GOALI: Self-Assembled Multivalent Lithium Salts for Solid Polymer Electrolytes

GOALI：用于固体聚合物电解质的自组装多价锂盐

• 批准号: 1207221
• 负责人: Stephanie Wunder
• 金额: $ 37.33万
• 依托单位: Temple University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1207221&HistoricalAwards=false
• 关键词: GOALI; Self; Assembled; Multivalent; Lithium

TECHNICAL SUMMARY:This GOALI project is a collaboration between Temple University, Hybrid Plastics, and MaxPower, Inc., and addresses the fundamental question of whether it is possible, using an understanding of the self-assembly of nanomaterials and lithium ion diffusion in polymers, to design solid polymer electrolytes (SPEs) that have both high room-temperature conductivity ( 1 x 10-3 S/cm) and lithium ion transference numbers, tLi+, that approach 1. The SPEs so formed will have the advantages of liquid electrolytes without the accompanying safety problems of volatility, flammability and dendrite formation. Multi-ionic lithium salts will be synthesized from polyoctahedral silsesquioxane (POSS) nanoparticles and combined with polyethylene oxide (PEO), since preliminary data indicate that these SPEs exhibit improved lithium ion transport properties. The polyoctahedral silsesquioxanes are Janus-like nanoparticles, with hydrophobic phenyl groups at one end and ionic groups based on -Si-O-BF3- Li+ at the other end. In the morphology that forms, the phenyl groups cluster and the -Si-O-BF3- groups orient towards the PEO phase. The electron withdrawing POSS cage and BF3 groups delocalize the negative charge on the anion so that the dissociated Li+ can be solvated by the surrounding PEO matrix. The PEO is completely amorphous, so that the resulting solid structure is not the result of PEO crystallinity but instead it is proposed to be the result of phenyl crystallites and crosslinks formed from -Si-O-BF3 anion--- Li+---O-H2CH2 bridges that connect the phenyl clusters and PEO chains. Enhanced conductivity may be the result of this morphology, in which Li+ ions are loosely coordinated to several -Si-O-BF3 anions, and may migrate along the interfacial regions with a lower activation energy. Preliminary data show ionic conductivities of 3 x 10-4 S/cm, close to the target value of 1 x 10-3 S/cm, with tli+ = 0.6. Better designed multi-ionic lithium salts in which the Li+/phenyl group ratio is increased will be investigated. The purpose is to minimize the amount of non-conductive phase needed to maintain a solid without PEO crystallinity and to maximize the amount of low Tg conductive phase with solvated Li+ ions. Morphology, mechanical and electrochemical properties will be correlated to elucidate the factors that contribute to enhanced conductivity. This project is supported by the NSF Solid State and Materials Chemistry Program.NON-TECHNICAL SUMMARY:The potential impact of the proposed research is improved solid polymer electrolytes that would enhance the performance of lithium/lithium ion batteries used in large electrical energy storage applications such as electric vehicles/hybrid electric vehicles or matching the output of fluctuating power sources including wind and solar with fluctuating demand. Solid polymer electrolytes are intrinsically safer than the volatile liquid electrolytes currently used in small lithium ion batteries for portable devices. The research will focus on the development of new materials which have ionic conductivities comparable to those of current liquid electrolytes, but are safer and have better performance overall. Material synthesis will be performed in collaboration with Hybrid Plastics, Inc., a company with the expertise and scale-up facilities necessary for the project. Long-term battery testing for complete evaluation of the new solid polymer electrolyte materials that are developed will be accomplished through collaboration with MaxPower, Inc, a lithium battery manufacturer. Undergraduate/graduate students will participate in interdisciplinary research in polymer-, organic- and electro-chemistry both in academic and industrial environments.

技术概述：这个项目是天普大学、混合塑料公司和MaxPower公司的合作项目，解决的根本问题是，利用纳米材料的自组装和锂离子在聚合物中的扩散，是否有可能设计具有高室温电导率(1 x 10-3 S/厘米)和锂离子迁移数TLi+的固体聚合物电解质(SPE)。这样形成的SPE将具有液体电解质的优势，而不会伴随着挥发性、可燃性和树枝晶形成等安全问题。多离子锂盐将由倍半硅氧烷(POSS)纳米粒子合成，并与聚氧乙烷(PEO)结合，因为初步数据表明，这些SPE具有更好的锂离子传输性能。多八面体倍半硅氧烷为Janus状纳米粒子，其一端带有疏水苯基，另一端带有基于-Si-O-BF3-Li+的离子基团。在所形成的形貌中，苯基团簇和-Si-O-BF3-基团朝向PEO相。吸电子的POSS笼和BF3基团离域了阴离子上的负电荷，从而使解离的Li+可以被周围的PEO基质溶解。PEO是完全无定形的，因此得到的固体结构不是PEO结晶度的结果，而是-Si-O-BF3阴离子-Li+--O-H_2CH2桥连接苯基簇合物和PEO链形成的苯基微晶和交联键的结果。电导率的提高可能是这种形态的结果，其中Li+离子与几个-Si-O-BF3阴离子松散配位，并可能沿着活化能较低的界面区迁移。初步数据显示，离子电导率为3×10-4 S/厘米，接近目标值1×10-3 S/厘米，Tli+=0.6。将研究设计更好的多离子锂盐，其中Li+/苯基的比例增加。其目的是最大限度地减少保持没有PEO结晶度的固体所需的非导电相的数量，并最大限度地增加含有溶剂化Li+离子的低Tg导电相的数量。形态、机械和电化学性质将相互关联，以阐明有助于提高导电性的因素。该项目得到了NSF固态和材料化学计划的支持。非技术摘要：拟议研究的潜在影响是改进的固体聚合物电解液，它将增强用于大型电能储存应用(如电动汽车/混合动力汽车)的锂/锂离子电池的性能，或使风能和太阳能等波动电源的输出与不断变化的需求相匹配。固体聚合物电解质本质上比目前用于便携式设备的小型锂离子电池中的挥发性液体电解质更安全。这项研究将专注于开发新材料，这些材料的离子导电率与目前的液体电解质相当，但更安全，总体性能更好。材料合成将与混合塑料公司合作进行，该公司拥有该项目所需的专业知识和放大设施。为对开发的新型固体聚合物电解质材料进行全面评估而进行的长期电池测试将通过与锂电池制造商MaxPower，Inc.合作完成。本科生/研究生将在学术和工业环境中参与聚合物、有机和电化学的跨学科研究。