Hierarchical engineering, heterogeneous engineering, and defect engineering enabled high-performanced NbO2.5-x@C anode material for lithium-ion batteries

The design and synthesis of high-performanced anode materials is the key to further improve the performance of lithium-ion batteries (LIBs). In this work, in-situ carbon-coated NbO 2.5-x @C anode materials are prepared to realize synergy of hierarchical engineering, heterogeneous engineering, and defect engineering. The NbO 2.5-x @C anode material delivers a high initial discharge specific capacity of 372 mAh/g and a good cycling stability. In addition, in-situ X-ray diffraction (XRD) and ex-situ X-ray photoelectron spectroscopy (XPS) measurements reveal the mechanism of transformation reaction and (de)intercalation reaction during the charging-discharging processes. This study provides an effective strategy for the design and synthesis of high-performance oxide anode materials for LIBs.