关键词: 硫掺杂, 二氧化钛, 二维过渡金属碳化物, 复合材料, 锂离子电池

Abstract:

Sulfur-doped titanium dioxide/titanium carbide(S-TiO₂/Ti₃C₂)composites were prepared via in-situ hydrothermal oxidation and chemical vapor phase sulfurization using two-dimensional layered Ti₃C₂ as the raw material. The results show that the TiO₂ nanoparticles in situ grew on the Ti₃C₂ nanosheets and sulphur was successfully doped into titanium dioxide. The S-TiO₂/Ti₃C₂ composite as anode material for lithium ion batteries exhibits superior electrochemical performance. A discharge specific capacity of 288 mA·h/g can be obtained after 100 cycles at a current density of 0.2 A/g, which is much higher than those of TiO₂/Ti₃C₂ and pure Ti₃C₂ electrodes. The outstanding cycle stability and discharge specific capacity of the S-TiO₂/Ti₃C₂ electrode are attributed to following reasons:TiO₂ nanoparticles electrically contacting Ti₃C₂ nanosheets can facilitate the interfacial electron transfer and effectively avoid the separation of the two components during the cycle. In addition, S-TiO₂ can improve the conductivity of the TiO₂ and produce some defects to enhance the reactivity. This work provides a new strategy for the preparation of two-dimensional composite materials through an in-situ transformation.

Key words: sulfur doping, titanium dioxide, two-dimensional transition metal carbides, composite, lithium-ion batteries