Patra Sudeshna, Thakur Pallavi, Soman Bhaskar, Puthirath Anand B, Ajayan Pulickel M, Mogurampelly Santosh, Karthik Chethan V, Narayanan Tharangattu N
Tata Institute of Fundamental Research - Hyderabad Sy. No. 36/P, Gopanapally village, Serilingampally Mandal Hyderabad-500107 India
Department of Materials Science and Nanoengineering, Rice University Houston TX 77005 USA.
RSC Adv. 2019 Nov 26;9(66):38646-38657. doi: 10.1039/c9ra08003a. eCollection 2019 Nov 25.
Polymer based solid electrolytes (SEs) are envisaged as futuristic components of safer solid state energy devices. But the semi-crystalline nature and slow dynamics of the host polymer matrix are found to hamper the ion transport through the solid polymer network and hence solid state devices are still far beyond the scope of practical application. In this study, we unravel the synergistic roles of Li salt (LiClO) and two different polymers - polyethylene oxide (PEO) and polydimethyl siloxane (PDMS), in the Li ion transport through their solid blend based electrolyte. A detailed study using dielectric spectroscopy and thermo-mechanical analysis is conducted to understand the tunability of the PEO chain dynamics with LiClO and the mechanism of hopping of Li ions by forming ion pairs with oxygen dipoles on the PEO backbone is established. Despite the lack of PDMS's capability to solvate ions and promote ion transport directly, its proper mixing within the PEO host matrix is demonstrated to enhance ion transport due to the influence of PDMS on the segmental dynamics of PEO. A detailed molecular dynamics study supported by experimental validation suggests that even inert polymers can affect the dynamics of the active host matrix and increase ion transport, leading to next generation high ionic conductivity solid matrices, and opens new avenues in designing polymer based transparent electrolytes.
基于聚合物的固体电解质（SEs）被设想为更安全的固态能量装置的未来组件。但发现主体聚合物基体的半结晶性质和缓慢动力学阻碍了离子通过固体聚合物网络的传输，因此固态装置仍远未达到实际应用的范围。在本研究中，我们揭示了锂盐（LiClO）和两种不同聚合物——聚环氧乙烷（PEO）和聚二甲基硅氧烷（PDMS）在锂离子通过其基于固体共混物的电解质传输中的协同作用。进行了一项使用介电谱和热机械分析的详细研究，以了解LiClO对PEO链动力学的可调性，并建立了锂离子通过与PEO主链上的氧偶极形成离子对进行跳跃的机制。尽管PDMS缺乏溶剂化离子和直接促进离子传输的能力，但由于PDMS对PEO链段动力学的影响，其在PEO主体基质中的适当混合被证明可增强离子传输。一项由实验验证支持的详细分子动力学研究表明，即使是惰性聚合物也可以影响活性主体基质的动力学并增加离子传输，从而产生下一代高离子电导率固体基质，并为设计基于聚合物的透明电解质开辟了新途径。
