Preparation And Electrochemical Performance Of Heteroatom-doped TiO₂ Nanocomposite Materialo For Lithium Batteries

Titania?TiO₂?,as a semiconductor material,has become an appealing anode alternative in Li-ion batteries due to its good chemical stability,non-toxicity,extreme safety,and low cost.However,its low electronic conductivity and poor ionic diffusion ability have limited its practical application.In this paper,we improved the electrochemical performance of TiO₂ material by compositing with highly conductive materials,heteroatoms doping and reducing particle size of TiO₂.Free-standing films of N-doped C/ TiO₂ nanofibers have been successfully prepared via electrospinning and followed heat-treatment using titanium tetraisopropoxide as titanium source and polyvinyl pyrrolidone as carbon source and nitrogen source.The as-prepared film was tested as an anode in lithium-ion batteries.The heating temperature and the presence of carbon in the composites are found to affect TiO₂ phase transformation and grain growth region in the nanofibers.The hierarchical TiO₂ nanofibers whose “trunk” were mainly composed of small anatase grains and the outer “leaves” composed of rutile have been obtained with the increase of heating treatment temperature.Electrochemical results demonstrated that the film prepared at 800 °C showed a high specific capacity and superior rate performance?180 mA h/g at 5 A/g?as well as excellent cycle stability?the capacity can retain 93% within 100 cycles at the current density of 0.1 A/g?Carbon doped TiO₂/TiC nanocomposites were prepared via hydrothermal-assisted heat-treatment method using incompletely oxidized TiC as precursor and studied its electrochemical performance as anode material in Li-ion battery.The electrochemical performance test results demonstrated that as-prepared nanocomposites heat-treated at 400 °C exhibit superior rate performance?142 mA h/g at 15 A/g?as well as excellent cycle stability ability?the capacity can retain 94% within 200 cycles at the current density of 2 A/g?.