On the basis of the advantages of ideal cycling stability, high discharge voltage (1.65 V), and excellent reversibility, more and more attention has been focused on TiNbO (marked as TNO) as an anode material candidate for lithium-ion batteries. However, the poor electronic conductivity and low ionic diffusion rate intrinsically restrict its practical use. Herein, we first synthesize the TNO/C composite microspheres with three-dimensionally (marked as 3D) electro-conductive carbon network and abundant nanoporous structure by a simple spray-drying method. The microspheres are constructed by irregularly primary cubic nanoparticle units with size of 100-200 nm. The nanopores throughout the microspheres range from 1 to 50 nm. As an anode material, the prepared TNO/C composite microspheres demonstrate a prominent charge/discharge capacity of 323.2/326 mA h g after 300 cycles at 0.25 C (1 C = 388 mA g) and 259.9/262.5 mA h g after 1000 long cycles at a high current density of 5 C, revealing the ideal reversible capacity and long cycling life. Meanwhile, the TNO/C composite microspheres present ideal rate performance, showing the discharge capacity of 120 mA h g at 30 C after 10 cycles. The super electrochemical performance could be attributed to the 3D electro-conductive carbon network and nanoporous structure. The nanopores facilitate the permeation of electrolyte into the intercontacting regions of the anode materials. Carbon layers disperse uniformly throughout the 3D microspheres, effectively improving the electrical conductivity of the electrode. Hence, the prepared TNO/C composite microspheres have great potential to be used as an anode material for lithium-ion batteries.

TiNb O , with high charge/discharge voltage (1.65 V), long life span, and excellent reversibility has become a new anode material for lithium ion batteries in recent years. However, the inherent poor electronic conductivity strictly limits its practical applications. Herein, we report for the first time hollow TiNb O @C spheres, with carbon spheres as sacrificial template. The special hollow structure can effectively relieve the volume expansion during the repeated process of charging/discharging. The conductivity of hollow TiNb O spheres can be greatly improved by the carbon layers uniformly coated outside the surface of TiNb O spheres. Besides, the particle aggregation can be conspicuously suppressed by the uniformly coated carbon layers. As a result, hollow TiNb O @C spheres show a prominent charge/discharge capacity of 282.6/283.8 mAh g after 100 cycles at 0.25 C (1 C=388 mA g ), revealing the excellent cycle performance and high reversible capacity. Meanwhile, the charge/discharge capacity of 157.5 and 157.9 mAh g can be maintained at 10 C after 10 cycles. The facial synthetic method can be extended to prepare various materials with volume expansion during repeated charging/discharging process.

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