Preparation and performance of a novel core-shell Gel Polymer Electrolytes
A novel core-shell latex Gel Polymer Electrolytes (GPE) based on poly (methyl methacrylate-acrylonitrile -styrene) (P(MMA-AN-ST)) was prepared for applications in Li-ion batteries. The structure and the performance of the polymer and the GPE were characterized with FTIR, DSC/TG, TEM, SEM, LSV and CA. It is shown that the copolymer has a high thermal stability up to 320°C and the porous structure of the membrane was formed effectively. As-prepared gel polymer electrolytes exhibits a high ionic conductivity of 3.52×10−3 Scm−1 at 25°C and it is electrochemically stable up to 5.2V (vs. Li). This novel GPE can be potentially applied to the manufacture of PLBs.
Crystallinity and order of poly(ethylene oxide)/lithium triflate complex confined in nanoporous membranes
Abstract The confinement of poly(ethylene oxide), PEO, electrolyte in pores of 13, 35, 55 and 100 nm in diameter in nanoporous alumina membranes was seen to have effects on the ionic conduction properties. Specific conductivity values for the PEO/lithium triflate complex in the 13 and 35 nm pores, for temperatures below the melt temperatures, were increased by a factor of four compared to the non-confined polymer and the 55 and 100 nm pore systems. Thermal analysis data indicate the melting temperature for the PEO electrolyte in the pores is directly proportional to the pore size such that as the pore size of confinement is decreased, the T m decreases as well. The same behavior is seen for the amount of crystallinity, with less crystallinity being observed as the pores become smaller. Perhaps the observed conduction behavior could be attributed to less crystallinity. However, it is known that confinement of polyethers in pores results in stretching and ordering of the backbone and that such ordering can increase ion conduction. This ordering would seem to be the major factor involved in these results. The enhanced conduction only being seen in the 13 and 35 nm pores and not the 55 and 100 nm pores is attributed to the larger size for the latter which allows a more bulk-like behavior with less ordering.
Structure and conductivity of liquid crystal channel‐like linic complexes of taper‐shaped compounds
Molecular packing and electrical conductivity were studied in complexes of alkali trifluoromethanesulphonates with low-molar or polymeric compounds containing both taper-shaped mesogens were esters of either 3,4,5-tris [p-(n-dodecan-l-yloxy) benzyloxy] benzoic acid (I) or 3, 4, 5-tris (n-dodecan-l-yloxy) benzoic acid (II). In the hexagonal columnar liquid crystal phase the tapered mesogens fan out from the centre of the column, with the ionic receptors forming the central channel and the aliphatic tails constituting the continuum matrix. In the case of side-chain polymethacrylates the column core also contains the backbone chain. The DC conductivity σ of unoriented samples increases greatly at the crystal-columnar transition, with only a minor further change upon columnar-isotropic transition. σ was in the range 10−9 − 10−6 in the columnar phase 40–90 °C, whilst the activation energies for conduction were between 28 kcal mol−1 for the crown ether and only 2 kcal mo−1 for the complex of LiCf3SO3 with the non-polymeric ester of tri(ethylene oxide) with I.