Composite polymer electrolytes fillers

Key words composite polymer electrolytes, fillers, lithium batteries, PEMFC, electrochemical property, HT-PEMFC. 

Another kind of modification of PEO involves the concept of composite polymer electrolytes [33, 37-38, 138-144]. These include the use of inorganic fillers such asNASICON [138],/1-alumina [139], glassy fillers [139] y-LiA 02 [140-143]... 

Most of the recent papers deal with PEO and other polymers incorporated with inert fillers [30, 40-53], which also have poor mechanical properties. These films have to be hardened by chemical or physical curing, which leads to high processing costs. Recent studies reveal that only composite polymer electrolytes incorporated with inorganic filler can offer mechanically strong and safe batteries with improved electrolyte-electrode compatibility. One of the functions of the fillers is also the reduction of crystallinity of the host matrix. 

Kim, M., Lee, L., Jung, Y., Kim, S. (2013). Study on ion conductivity and crystallinity of composite polymer electrolytes based on poly(ethylene oxide)/poly(acrylonitrile) containing nano-sized AI2O3 Fillers, Ngng gi lfjmgteclmgl., 13(12), 7865-7869. 

For the composite polymer electrolytes, the conductive carbonaceous filler must be below the electrical percolation threshold, due to the need to obtain an electronically insulating material with suitable ionic conductivity. These fillers are also used to improve the thermal stabilization and serve as mechanical reinforcement to improve the electrolyte/ electrode compatibility. CNT/P(VDF-TrFE) composites showed higher porosity and electrolyte uptake compared to the pristine polymer. CNT also contributed to increase ionic conductivity (2.6 xlO S cm , 0.1 wt.% CNT) and diminished its variations with temperature. 

Pitawala et al., (2007) studied the combined effect of both plasticizer and nano-ceramic filler on the thermal behavior and conductivity of (PEO)g-lithium trifiuoromethanesulphonate (LiCFjSOj or LiTf) composite polymer electrolyte. The formula (PE0)gLiCFjS03 denotes the chemical composition of the polymer-salt complex in which 9 is the molar ratio of (ethylene oxide (EOl/LiCF SOj). According to their work, addition of 15 wt% Aip lowered the and T of (PEO)gLiTf from 58 °C and °Cto 51 °C and -50 °C, respectively and the con-... 

In view of the many parameters involved viz. blend composition, types of plasticizer, and nano-fillers, grain size, and dispersion and so on, an in-depth study of the conductivity mechanism of the electrolyte system and an understanding of the characteristic and behavior of each additive are important in the pursuit of an appUcable PEO/PMMA composite polymer electrolyte system. 

The PVA (Mw 1,25,000, Aldrich), Orthophosphoric acid (H PO ) (Ranbaxy, India) and nano particles of AEj03 (50 mn. Sigma) were used for the preparation of NCPE films. The films of Solid Polymer Electrolyte (PVA + HjPO ) and Nano Composite Polymer Electrolyte (PVA + H3PO + Al Oj) in different filler wt% ratios were prepared by solution cast technique. Grantdes of PVA were dissolved in triply distilled water and stirred magnetically for 10-12 hr to obtain a clear and homogeneous solution. A known amount of H3PO was added to it and stirred continuously until a viscous solution was obtained. A part of solution was poured into the Teflon Petri dishes to get SPE thin film and in another part of the solution, nano-sized Al Oj was added in different wt % to get NCPE thin films. The prepared thin films were rinsed with benzene/methanol to remove any volatile impurities present in it. 

In order to manufacture a composite polymer electrolyte for a lithium secondary battery, a copolymer of vinylidene fluoride and hexafluoropropylene is casted with an conducting inorganic filler. 

Y.G. Lee, K.M. Kim, K.S. R5m, and S.H. Chang, Lithium cationic single-ion conducting filler-containing composite polymer electrolyte for lithium secondary battery and metiiod of manufacturing the same, US Patent 7 399 556, assigned to Electronics and Telecommunications Research Institute (Daejeon, KR), July 15,2008. 

Key words composite polymer electrolyte, lithium battery, all solid state battery, surface treatment, ceramic filler, polymer-in-ceramic composite. 

MELLANDER, B., 2003. Effect of concentration and grain size of alumina filler on the ionic conductivity enhancement of the (PE0)9LiCF3S03 Al203 composite polymer electrolyte. Journal of Power Sources, 119-121,409-414. 

In the 1980s, several authors proposed the use of composite polymer electrolytes. The solutions they proposed depended on the electrochemical application, i.e. lithium batteries, fuel cells, etc., which determined the properties required. This chapter reviews the development and properties of composite polymer electrolytes used in lithium batteries and proton exchange membrane fuel cells (PEMFC). The effects of fillers on electrolyte properties are discussed in terms of electrochemical performance, and also in terms of polymer matrix morphology and dynamics. Data from the literature are compared in order to determine the effects of the manufacturing... 

The aim of the first part of this chapter is to present recent research on composite polymer electrolytes, both solid and gel, in order to try to clarify the effect of fillers on ionic conduction, transference number, the polymer crystallisation process, mechanical properties and interface properties in polymer electrolytes. 

Composite polymer electrolytes based on poly(ethylene oxide) and non-ionic fillers... 

The current challenge for PEMFC is to raise the working temperature above 80 °C. Composite membranes are a potential solution. The addition of inorganic fillers induces important improvements in water retention at high temperature, conductivity, cell resistivity, mechanical properties, etc. These improvements are related to filler concentration, structure and size, interfaces, polymer matrix and membrane characteristics. It is difficult to compare these ionomer/fiUer composites because their performances depend on the electrolyte preparation and testing conditions (RH, temperature, etc.). H2/02(air) cells based on composite polymer electrolytes have been successfully operated at temperatures up to 120 °C under ambient pressure, and up to 150 °C under pressures of 3-5 atm, but more research... 

Most elastomers require reinforcing fillers to function effectively, and NMR has been used to characterize the structure of such composites as well. One examples is the adsorption of chains onto filler surfaces, -and the strong absorption of these chains into bound rubber —for example, PDMS immobilized onto high surface area silica. - Another example is the use of NMR to image the filler or polymer itself. ° NMR has also been used to study the phase separation and order of water molecules and silanol groups in polysiloxane networks and the activation of transport and local dynamics in polysiloxane-based salt-in-polymer electrolytes. ... 

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