Multiscale Designed Niobium Titanium Oxide Anode for Fast Charging Lithium Ion Batteries

Abstract Fast charging of lithium ion batteries is essential for next‐generation energy‐storage systems. However, the poor ionic and electronic transport of anodes with its rather high mass loading limits the practical applications of this technology. Herein, a multiscale design from niobium titanium oxide anode material to electrode structure is proposed for fast charging lithium ion batteries with a practical level of areal capacity (3 mAh cm −2 ). At the atomic scale, the introduction of oxygen vacancy and surface carbon coating enables niobium titanium oxide (TiNb 2 O 7− x @C) to possess excellent ionic and electronic conductivity. For the microscopic electrode structure, 1D TiNb 2 O 7− x @C fibers are tightly assembled to form a high‐speed transport network of ions and electrons throughout the electrode. As a result, the obtained TiNb 2 O 7− x @C electrode shows excellent rate capability (1.83 mAh cm −2 at 1 C) and cycling stability under an areal capacity of 3 mAh cm −2 (2.35 mAh cm −2 after 100 cycles at 0.5 C) in half‐cells. Significantly, a full‐cell coupled with practical level mass loading of lithium cobalt oxide cathode is demonstrated to deliver 1.55 mAh cm −2 at 3 C for the first time.