2D Nb2O5@2D Metallic RuO2 Heterostructures as Highly Reversible Anode Materials for Lithium-ion Batteries

Constructing two-dimensional (2D) heterostructured materials by stacking different 2D materials could combine the merits of the individual building blocks while getting rid of the associated shortcomings. Orthorhombic Nb2O5(T-Nb2O5) is one of the greatly promising candidates for durable and safety anode for Li-ion batteries (LIBs), but it usually exhibits poor electrochemical performance due to the low electronic conductivity. Herein, we realize excellent lithium storage performance of T-Nb2O5 by designing 2D Nb2O5@2D metallic RuO2 heterostructures (Nb2O5@RuO2). The presence of 2D metallic RuO2 leads to enhanced electronic conductivity. The 2D Nb2O5@RuO2 heterostructures possess very short diffusion length of ions/electrons, easy penetration of liquid electrolyte, and high conductivity transport of electrons through the 2D metallic RuO2 to 2D Nb2O5. The Nb2O5@RuO2 delivers remarkable rate performance (133 mAh g-1 and 106 mAh g-1 at 50 C and 100 C) and excellent long-life capacity (97 mAh g-1 after 10000 cycles at 50 C). Moreover, Nb2O5@RuO2//LiFePO4 full batteries also display high rate capability of 140 mAh g-1 and 90 mAh g-1 at 20 C and 50 C, respectively. Theoretical calculation results show that the 2D Nb2O5@RuO2 heterostructures possess more large adsorption ability for Li+ than that of Nb2O5 , indicating an excellent lithium storage performance.