Vapor pressure-assisted synthesis of chemically bonded TiO₂/C nanocomposites with highly mesoporous structure for lithium-ion battery anode with high capacity, ultralong cycling lifetime, and superior rate capability

To date, development of a lithium-ion battery anode with high capacity, long cycling life over ten thousands of cycles, and fast lithium ion storage within a few seconds for each cycle is still a challenge. Here, a highly mesoporous TiO₂/C nanocomposite consisting of ultrathin carbon layers tightly coating on the surface of anatase TiO₂ nanocrystals with an average size of 20 nm via interfacial chemical bonds of Ti-O-C is obtained by a simple and facile vapor pressure-assisted synthesis route that pyrolysis of the solution of tetrabutyl orthotitanate tetramer dissolved in ethanol in a sealed vessel. As anode for lithium ion battery, the TiO₂/C nanocomposite shows a reversible capacity of 630.3 mAh g⁻¹ at 0.5C after 400 cycles, which is unprecedent for the ever reported TiO₂/C electrode at similar cycle number. Besides, the TiO₂/C nanocomposite also exhibits ultralong cycling lifetime (over 10000 cycles without capacity loss at 120C) and ultrahigh rate capability (20.5 mAh g⁻¹ at 144C). The outstanding lithium ion storage performances are ascribed to its unique structures, i.e., ultrathin carbon coating, ultrasmall TiO₂ particles, the formation of interfacial chemical bonds of Ti-O-C, and highly mesoporous structure.