High lithium ion conductivity solid electrolyte of chromium and aluminum co-doped NASICON-type LiTi2(PO4)3 (original) (raw)
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Solid State Ionics, 2013
Solid ionic conductors composed of Li 1.4 Al 0.4 Ti 1.6 − x Ge x (PO 4) 3 (x = 0-1.0) with the NASICON-type structure were synthesized with a precursor prepared using the sol-gel method. The electrical conductivity was examined as a function of x in Li 1.4 Al 0.4 Ti 1.6 − x Ge x (PO 4) 3 at various sintering temperatures and for various sintering periods. The highest electrical conductivity was obtained for Li 1.4 Al 0.4 Ti 1.4 Ge 0.2 (PO 4) 3 sintered at 900°C for 11 h in air. The total and bulk conductivities of the sintered pellet were 1.29 × 10 −3 and 2.35 × 10 −3 S cm − 1 at 25°C, respectively. The grain boundary resistance of Li 1.4 Al 0.4 Ti 1.4 Ge 0.2 (PO 4) 3 was significantly increased to 552 Ω cm 2 from 12.2 Ω cm 2 by immersion in distilled water at 50°C for one week, whereas the bulk resistance was not increased. However, no significant increase of the bulk and grain boundary resistance was observed after immersion in a saturated aqueous solution of LiOH and LiCl.
International Journal of Integrated Engineering
Despite the attractive features of NASICON LATP, it is not clear whether the high conductivity of Li 1+x Ti 2−x Al x (PO 4) 3 composition is intrinsic to the structure or the formation of secondary phases that favors sintering and eliminate grain-boundary resistance is the cause of high conductivity [5], [6]. Towards this end, lithium-ion conduction of mixed-metal NASICON-phases of the formula, LiM v M iii (PO 4) 3 , where M V = Nb, Ta; M iii = Al, Cr, Fe were examined to obtained a NASICON phase possessing intrinsic conducting properties similar to LiTi 2 (PO 4) 3 but without Ti iv [6]. The planetary mono mill is a technique that uses a high energy ball mill for synthesizing solid electrolyte materials to achieve phase homogeneity of the final product. However, the use of this milling machine is a well-known technique and has attracted the interest of
High Lithium Ionic Conductivity in the Li1+xAlxGeyTi2-x-y(PO4)3 NASICON Series
Chemistry of Materials, 2003
Two Li 1+x Al x Ge y Ti 2-x-y (PO 4) 3 (0.2 e x e 0.8; y) 0.8, 1.0) solid solutions have been prepared as polycrystalline powders. These compounds crystallize in the NASICON-type structure, R3 hc space group, and the crystal structures have been characterized by the Rietveld method with laboratory X-ray powder diffraction data. The cell parameters evolution along the two series agrees with the substitution of larger Ti 4+ by smaller Ge 4+ and Al 3+ cations. The electrical properties have been characterized by an impedance study. Bulk conductivity values at room temperature are close to 10-3 S‚cm-1 with low activation energies (≈0.35 eV). The trajectories of the Li + cations have been simulated from the bond valence sum calculation. Structural keys, which justify the high ionic conductivity and the low activation energy, are discussed.
The electrical and thermal properties of LiTi2( PO 4 I~ (LTP) and LTP composite electrolytes were investigated. LTP-LiNO~ composite electrolyte sintered at 900 °C revealed high conductivity (approximately 10 5 S cm ~ at 25 °C), compared with pure LTP sintered at the same temperature. The thermal behavior in the smtermg process of pure LTP and LTP composite electrolytes was examined. Consequently. we found that the conductivity of the composite electrolyte was enhanced by partial melting and subsequent solidification of the pellet at around 800 °C. This phenomenon was attributed to the coexistence of Li4PeO 7 which was a byproduct of the decomposition of LiNO~ and LTP. © 1997 Published by Elsevier Science S.A.
LiSnZr(PO4)3: NASICON-type solid electrolyte with excellent room temperature Li+ conductivity
Journal of Alloys and Compounds, 2018
Development of solid electrolytes with good lithium ion conductivity is one of the key prerequisites of high performing rechargeable all-solid-state lithium batteries. In this work, NA-Super-Ionic-CONductor (NASICON)-type LiSnZr(PO 4) 3 ceramics fabricated via a sol-gel route were characterized using Synchrotron x-ray diffraction, Raman Spectroscopy, x-ray photoelectron spectroscopy (XPS) and complex impedance spectroscopy. Stabilization of high Li + conducting rhombohedral (R3 c) phase at room temperature was confirmed by the Rietveld refinement of synchrotron x-ray diffraction data. LiSnZr(PO 4) 3 sample sintered at 1000 °C exhibited an excellent room temperature bulk and total conductivity ~ 0.1 mScm-1 and 1.45×10-5 Scm-1 with associated activation energies of ~ 0.36 eV and ~ 0.38 eV, respectively. Direct current polarization study confirmed the conductivity of LiSnZr(PO 4) 3 as predominantly ionic in nature. The role of inductive effect in improving the room temperature ionic conductivity by utilizing the electronegativity of counter-cations in NASICON framework is also discussed.
