Chimney-Shaped Phase Diagram in a Polymer Blend Electrolyte
Chimney-Shaped Phase Diagram in a Polymer Blend Electrolyte
复制标题
聚合物共混电解质中的烟囱形相图
DOI：
10.1021/acsmacrolett.3c00285
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发表时间：
2023
影响因子：
7.015
通讯作者：
Balsara, Nitash P.
中科院分区：
文献类型：
--
作者：
Shah, Neel J.;Shalaby, Marwan;He, Lilin;Wang, Xin;Deslandes, David;Garetz, Bruce A.;Balsara, Nitash P.
使用光和小角中子散射（SANS）实验相结合来确定包含聚（环氧乙烷）（PEO）/聚（甲基丙烯酸甲酯）（PMMA）/双（三氟甲磺酰基）亚胺锂（LiTFSI）的聚合物共混电解质的相行为。固定温度 (110 °C) 下的结果以 PEO 浓度与盐 (LiTFSI) 浓度关系图的形式呈现。在不存在盐的情况下，该共混物在所有 PEO 浓度下均可混溶。添加盐后，贫 PEO 聚合物共混电解质中会出现不混溶区域；富含 PEO 的混合物在大多数盐浓度下仍可混溶。狭窄的不混溶区域伸入混溶区域，使相图呈现烟囱状外观。这些数据在质量上与 Flory-Huggins 理论的简单扩展一致，该理论具有依赖于成分的 Flory-Huggins 相互作用参数 χ，该参数是独立于均质混合电解质的 SANS 数据确定的。像我们获得的相图是通过自洽场论计算来预测的，该计算解释了离子之间的相关性。这些理论与测量的 χ 之间的关系仍有待建立。
The phase behavior of polymer blend electrolytes comprising poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA)/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was determined using a combination of light and small angle neutron scattering (SANS) experiments. The results at a fixed temperature (110 °C) are presented on a PEO concentration versus salt (LiTFSI) concentration plot. The blends are miscible at all PEO concentrations in the absence of salt. With added salt, a region of immiscibility is obtained in PEO-lean polymer blend electrolytes; blends rich in PEO remain miscible at most salt concentrations. A narrow region of immiscibility juts into the miscible region, giving the phase diagram a chimney-like appearance. The data are qualitatively consistent with a simple extension of Flory–Huggins theory with a composition-dependent Flory–Huggins interaction parameter, χ, that was determined independently from SANS data from homogeneous blend electrolytes. Phase diagrams like the one we obtained were anticipated by self-consistent field theory calculations that account for correlations between ions. The relationship between these theories and measured χ remains to be established.