| 초록 |
The lithium ion secondary battery is an enabling technology for portable electronic devices. The ion transporting properties of poly(ethylene oxide) (PEO) have been studied as polymer electrolytes for lithium ion conduction in lithium ion batteries, due to its ability of lithium ion solvation. However, PEO is semi-crystalline polymer and the ionic conduction occurs mostly in the amorphous phases, so the molecular design to control the segmental motion should be one of the most effective approaches to improve the ionic conductivity of such polymer materials. Siloxanes are low Tg materials and electrochemically and thermally stable. In comparison with the conventional carbonate liquid electrolyte (EC, PC), siloxanes comprised by oligo(ethylene oxide) as electrolyte will not make carbonate bond dissociation in cell cycle, which is the potential risk in batteries. And cyclic forms of siloxanes will have very similar boiling points but lower viscosities and vapor pressures in comparison with those of linear forms. In this regard, oligomeric PEO chains have been grafted onto cyclosiloxanes via allylation and hydrosilylation. In this study, substituted cyclosiloxanes with oligo(ethylene oxide) chains were synthesized, and their thermal properties and lithium ion conductivities of thin films were investigated. |
