FeNb11O29 nanotubes: Superior electrochemical energy storage performance and operating mechanism

Due to high capacity from multiple redox couples, niobium-based oxides are promising anode materials for lithium-ion batteries (LIBs). However, their poor electronic conductivity restricts their electrochemical performance. Here, we report the FeNb11O29 nanotubes as an advanced anode material. FeNb11O29 nanotubes exhibit an impressive charge capacity of 272.64 mAh g−1 with high initial cycle Coulombic efficiency of 90.13% at 0.1 C and outstanding cyclic stability (only 0.0123% of capacity decay per cycle during 2000 cycles). Furthermore, according to the in-situ XRD, the behavior of lithium atoms distribution in the FeNb11O29 framework during the insertion and extraction is studied in detail. In addition, full cells are assembled with commercially available cathodes. Coupled with LiFePO4, which is used as cathode, the full cell displays good electrochemical performance. In summary, FeNb11O29 nanotubes can be used as an ideal anode material due to the excellent electrochemical performance.