| Abstract
| - A self-assembling ABA triblock copolymer complexed with lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) salt showed ion conductivities (σ) approaching 10-5 S/cm at 20 °C.The block copolymer had endblocks of polyethylene (PE) and midblocks of poly(ethylene oxide-co-propylene oxide) (PEOPO) and formed physical networks with PEOPO chains interconnected by crystalline PE domains. Thermal analysis showed a PEOPO glass transition at−68 °C and a PE melting point at 100 °C. When the melting region of the PE phase wasreached, σ of the electrolytes was found to increase sharply to attain the same level as thecorresponding electrolyte based on the neat PEOPO precursor block. Furthermore, the levelof σ of the block copolymer electrolytes was found to be strongly dependent on the thermalhistory of the samples, and they showed a hysteresis behavior where σ increased by a factorof ≈3 after annealing above 110 °C. This may be explained by a reduction of the chainconstraints of the PEOPO blocks in the physical network after annealing. The electrolytesbehaved essentially like thermoplastics and were soft, tacky, self-supporting materials atroom temperature.
|
