Outstanding rate capability and long cycle stability induced by homogeneous distribution of nitrogen doped carbon and titanium nitride on the surface and in the bulk of spinel lithium titanate

Highlights: • N-doped carbon and TiN distribution throughout the whole particle of LTO is prepared. • Carbon and N enter the bulk of LTO through the interlayer galleries of precursor. • Carbon promotes the formation of TiN and resulting in improved conductivity. • The samples exhibit markedly improved electrochemical properties. - Abstract: N-doped carbon and TiN composite conductive structure with homogeneous distribution on the surface and in the bulk of spinel lithium titanate (Li4Ti5O12) nanoparticles is prepared via a simple one-step chemical vapor deposition assisted solid-state route in the presence of layered structure sodium titanate nanotubes as the titanium source and ethylenediamine as the carbon and nitrogen source. Results indicate that as-fabricated Li4Ti5O12 samples containing N-doped carbon and TiN composite conductive structure exhibit markedly improved electrochemical properties as compared with pristine Li4Ti5O12. Particularly, the electrode made from Li4Ti5O12 containing N-doped carbon and TiN composite conductive structure obtained after 60 min of treatment in the presence of ethylenediamine has a high capacity of 162 mAh·g−1 at a charge/discharge rate of 20C as well as a substantial capacity of 92% and a capacity retention of 75% after 2500 cycles at 10C, showing superior electrochemical performance and great potential as an anode material for high-rate lithium-ion batteries. The enhanced electrochemical performance of the composite electrodes can be attributed to the small size of Li4Ti5O12 nanoparticles as well as the uniform distribution of N-doped carbon and TiN composite conductive structure on the surface and in the bulk of Li4Ti5O12 nanoparticles