Ferroelectric Materials as a Ceramic Filler in Solid Composite Polyethylene Oxide-Based Electrolytes

Abstract

cation and the spontaneous polarization of the ferroelectric ceramics. Also, the interfacial stability between ferroelectric ceramics added to composite polymer electrolytes and a lithium metal electrode is reported and discussed in terms of applications for lithium batteries. ExperimentalAll the polymer electrolytes described here were prepared by the solvent-casting technique using tetrahydrofuran (THF) as a carrier solvent. High-molecular-weight (Mw ϭ 6 ϫ 10 5 g/mol) PEO (Aldrich Chemical) and Li salts [LiClO 4 (Aldrich Chemical), LiBF 4 (Aldrich Chemical), LiPF 6 (Aldrich Chemical), LiCF 3 SO 3 (Aldrich Chemical), or Li[CF 3 SO 2 ) 2 N] (Fluka Chemika) were used as received.Barium titanate powders (Aldrich Chemical (0.6 to 1.2 m) and Osaka National Research Institute (1.8, 0.5, and 0.1 m) were dried under vacuum at 100ЊC for 24 h just prior to use. Lead titanate powders (Osaka National Research Institute) were calcined at 600ЊC for 6 h and then dried under vacuum at 200ЊC for 12 h. Lithium niobate powders (Aldrich Chemical) were dried under vacuum at 200ЊC for 12 h. Strontium titanate powders (Osaka National Research Institute) were calcined at 900ЊC for 12 h and then dried under vacuum at 200ЊC for 12 h. TiO 2 powders (Aldrich Chemical) were dried under vacuum at 150ЊC for 12 h just prior to use. X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to characterize ferroelectric ceramic powders. The characteristics of the ceramic particles used in this experiment are summarized in Table I. The BaTiO 3 with a particle size of more than 0.5 m showed a phase transition from the ferroelectric tetragonal phase to the paraelectric cubic phase at temperatures of 390-396 K. The amount of the endothermic heat absorbed by the phase transition depended on the particle size. The fine BaTiO 3 with 0.1 m indicated no phase transition. The amount of the endothermic heat is a measure of the content of the ferroelectric phase.Preparation of the composite electrolyte samples involved the dispersion of the selected ceramic powders and of the lithium salt in THF, followed by the addition of the polymer component (PEO). When the slurry was completely homogenized, it was heated and stirred simultaneously. The slurry gradually became a gel. The gel was cast onto a flat polytetrafluoroethylene sheet. The solvent was allowed to evaporate slowly at 40ЊC for 24 h; then the sheet was held at room temperature under vacuum for 48 h. These procedures yielded homogeneous and mechanically stable membranes with an average thickness of 300 m. All the steps in these preparation procedures and the experiments were carried out in an inert-gas atmosphere or under vacuum.

Fabrication and electrochemical performance of lithium polymer battery using mesoporous silica/polymer hybrid electrolyte

“…5),12), 13) In this study, we used mesoporous silica (MPS)/Li + conductive PEO (Li-PEO) hybrid electrolytes in lithium polymer batteries to improve the mechanical strength of the SPE. MPS is composed of stacked SiO 2 channels arranged in a hexagonal array with pore sizes ranging from 2 to 10 nm.…”

Aqueous Lithium-Air Rechargeable Batteries

“…We also found that the addition of nanosize BaTiO 3 (0.1 µm) was effective to reduce the interface resistance between lithium metal and PEO 10 LiTFSI. 19,20 The interface resistance between lithium metal and PEO 10 LiTFSI (ca. 25 ³ cm 2 ) was constant for 10 days at 80°C.…”

“…Shin et al reported interesting results for a PEO-based polymer electrolyte with ionic liquids. 33,34 A composite polymer electrolyte of PEO 20 LiTFSI and N-butyl-N-methylpyrrolidum-TFSI exhibited high electrical conductivity at a moderate temperature and good stability with lithium metal. The addition of RTIL into the polymer electrolyte results in enhancement of the electrical conductivity.…”

Ion Conducting Behaviour of Nano Dispersed Polymer Gel Electrolytes Containing NH4PF6

“…The addition of polymer to salt solution increases the viscosity, which is generally accompanied by a small decrease in conductivity [12]. In solvent free polymer electrolytes, the addition of micron size inorganic fillers such as fumed silica, zeolite, Al 2 O 3 , TiO 2 , etc., has been reported to result in an improvement in the electrode-electrolyte interfacial stability, conductivity along with an improvement in mechanical properties of electrolytes [13][14][15][16]. The aim of the present work is to study the effect of nano size fumed silica on the properties of polymer gel electrolytes.…”