Self-assembled mesoporous TiO2/carbon nanotube composite with a three-dimensional conducting nanonetwork as a high-rate anode material for lithium-ion battery

Abstract

Mesoporous three-dimensional (3D) TiO2/carbon nanotube conductive hybrid nanostructures can be successfully developed using polyethylene oxide (PEO) to modify the surfaces of carbon nanotubes (CNTs). During the synthesis process, PEO acts as not only “bridges” to connect the TiO2 nanoparticles to the CNT surfaces but also as “hosts” to accommodate and stabilize the in situ generated TiO2 particles. As the electrodes for lithium-ion batteries, such mesoporous 3D TiO2/CNT hybrids, demonstrate high Li storage capacity, superior rate performance and excellent long-term cycling stability. They exhibit a reversible specific capacity of 203 mA h g-1 at 100 mA g-1 and a stable capacity retention of 91 mA h g-1 at 8000 mA g-1 (47.6 C) over 100 cycles; they also retain approximately 90% (71 mA h g-1) of their initial discharge capacity after 900 cycles at an extremely high rate of 15,000 mA g-1 (89 C). This facile synthetic strategy to construct mesoporous 3D TiO2/CNT conductive hybrids provides a convenient route that efficiently assembles various inorganic oxide components on the CNTs' surfaces and enables the formation of heterogeneous nanostructures with novel functionalities. In particular, utilizing a conductive 3D CNT network can serve as a promising strategy for developing high-performance electrodes for Li secondary batteries and supercapacitors.