LiSn2(PO4)3-based polymer-in-ceramic composite electrolyte with high ionic conductivity for all-solid-state lithium batteries

• Published in: Journal of solid state electrochemistry 2020, Vol.24 (10), p.2407-2417
• Main Authors: Ahmed, Shadab Ali, Pareek, Tanvi, Dwivedi, Sushmita, Badole, Manish, Kumar, Sunil
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Ceramics; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Current density; Discharge; Electrochemical analysis; Electrochemistry; Electrode polarization; Electrolytes; Electrolytic cells; Energy Storage; Field emission microscopy; Fourier transforms; Ion currents; Lithium; Lithium batteries; Lithium ions; Lithium manganese oxides; Lithium perchlorates; Low currents; Mathematical analysis; Original Paper; Physical Chemistry; Polymers; Rechargeable batteries; Solid electrolytes; Solid state; Spectrum analysis
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-020-04783-z

In this work, fabrication and electrochemical behavior of polymer-in-ceramic composite electrolytes based on lithium-ion conducting triclinic LiSn 2 (PO 4 ) 3 (LSP) for all-solid-state batteries are reported. The composite ceramic electrolyte (CCE) was fabricated using polymeric salt (PEO+LiClO 4 ) as a filler to the ceramic compound LSP using a simple hot-press technique. The x-ray diffraction and Fourier transform infrared spectroscopy (FTIR) studies were performed to determine the structure of the composite electrolyte. Composite electrolyte containing 30 wt.% PEO+LiClO 4 exhibit the highest conductivity of ~ 3.48 × 10 −5 Scm −1 at 27 °C, which improves to ~ 1.18 × 10 −4 Scm −1 at 60 °C. The low activation energy calculated to be ~ 0.34 eV results from additional mobile lithium-ion in a composite electrolyte. The field emission scanning electron microscopy (FESEM) and energy-dispersive x-ray spectroscopy (EDX) reveals the Li + diffusion route along with the 3D inter-connected LSP-(PEO+LiClO 4 ) interfaces and distribution of polymeric salt to LSP. The ionic and Li + transference numbers calculated by a combination of ac signal and dc polarization were found to be ~ 0.99 and ~ 0.39, respectively. The electrochemical performance of the CCE was tested using the cyclic voltammetry (CV) and galvanostatic charging-discharging (GCD) in symmetric cell employing lithium metal as the electrode. Composite electrolyte exhibited highly reversible lithium stripping/plating behavior at low current density. All-solid-state cells fabricated using LiMn 2 O 4 as the cathode, Li metal as the anode, and the LSP-30 (PEO+LiClO 4 ) as the solid electrolyte deliver a high specific discharge capacity of ~ 103.3 mAhg −1 at a current density of 100 μAcm −2 .