PMMA-based Polymer Electrolytes Research Articles

XRD Measurement for Particle Size Analysis of PMMA Polymer Electrolytes with SiO2

PMMA-based polymer electrolytes with LiCF3SO3 lithium salt, EC plasticizer, and SiO2 filler are prepared using the solution cast method. SiO2 filler sizes at 10 ?m and 63 ?m are used to estimate the particle size in the polymer electrolytes syste

(Invited) Solvate Ionic Liquids and Their Polymer Electrolytes: Possible Beyond LIB Electrolytes

Certain molten solvates of Li salts can be regarded as solvate ionic liquids (SILs). A typical example is equimolar mixtures of glymes (G3: triglyme and G4: tetraglyme) and Li[TFSA]([TFSA]=[NTf2]) ([Li(glyme)][TFSA]). The amount of free glyme is a trace in [Li(glyme)][TFSA], and thereby can be regarded as solvate ionic liquids. Unlike conventional electrolytes, the solvation of Li+ by the glyme forms stable and discrete solvate ions ([Li(glyme)]+) in the solvate ionic liquids. The electrochemical oxidation of glyme in [Li(glyme)][TFSA] is greatly enhanced due to the donation of lone pairs of ether oxygen atoms to the Li+ cation, resulting in the HOMO energy level lowering of a glyme molecule. This anomalous Li+ solvation induces interesting transport properties when interfacial electrochemical reactions proceed, which is not transport of solvated ions based on Stokes’ law but a ligand (solvent)-exchange transport. Li+-intercalated graphite was electrochemically formed in [Li(G3)1][TFSA]. In contrast, the cointercalation of G3 and Li+ (intercalation of solvate [Li(G3)1]+ cation) into graphite occurred in [Li(G3) x ][TFSA] electrolytes containing excess G3 (x > 1). In the solvate ionic liquid, the activity of the free solvent is very low, which would make the solvate ion unstable and the desolvation possible at the interface. Another intriguing aspect of the solvate ionic liquids is unusual solubility, which leads to the stable operation of the Li–S battery due to very low solubility of the discharge products (Li2S x ). The theoretical capacity of the S cathode is 10 times higher than that of conventional cathode materials used in current Li–ion batteries. However, Li–S batteries suffer from the dissolution of lithium polysulfides, which are formed by the discharge reaction of the S cathode. In the SILs, [Li(glyme)][TFSA], both cations and anions are weakly coordinating ions with low Lewis acidity and basicity, respectively. The [Li(glyme)][TFSA] molten complexes do not readily dissolve other ionic solutes due to the weak coordinating nature of the cation and anion, which leads to the stable operation of the Li–S battery.Furthermore, polymer electrolytes composed of ABA-triblock copolymers and [Li(glyme)][TFSA] SILs are proposed to simultaneously achieve high ionic conductivity, thermal stability, and a wide potential window. Different block copolymers, consisting of a SIL-incompatible A segment (polystyrene, PSt) and SIL-compatible B segments (poly(methyl methacrylate) (PMMA) and poly(ethylene oxide) (PEO)) are utilized. The SILs can be solidified with the copolymers through physical crosslinking by the self-assembly of the PSt segment. The thermal and electrochemical properties of the polymer electrolytes are significantly affected by the stability of the [Li(glyme)]+ complex in the block copolymer B segments, and the preservation of the SILs contributes to their thermal stabilities and oxidation stabilities greater than 4 V vs. Li/Li+. The [Li(glyme)]+ complex cation is unstable in the PEO matrix, whereas the complex structure of [Li(glyme)]+ is stable in the PMMA-based polymer electrolyte. Intriguing points of the PMMA-based polymer electrolytes are decoupled ion transport from segmental motion of the matrix polymer. By using the PMMA-based polymer electrolytes, a 4-V class Li batteries with a LiCoO2 cathode and a Li metal anode can be stably operated; in contrast, this is not possible using the PEO-based electrolyte.Recently, we find that Li+ hopping conduction, which cannot be explained by conventional Stokes law, emerges in certain highly concentrated molten solvate electrolytes. Li+ diffuses faster than the solvent and anion, and thus the evolution of Li+ hopping conduction is confirmed, which leads to a higher Li+ transference number. Possible application of these new electrolytes will also be discussed.

Investigation of Ionic Conduction and Morphological Properties of PMMA-Based Polymer Electrolytes Containing Lithium Iodide

In this study, the two systems of polymethylmethacrylate (PMMA) based polymer electrolyte films have been prepared by the solution casting technique. Lithium iodide (LiI) and ethylene carbonate (EC) were used as inorganic salt and plasticizer, respectively. The highest room temperature conductivity for the plasticized system and unplasticized system is 4.42 x 10-5Scm-1and 4.37 x 10-6Scm-1, respectively. The conductivity-temperature dependence studies have been performed on these films in the temperature range of 303 K to 373 K. It can be observed that the logσversus 1000/T plots obey the Arrhenius rule and VTF rule for the plasticized film and unplasticized film, respectively [1-3]. The surface morphology of the plasticized and unplasticized films was observed by using scanning electron microscope (SEM).

Ionic Conductivity and Dielectric Studies of Chitin Nanofiber (CNF) Incorporated PMMA Based Polymer Electrolytes

Chitin nanofibers (CNF) are synthesized from shrimp cell chitin by stepwise purification and acid hydrolysis method. PMMA based polymer electrolytes complexed with LIN (CF3SO2)2 and chitin nanofibers as nanofiller have prepared by membrane hot-press technique. The prepared composite electrolytes are subjected to FT-IR, ac impedance, dielectric and modulus analyses. The incorporation of nanofiller in the polymer matrix increases the conductivity by an order of magnitude compared with filler free electrolytes. The complexation behavior of the composite polymer electrolytes are investigated by ATR FT -IR spectroscopy. The electric modulus analysis and dielectric studies of polymer electrolytes revealed that the non Debye dielectric relaxation nature.

Effect of ceramic oxide on PMMA based polymer electrolyte systems : Rajendran, S., Uma, T., Alagappa University, Karaikudi, India in materials letters, vol 45, issue 3, 2000

Glycerol assisted gel combustion route (GGCR) was used for the synthesis of nano-crystalline inverse spinel LiNiVO4 powders, with metal nitrates, citric acid and glycerol for three different total metal ions to glycerol ratios (M/G) as 1:1, 1:2 and 1:3. In this study, the effect of total metal ion to glycerol ratio on the formation of the nano-crystalline LiNiVO4 phase was investigated and discussed. The thermal behavior and structural coordination of the as prepared as well as the calcined polymeric intermediates at different temperatures were investigated, respectively, using the DSC and FTIR measurements. The microstructure of the polymeric intermediates was identified by taking the scanning electron microscopy (SEM) pictures. The formation of the inverse spinel LiNiVO4 phase, obtained from the calcined intermediates, was confirmed by comparing the observed X-ray diffraction spectra with the respective JCPDS standard. The crystallite size was calculated using the Scherrer's formula and the smallest crystallite size of 39 nm was observed for the LiNiVO4 powders obtained from the polymeric intermediate, calcined at 450 °C for 12 h, synthesized using the GGCR with M/G=1:1.

Effect of ceramic oxide on PMMA based polymer electrolyte systems

The polymer electrolyte films obtained by the addition of zirconium oxide to poly (methyl methacrylate) have been investigated by FTIR and complex impedance spectroscopy. FTIR studies indicate complex formation between the polymer, salt, plasticizer and that the complex remains mainly in the amorphous phase. The temperature dependence of the conductivity of the polymer films seems to obey the VTF relation. The conductivity values are presented and the results are discussed.