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

摘要

In this work, fabrication and electrochemical behavior ofpolymer-in-ceramiccomposite electrolytes based on lithium-ion conducting triclinic LiSn2(PO4)(3)(LSP) for all-solid-state batteries are reported. The composite ceramic electrolyte (CCE) was fabricated using polymeric salt (PEO+LiClO4) 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 similar to 3.48 x 10(-5)Scm(-1)at 27 degrees C, which improves to similar to 1.18 x 10(-4)Scm(-1)at 60 degrees C. The low activation energy calculated to be similar to 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+LiClO4) 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 similar to 0.99 and similar to 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+LiClO4) as the solid electrolyte deliver a high specific discharge capacity of similar to 103.3 mAhg(-1)at a current density of 100 mu Acm(-2).