Amorphous and perovskite Li3xLa(2/3)−xTiO3 (thin) films via chemical solution deposition: solid electrolytes for all-solid-state Li-ion batteries

Abstract

Thin films of amorphous and crystalline perovskite Li 3x La (2/3)-x TiO 3 (LLT) (x = 0.117) are prepared by means of aqueous chemical solution deposition onto rutile TiO 2 thin films as an anode, yielding an electrochemical half-cell. The Li-ion conductivity of the pinhole free, amorphous LLT thin film (90 nm thick) is 3.8 9 10 -8 S cm -1 on Pt and 1.3 9 10 -8 S cm -1 on rutile TiO 2 , while measuring perpendicular to the thin film direction with impedance spectroscopy. Grazing angle attenuated total reflectance-Fourier transform infrared spectroscopy shows that all organic precursor molecules have been decomposed at 500°C. In addition, in situ (heating) X-ray diffraction analysis shows that phase pure crystalline perovskite LLT (x = 0.117) is formed on top of the rutile TiO 2 anode at 700°C. Furthermore, thickness control is possible by varying the precursor solution concentration and the number of deposition cycles. The current study presents a promising synthesis route to develop all-solid-state battery devices based on multi-metal oxide materials using aqueous precursor chemistry.

Low-temperature fabrication of lithium aluminum oxide phosphate solid electrolyte thin films from aqueous precursors

“…Most closely related to the work herein is that of van den Ham et al, who reported an aqueous precursor route to thin lms of an amorphous lithium lanthanum titanate perovskite ISE. 24 These authors used an aqueous citrate-peroxo-Ti(IV) precursor, which required annealing temperatures of 500 C for complete decomposition and elimination of citrate. Here we demonstrate that PIC using nitrate and phosphate precursors can be used to synthesize dehydrated, smooth, uniform LiAlPO lms at temperatures as low as 275 C.…”

From liquid to thin film: colloidal suspensions for tungsten oxide as an electrode material for Li-ion batteries

“…Besides LiPON, 24,25 Li-ion conducting silicates 26,27 and few a garnets; [28][29][30] thin lm solid electrolytes have a limited electrochemical stability at low voltages. 1,31 Thus the high voltage WO 3 negative electrode opens up a broader range of applicable solid electrolyte materials such as perovskite Li 3x La (2/3)À2x TiO 3 (LLT) [32][33][34][35][36] and titanium-containing NASICON. 37,38 Finally, titanium nitride (TiN) is opted as an alternative for the rare and expensive Pt current collector 25,34 since it combines good electronic conductivity with Li-ion blocking properties.…”

“…1,31 Thus the high voltage WO 3 negative electrode opens up a broader range of applicable solid electrolyte materials such as perovskite Li 3x La (2/3)À2x TiO 3 (LLT) [32][33][34][35][36] and titanium-containing NASICON. 37,38 Finally, titanium nitride (TiN) is opted as an alternative for the rare and expensive Pt current collector 25,34 since it combines good electronic conductivity with Li-ion blocking properties. 39 Unfortunately, TiN tends to oxidize under oxidative annealing conditions.…”

Wet-Chemical Synthesis of 3D Stacked Thin Film Metal-Oxides for All-Solid-State Li-Ion Batteries

“…Notably, the choice was made to prepare LLT in its amorphous state. Previous studies indicated that crystallization of the highly Li + conductive perovskite lithium lanthanum titanium solid-electrolyte leads to serious issues regarding cracks and pinholes [ 42 , 43 ]. Therefore, at the cost of a lower Li-ion conductivity of 10 −8 S·cm −1 , the amorphous form of this material is chosen.…”

“…Therefore, at the cost of a lower Li-ion conductivity of 10 −8 S·cm −1 , the amorphous form of this material is chosen. This leads to enhanced morphology, which is of crucial importance to prevent short circuits over the electrolyte layer [ 43 ]. In addition, the more mild annealing conditions required for the amorphous phase eases integration with other materials, which is crucial for 3D all-solid-state Li-ion batteries.…”