Al3+-doped FeNb11O29 anode materials with enhanced lithium-storage performance

FeNb 11 O 29 has a high theoretical capacity as a potential anode material for lithium-ion batteries; however, the practical capacity of FeNb 11 O 29 reported was unsatisfactory. In this study, a simple and efficient Al 3+ -doping technique was demonstrated to improve the electrochemical performance of FeNb 11 O 29 successfully. The influences of the Al 3+ doping amount were investigated. It was found that the crystal structure of FeNb 11 O 29 could be preserved when a suitable amount of Al 3+ was added, and that Al 0.2 Fe 0.8 Nb 11 O 29 demonstrated better electrochemical performance than FeNb 11 O 29 because the structure of Al 0.2 Fe 0.8 Nb 11 O 29 is more stable. At 0.1C, Al 0.2 Fe 0.8 Nb 11 O 29 possessed a high reversible capacity of 318 mAh g −1 with an initial-cycle Coulombic efficiency of 95.0%. Al 0.2 Fe 0.8 Nb 11 O 29 exhibited outstanding cycling stability with capacity retention of 92.9% at 10C over after 1000 cycles. Moreover, A LiFePO 4 /Al 0.2 Fe 0.8 Nb 11 O 29 full cell was prepared successfully with a discharge capacity of 206 mAh g −1 . The full cell exhibited good cycling stability showing the capacity retention of 84.2% over after 200 cycles at 1C and 89.8% over after 1000 cycles at 5C, respectively. This work suggests that Al 0.2 Fe 0.8 Nb 11 O 29 has great application prospects in lithium-ion batteries. Graphical abstract A suitable amount of Al 3+ doping in FeNb 11 O 29 significantly improves the electrochemical performance (especially the reversible capacity) of FeNb 11 O 29 .