Collaborative Research: Thermodynamics and Ion Transport in Hybrid Organic-Inorganic Block Copolymer Electrolytes

非技术性描述：生活越来越多地与电化学能量存储交织在一起，主要是以锂电池的形式。 它们是手机、笔记本电脑、踏板车、电动汽车、家庭、太阳能装置甚至飞机不可或缺的组成部分。 但这些基本的设备有潜在的安全隐患，因为它们携带高度易燃的液体，导致爆炸和火灾。 构建本质安全的可充电锂电池仍然是一个尚未满足的挑战，特别是在开发不可燃电解质（允许电池中电荷流动的材料）以取代当前锂电池中的可燃有机液体电解质方面。 聚合物电解质为易燃液体提供了一种有前途的替代品。 所有以前的研究都考虑了由有机结构单元制成的聚合物。 拟议的工作开始于一种新的方法：合成一种混合聚合物，包括有机和无机的构建块。 这种聚合物自发地形成10纳米宽的交替的有机和无机层（人类头发是100，000纳米宽）。 这种材料的可燃性非常低。有机层传导锂离子，而无机层为聚合物电解质提供机械刚度，这是防止两个电池电极接触和短路电池所必需的特性。 计划中的工作将研究锂离子在复合电解质中的运动和层形成之间的关系。在这个项目上合作的PI也将致力于在加州大学伯克利分校校园的多样性相关的举措，在组织针对高中生在布鲁克林的科学主题的公开讲座，并提供多学科培训，本科生和研究生在他们的机构。技术描述：拟议的工作重点是混合有机-无机嵌段共聚物和锂盐的混合物。 官能化的多面体低聚倍半硅氧烷（POSS）颗粒与无机嵌段共价键合;有机嵌段是聚环氧乙烷（PEO）。 采用氮氧自由基聚合法，以官能化的PEO为大分子引发剂，合成了杂化嵌段共聚物（PEO-POSS）。 早期的研究结果表明，纯PEO-POSS嵌段共聚物的相行为与预期的一样：升高温度导致有序到无序的转变。与此相反，含盐的PEO-POSS混合物表现出无序到有序的转变，随着温度的升高。 嵌段比，链长和POSS功能的影响将通过去偏振光散射，X射线散射和电子断层扫描的组合进行研究。 测量将在宽范围的嵌段共聚物组合物，盐浓度和退火条件下进行。 将通过交流阻抗谱测量形态对离子传输的影响。 所提出的工作的智力价值将是在一个新兴的混合纳米结构聚合物，包括完全有机聚合物和聚合物与共价键合的无机纳米粒子的热力学相互作用和离子输运的研究;这些属性的定量理解在很大程度上限于所有有机链。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL DESCRIPTION:Life is increasingly intertwined with electrochemical energy storage, mainly in the form of lithium batteries. They are integral to cellphones, laptops, scooters, electric vehicles, homes, solar installations, and even airplanes. But these basic devices have potential safety hazards because they carry within a highly flammable liquid that has led to explosions and fires. Building an intrinsically safe rechargeable lithium battery remains an unmet challenge, particularly in the development of a nonflammable electrolyte (the material that allows the flow of electrical charge in the battery) to replace the flammable organic liquid electrolyte in current lithium batteries. Polymer electrolytes offer a promising alternative to the flammable liquid. All previous studies have considered polymers made from organic building blocks. The proposed work begins with a novel approach: the synthesis of a hybrid polymer that comprises both organic and inorganic building blocks. The polymer spontaneously forms 10-nanometer-wide alternating organic and inorganic layers (a human hair is 100,000 nanometers wide). This material had very low flammability. The organic layers conduct the lithium ions while the inorganic layers provide mechanical rigidity to the polymer electrolyte, a property that is necessary to keep the two battery electrodes from touching and short-circuiting the battery. The planned work examines the relationship between layer formation and lithium-ion motion through the composite electrolyte. The PIs collaborating on this project will also be working on diversity-related initiatives on the UC Berkeley campus, on organizing public lectures on scientific subjects aimed at high school students in Brooklyn, and on providing multidisciplinary training to undergraduate and graduate students at their institutions.TECHNICAL DESCRIPTION:The proposed work focuses on mixtures of hybrid organic-inorganic block copolymers and a lithium salt. Functionalized polyhedral oligomeric silsesquioxane (POSS) particles are covalently bonded to the inorganic block; the organic block is polyethylene oxide (PEO). The hybrid block copolymers (PEO-POSS) will be synthesized using nitroxide-mediated radical polymerization with functionalized PEO as the macro-initiator. Early results indicate that the phase behavior of pure PEO-POSS block copolymers is as expected: increasing temperature leads to an order-to-disorder transition. In contrast, salt-containing PEO-POSS mixtures exhibit a disorder-to-order transition with increasing temperature. The effect of block ratio, chain length, and POSS functionality will be studied by a combination of depolarized light scattering, X-ray scattering, and electron tomography. Measurements will be made over a wide range of block copolymer compositions, salt concentration, and annealing conditions. The effect of morphology on ion transport will be measured by ac impedance spectroscopy. The intellectual merit of the proposed work will be the study of the thermodynamic interactions and ion transport in an emerging class of hybrid nanostructured polymers comprising fully organic polymers and polymers with covalently-bonded inorganic nanoparticles; the present quantitative understanding of these properties is largely restricted to all-organic chains. .This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.