Phosphorus-doped urchin-like Nb2O5 microspheres as stabilised anodes for lithium-ion batteries with excellent rate performance

It is crucial to explore new anode materials with outstanding electrochemical properties for the development of lithium-ion batteries (LIBs). Nb₂O₅ is considered a promising anode material for LIBs owing to its rich redox chemistry (Nb⁵⁺∼ Nb³⁺), excellent rate performance and durability over long-term cycling. Nevertheless, its practical application is restricted by its low electrical conductivity. In this study, phosphorus-doped Nb₂O₅ (P-Nb₂O₅) with an urchin-like structure was prepared through hydrothermal method and subsequent low-temperature phosphorization, utilizing sodium hypophosphite monohydrate as the phosphorus source. Such urchin-like P-Nb₂O₅ exhibits outstanding high-rate capacity up to 137 mAh g^-1 at 20 C, and exceptional cycling stability of 147 mAh g^-1 at 10 C after 500 cycles. Furthermore, the excellent electrochemical performance is also verified in LiNi_0.5Mn_0.3Co_0.2O₂//P-Nb₂O₅ full cell, such as good rate capability (89 mAh g^-1 at 10 C), and superior cyclability (capacity retention of 93.9 % at 5 C after 1000 cycles). The superior performance of the P-Nb₂O₅ anode can be ascribed to its urchin-like structure and P-doping modification, which helps to inspire more thoughts on the synergistic design of Nb₂O₅ molecules and structure engineering.