NASICON-type La3+substituted LiZr2(PO4)3 with improved ionic conductivity as solid electrolyte
Electrochimica Acta, 2018
NASICON-structured Li 1+x Zr 2-x La x (PO 4) 3 (x = 0-0.2) solid electrolytes are prepared by sol-gel method. The influence of substitution of La 3+ for Zr 4+ on the ionic conductivity, morphology, and structure of the parent compound LiZr 2 (PO 4) 3 (LZP) is investigated. Rietveld refinement of powder x-ray diffraction data reveals that the La 3+ substitution stabilizes the LZP in the highly conducting rhombohedral R3 c phase at room temperature. La 3+ substituted LZP display enhanced ionic conductivity, showing the highest ionic conductivity of 0.72 x 10-4 S/cm at room temperature for the composition Li 1.1 Zr 1.9 La 0.1 (PO 4) 3. The improvement in conductivity of LZP with another aliovalent substituent, Mg 2+ , whose ionic radii is similar to Zr 4+ (0.72 Ǻ) is also investigated. Further, the activation energy decreases from 0.53 eV for the parent LZP to 0.42 eV for x = 0.1 La 3+ substituted LZP. Lithium-ion transference number obtained by direct current polarization for Li 1.1 Zr 1.9 La 0.1 (PO 4) 3 is 0.99, confirming the high ionic conducting nature of the solid electrolyte. Cyclic voltammetry recorded for Li 1.1 Zr 1.9 La 0.1 (PO 4) 3 shows electrochemical stability window up to ~4.0 V vs. Li. In particular, La 3+ substituted NASICONtype LZP (x=0.1) exhibits good chemical and structural stability after exposing to air, water, Li metal, acidic and basic solutions.
Conductivity studies and ion transport mechanism in LiILi 3 PO 4 solid electrolyte
Ionics, 2009
Mixtures of LiI-Li 3 PO 4 were sintered at low temperature. It was observed that the conductivity improved up to 10 −3 S cm −1 with the addition of LiI. Infrared technique (Fourier transform infrared spectroscopy [FTIR]) was employed to detect the presence of polyhedral structures. From the FTIR spectra of the binary samples with various weight percents of LiI, the PO 4 3− bands and the PO bending experienced small shifting which indicates that interaction has occurred. Alternating current conductivity versus frequency shows a linear variation suggesting that the behavior follows Jonsher power law. The conduction mechanism of LiI-Li 3 PO 4 solid electrolyte follows the quantum mechanical tunneling model.
On the La2/3−xLi3xTiO3/Al2O3 composite solid-electrolyte for Li-ion conduction
Journal of Alloys and Compounds, 2013
An effective ceramic processing route including tape casting and relatively low-temperature calcination has been adopted to fabricate La 0.56 Li 0.33 TiO 3 (LLTO)/Al 2 O 3 composite electrolytes. Correlation among additional amount of Al 2 O 3 , microstructure and Li-ion conductivity of the composites is examined and evaluated. What is most interesting from X-ray diffraction and transmission electron microscopy is that LiAl 5 O 8 phase is found to form in the LLTO/Al 2 O 3 composites during calcination. The present study indicates that the presence of LiAl 5 O 8 has a beneficial effect of increasing ionic conductivity and decreasing activation energy. It was observed that the LLTO/10 wt% Al 2 O 3 composite electrolyte exhibits a higher conductivity at bulk ($6 times) and grain boundary ($3 times) compared to pure LLTO at room temperature. An Arrhenius temperature dependence of Li-ion motion in this composite electrolyte is obtained, displaying low activation energy of 0.17 and 0.37 eV for bulk and grain boundary conduction, respectively.
Physica B: Condensed Matter, 2016
Li 1.3 Al 0.3 À x Sc x Ti 1.7 (PO 4) 3 (LASTP) (for concentrations x ¼ 0.01, 0.03, 0.05 and 0.07) system was prepared using solid state reaction. These ceramic samples were characterized using X-ray diffraction, EDX, SEM, density and DTA-TGA measurements. The electrical properties were studied in the frequency range of 20 MHz to 1 Hz and in the temperature range 303-423 K, using the impedance spectroscopy. The effect of systematic variation of scandium in the LATP lattice has been investigated. The formation of impurity phases has been discussed and found to be detrimental for Li þ conductivity. The non Debye behavior observed in modulus spectra is attributed to local inhomogeneities and impurity phases.