High Lithium Insertion Voltage Single‐Crystal H 2 Ti 12 O 25 Nanorods as a High‐Capacity and High‐Rate Lithium‐Ion Battery Anode Material

H 2 Ti 12 O 25 holds great promise as a high‐voltage anode material for advanced lithium‐ion battery applications. To enhance its electrochemical performance, control of the crystal orientation and morphology is an effective way to cope with slow Li + ‐ion diffusion inside H 2 Ti 12 O 25 with severe anisotropy. In this report, Na 2 Ti 6 O 13 nanorods, prepared from Na 2 CO 3 and anatase TiO 2 in molten NaCl medium, were used as a precursor in the synthesis of long single‐crystal H 2 Ti 12 O 25 nanorods with reactive facets. The as‐prepared H 2 Ti 12 O 25 nanorods with a diameter of 100–200 nm showed higher charge (extraction) specific capacity and better rate performance than previously reported systems. The reversible capacity of H 2 Ti 12 O 25 was 219.8 mAh g −1 at 1C after 100 cycles, 172.1 mAh g −1 at 10C, and 144.4 mAh g −1 at 20C after 200 cycles; these values are higher than those of H 2 Ti 12 O 25 prepared by the conventional soft‐chemical method. Moreover, the as‐prepared H 2 Ti 12 O 25 nanorods exhibited superior cycle stability with more than 94 % retention of capacity with nearly 100 % coulombic efficiency after 100 cycles at 1C. On the basis of the above results, long single‐crystal H 2 Ti 12 O 25 nanorods synthesized in molten NaCl with outstanding electrochemical characteristics hold a significant amount of promise for hybrid electric vehicles and energy‐storage systems.