title: Aligned TiO₂ nanotube/nanoparticle heterostructures with enhanced electrochemical performance as three-dimensional anode for lithium-ion microbatteries.
abstract: A novel TiO₂ three-dimensional (3D) anode with an aligned TiO₂ nanotube/nanoparticle heterostructure (TiO₂ NTs/NPs) is developed by simply immersing as-anodized TiO₂ NTs into water and further crystallizing the TiO₂ NTs by post-annealing. The heterostructure, with its core in a tubular morphology and with both the outer and inner surface consisting of nanoparticles, is confirmed by FESEM and TEM. A reversible areal capacity of 0.126 mAh · cm(-2) is retained after 50 cycles for the TiO₂ NTs/NPs heterostructure electrode, which is higher than that of the TiO₂ NTs electrode (0.102 mAh · cm(-2) after 50 cycles). At the current densities of 0.02, 0.04, 0.06, 0.08, 0.10 and 0.20 mA · cm(-2), the areal capacities are 0.142, 0.127, 0.117, 0.110, 0.104 and 0.089 mAh · cm(-2), respectively, for the TiO₂ NTs/NPs heterostructure electrode compared to the areal capacities of 0.123, 0.112, 0.105, 0.101, 0.094 and 0.083 mAh · cm(-2), respectively, for the the TiO₂ NTs electrode. The enhanced electrochemical performance is attributed to the unique microstructure of the TiO₂ NTs/NPs heterostructure electrode with the TiO₂ NT core used as a straight pathway for electronic transport and with TiO₂ NP offering enhanced surface areas for facile Li+ insertion/extraction. The results described here inspire a facile approach to fabricate a 3D anode with an enhanced electrochemical performance for lithium-ion microbattery applications.
authors.affiliation: State Key Laboratory of Solidification Processing and Center for Nano Energy Materials, Northwestern Polytechnical University, Xi'an, 710072, People's Republic of China.
authors.forename: Keyu
authors.initials: K
authors.lastname: Xie
authors.forename: Min
authors.initials: M
authors.lastname: Guo
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Haitao
authors.initials: H
authors.lastname: Huang
mesh_terms: D011211:Electric Power Supplies; D004563:Electrochemistry; D007477:Ions / Q000737:chemistry; D008094:Lithium / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D007477:Ions; C009495:titanium dioxide; D009532:Nickel; D008094:Lithium; D014025:Titanium