Md Yusuf Ali1,Hans Orthner1,Hartmut Wiggers1,2
Institute for Energy and Materials Processes – Reactive Fluids; University of Duisburg-Essen1,Center for Nanointegration Duisburg-Essen2
Md Yusuf Ali1,Hans Orthner1,Hartmut Wiggers1,2
Institute for Energy and Materials Processes – Reactive Fluids; University of Duisburg-Essen1,Center for Nanointegration Duisburg-Essen2
Due to its safety, low cost, and high energy density characteristics, solid-state lithium-ion batteries have been recognized as one of the most promising candidates for future green energy storage technologies. Electrolytes made of polymers and ceramics are prime candidates to expand the use of lithium metal batteries. Single-ion conducting polymers can lessen polarization and the formation of lithium dendrites, but they eventually become extremely inflexible mechanically, necessitating mobilizers such as organic solvents to move Li ions. Inhomogeneous solvent dispersion and the accompanying preferred Li transport paths may result in favored locations for Li plating, adding mechanical stress and maybe even causing early cell short-circuits. However, ceramic-based electrolytes, such as Li<sub>1.3</sub>Al<sub>0.3</sub>Ti<sub>1.7</sub>(PO<sub>4</sub>)<sub>3</sub> (LATP) NASICON, are renowned for their superior dendritic growth inhibitor and high-temperature adaptability. In contrast to other wet synthesis methods, spray-flame synthesis is affordable and incredibly simple to scale up with excellent purity, thus we looked into the best conditions to synthesize LATP solid electrolyte. We found that nitrates are better than acetates as metal precursors, and excess Li is indeed necessary in precursor solution to synthesize pure phase LATP. We characterized the resulting nanoparticles by state-of-the-art techniques such as XRD, XPS, TEM, Raman Spectroscopy etc. The as-prepared spray flame synthesized nanoparticles are found to be TiO<sub>2</sub> and with Li carbonate on the surface as confirmed by XPS, and it requires a high-temperature calculation (~750 °C) to finally form LATP phase. However, the ionic conductivity of LATP phase samples (0.049 mS/cm) were not up to the industrial standard. To further increase the ionic conductivity of LATP electrolytes the Al<sup>3+</sup> (0.535 Å) substitution with similar charge Y<sup>3+ </sup>(0.93 Å) was carried outLi<sub>1.3</sub>Al<sub>0.3</sub>Y<sub>0.3-x</sub>Ti<sub>1.7</sub>(PO<sub>4</sub>)<sub>3</sub> (x= 0 to 1.5). Moreover, the large size of Y<sup>3+</sup> distorts the NASICON structure and provides broad passage for the Li<sup>+</sup> ion to pass through. The enhanced electrochemical characteristics of LATP samples make it possible to see how Y doping affects the samples. The synthesized sample (x=0.1 doped) has a conductivity of around 0.000092 mS/cm. Because of as synthesized TiO<sub>2</sub> phase. However, after calcining at 700 °C, a rise in conductivity (0.006042 mS/cm) can be seen for the sample due to phase transformation to LATP. Further increment in ionic conductivity was done while simultaneously increasing the grain boundary of the pellet. And the final conductivity was reached as high as 0.87 mS/cm which almost reaches the milestone for NASICON solid state electrolytes.