Graphite-Based Composite Anodes with C−O−Nb Heterointerfaces Enable Fast Lithium Storage

To better satisfy the increasing demands for electric vehicles, it is crucial to develop fast-charging lithium-ion batteries (LIBs). However, the fast-charging capability of commercial graphite anodes is limited by the sluggish Li + insertion kinetics. Herein, we report a synergistic engineering of uniform nano-sized T-Nb 2 O 5 particles on graphite (Gr@Nb 2 O 5 ) with C−O−Nb heterointerfaces, which prevents the growth and aggregation of T-Nb 2 O 5 nanoparticles. Through detailed theoretical calculations and pair distribution function analysis, the stable existence of the heterointerfaces is proved, which can accelerate the electron/ion transport. These heterointerfaces endow Gr@Nb 2 O 5 anodes with high ionic conductivity and excellent structural stability. Consequently, Gr@10-Nb 2 O 5 anode, where the mass ratio of T-Nb 2 O 5 /graphite=10/100, exhibits excellent cyclic stability and incredible rate capabilities, with 100.5 mAh g −1 after 10000 stable cycles at an ultrahigh rate of 20 C. In addition, the synergistic Li + storage mechanism is revealed by systematic electrochemical characterizations and in situ X-ray diffraction. This work offers new insights to the reasonable design of fast-charging graphite-based anodes for the next generation of LIBs. Graphical Bond together : Benefiting from the C−O−Nb heterointerfaces that can effectively enhance the structure stability and facilitate electron/ion transport, composite of T-Nb 2 O 5 particles decorated on graphite exhibits low interfacial resistance, high Li + diffusion coefficient (nearly 34 times higher than graphite), and a high discharge capacity of 100.5 mAh g −1 after 10000 cycles at 20 C.