Good cycling stability and high initial efficiency demonstrated in full cells with limited lithium source for an advanced SnO2–Co–C composite anode

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.