Thick-films of garnet-type lithium ion conductor prepared by the Aerosol Deposition Method: The role of morphology and annealing treatment on the ionic conductivity

• Published in: Journal of power sources 2017-09, Vol.361, p.61-69
• Main Authors: Hanft, Dominik, Exner, Jörg, Moos, Ralf
• Format: Article
• Language: English
• Subjects: Aerosol Deposition Method (ADM); Film morphology; Garnet-type LLZO; Lithium ion battery; Solid electrolyte; Vacuum kinetic spraying (VKS)
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.06.061

We fabricated thick films of cubic garnet solid electrolyte AlyLi7-3y-zLa3Zr2-zTazO12 (ALLZTO) by the Aerosol Deposition Method (ADM). Due to the room temperature impact consolidation (RTIC) mechanism, the films become dense. A thermal post-treatment of the film revealed the morphological and process-related impact on the ionic conductivity. As-deposited films show a reduced conductivity around 2·10−7 S/cm. Using electrochemical impedance spectroscopy and high-temperature X-ray diffraction, we found the lattice distortion and nano-crystallinity of the films to be the decisive effect for the conductivity reduction. In our case, post-deposition annealing at 400 °C lead to an increase of the ionic conductivity to 2·10−5 S/cm. With a beginning of sintering at 600 °C, the conductivity successively increased further, reaching values of 7·10−5 S/cm. •Thick films of Li7La3Zr2O12 laced with Al and Ta prepared at room temperature.•Aerosol Deposition following the room temperature impact consolidation mechanism.•Nano-crystallinity and micro strain in as-deposited films reduce ionic conductivity.•Decreases of strain and increases of crystallite size through annealing.•Recovery of ionic conductivity and reduction of activation energy through annealing.