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 O particles on graphite (Gr@Nb O ) with C-O-Nb heterointerfaces, which prevents the growth and aggregation of T-Nb O 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 O anodes with high ionic conductivity and excellent structural stability. Consequently, Gr@10-Nb O anode, where the mass ratio of T-Nb O /graphite=10/100, exhibits excellent cyclic stability and incredible rate capabilities, with 100.5 mAh g 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.