ORALS

SESSION: BatteryMonPM2-R9	5th Intl. Symp. on Sustainable Secondary Battery Manufacturing and Recycling
Mon Nov, 5 2018 / Room: Asian (60/3rd)
Session Chairs: Thierry Djenizian; Vimalnath Selvaraj; Session Monitor: TBA

16:45: [BatteryMonPM211]
High Performance of Chemically Modified TiO₂ Nanotubes for Lithium-ion Microbatteries
Thierry Djenizian¹ ; ¹Ecole des Mines Saint-Etienne, Gardanne, France;
Paper Id: 203 [Abstract]

Modern microelectronic devices such as backup power for computer memories, MicroElectroMechanical Systems (MEMS), medical implants, smart cards, Radio-Frequency Identification (RFID) tags, and remote sensors have necessitated the development of high performance power sources at the microscale. In this context, the development of three-dimensional (3D) microbatteries forms a viable alternative to provide high volumetric energy densities to meet the demands of these devices.[1] The development of nano-architectured electrodes is one of the most promising approaches to realize the 3D paradigm of microbatteries.[2] Among all the potential anode materials, TiO₂ nanotubes (TiO₂-NTs) possess remarkable characteristics for the design of 3D Li-ion microbatteries. Self-organized nanotubular materials allow a good diffusion of Li ions in the porous structures, and the 1D morphology allows an efficient charge transfer along the axis of the tube that results in a good apparent electronic conductivity of the TiO₂-NTs layer, when compared to a film composed of nanoparticles [3,4]. Anatase TiO₂ can accommodate only 0.5 Li⁺ per formula unit, corresponding to a theoretical capacity of 168 mAh g^-1. Hence, several approaches have been investigated to improve the overall performance of TiO₂-NTs for the design of high-performance Li-ion microbatteries. Doping with aliovalent ions like Niobium (Nb⁵⁺) is also a facile strategy to modify the electronic properties of titanium oxide and thereby enhance the electrochemical performance.[5,6] <br />We report the fabrication of self-supported Nb doped TiO₂-NTs by anodization of Nb/Ti alloys devoid of any carbon additives or binders. An increase in the capacity of the TiO₂-NTs was observed as the Nb doping concentration increased. Such a composition of 10 wt.% Nb doped TiO₂-NTs (Nb10-TiO₂-NTs) showed a first cycle capacity of 200 mAh.g^-1 (0.144 mAh.cm^-2) compared to pristine TiO₂-NTs, which gave a capacity of 115 mAh.g^-1 (0.078 mAh.cm^-2) at C/10. Galvanostatic cycling tests at various C-rates revealed the influence of Nb doping in the TiO₂-NTs. Compared to pristine TiO₂-NTs, the discharge capacities of doped nanotubes are improved and almost doubled when the Nb concentration reaches 10 wt.%. Besides a good cycling behaviour at multiple C-rates, an overall capacity retention of 87 % is achieved after 100 cycles. According to Electrochemical Impedance Spectroscopy measurements, the enhanced electrochemical performance of the Nb-doped TiO₂-NTs is attributed to their higher electronic conductivity.

References:
[1] B.L. Ellis, P. Knauth, T. Djenizian, Three-Dimensional self-supported metal oxides for advanced energy storage, Adv. Mater. 26 (2014) 3368-3397.\n[2] J.W. Long, B. Dunn, D.R. Rolison, H.S. White, Three-Dimensional Battery Architectures, Chem. Rev., 104 (2004), 4463-4492.\n[3] G.F. Ortiz, I. Hanzu, T. Djenizian, P. Lavela, J.L. Tirado, P. Knauth, Alternative Li-Ion Battery Electrode Based on Self-Organized Titania Nanotubes, Chem. Mater., 21 (2009), 63-67.\n[4] T. Djenizian, I. Hanzu, P. Knauth, Nanostructured negative electrodes based on titania for Li-ion microbatteries , J. Mater. Chem., 21 (2011), 9925-9937.\n[5] Y.Wang, B. M Smarsly, I. Djerdj, Niobium Doped TiO2 with Mesoporosity and Its Application for Lithium Insertion, Chem. Mater., 22 (2010), 6624-6631.\n[6] M. Fehse, S. Cavaliere, P. E. Lippens, I. Savych, A. Iadecola, L. Monconduit, D. J. Jones, J. Roziere, F. Fischer, C. Tessierand, L. Stievano, Nb-Doped TiO2 Nanofibers for Lithium Ion Batteries, J. Phys. Chem. C, 117 (2013), 13827-13835.