화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.159, No.6, A762-A769, 2012
Effect of 0.5 M NaNO3: 0.5 M KNO3 and 0.88 M LiNO3:0.12 M LiCl Molten Salts, and Heat Treatment on Electrochemical Properties of TiO2
The compounds, TiO2-1 & -2 were synthesized by 0.5 M NaNO3: 0.5 M KNO3 (I) and 0.88 M LiNO3:0.12 MLiCl (II) salts at 510 degrees C and 280 degrees C, resp.., XRD studies show single anatase phase with characteristic tetragonal lattice parameter values of a similar to 3.78 angstrom and c similar to 9.51 angstrom. The TEM images show aggregates of 10-30 nm sized nanosquares (TiO2-1) and spherical particles (TiO2-2). Surface area of the TiO2 powders were 74 and 200 m(2) g(-1), resp. for 1 and 2. Upon heat-treatment (TiO2-2) from 500 degrees C to 850 degrees C, the surface area decreases from 80 to 0.7 m(2) g(-1). Cyclic voltammetry studies show cathodic and anodic peaks at similar to 1.7 and similar to 2.0 V, resp. for both bare and heat treated TiO2 up to 750 degrees C. Galvanostatic cycling studies show that the first discharge-charge capacity values are 244 and 198 (+/- 3) mAh g(-1) resp. for TiO2-1 at a current of 33 mA g(-1) in the voltage window, 1.0-2.8 V vs. Li/Li+. TiO2-2 nanoparticles show a less capacity fade during cycling and delivered first discharge-charge capacity values of 340 and 253 (+/- 3) mAh g(-1), resp. at a current rate of 33 mA g(-1). The effects of heat-treatment and Li-cycling at a cutoff voltage (0.005 V) were studied and discussed reaction mechanism. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.077206jes] All rights reserved.