科研之友
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摘要
Despite there being many reports on SnO2-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 SnO2-Co-C composite was fabricated by a scalable ball milling strategy. The composite exhibited high initial Coulombic efficiency (ICE, > 80%), a large capacity (similar to 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 SnO2 -Co-C anodes were paired with different cathodes were demonstrated. A LiFePO4 vertical bar vertical bar SnO2-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 SnO2-Co-CIILi 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 SnO2. On this basis, the LiFePO4 vertical bar vertical bar SnO2-Co-C full cells tested at 2.3-3.4 V and the LiCoO2 vertical bar vertical bar SnO2-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 SnO2-based anodes in lithium-ion batteries.
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单位湖南农业大学
