October 2023
Title: “Transport Properties and Local Ions Dynamics in LATP-Based Hybrid Solid Electrolytes”
Written by: Nicola Boaretto, Pedram Ghorbanzade, Haritz Perez-Furundarena, Leire Meabe, Juan Miguel López del Amo, Isuru E. Gunathilaka, Maria Forsyth, Jörg Schuhmacher, Andreas Roters, Sergey Krachkovskiy, Abdelbast Guerfi, Michel Armand, María Martinez-Ibañez.
Abstract: Hybrid solid electrolytes (HSEs), namely mixtures of polymer and inorganic electrolytes, have supposedly improved properties with respect to inorganic and polymer electrolytes. In practice, HSEs often show ionic conductivity below expectations, as the high interface resistance limits the contribution of inorganic electrolyte particles to the charge transport process. In this study, the transport properties of a series of HSEs containing Li(1+x)AlxTi(2–x)(PO4)3 (LATP) as Li+-conducting filler are analyzed. The occurrence of Li+ exchange across the two phases is proved by isotope exchange experiment, coupled with 6Li/7Li nuclear magnetic resonance (NMR), and by 2D 6Li exchange spectroscopy (EXSY), which gives a time constant for Li+ exchange of about 50 ms at 60 °C. Electrochemical impedance spectroscopy (EIS) distinguishes a short-range and a long-range conductivity, the latter decreasing with LATP concentration. LATP particles contribute to the overall conductivity only at high temperatures and at high LATP concentrations. Pulsed field gradient (PFG)-NMR suggests a selective decrease of the anions’ diffusivity at high temperatures, translating into a marginal increase of the Li+ transference number. Although the transport properties are only marginally affected, addition of moderate amounts of LATP to polymer electrolytes enhances their mechanical properties, thus improving the plating/stripping performance and processability.
Keywords: Composite polymer electrolytes, conduction mechanism, hybrid solid electrolytes, LATP, NASICON, solid-state batteries, transport properties.
Orginal article: https://onlinelibrary.wiley.com/doi/10.1002/smll.202305769
