Forsyth Maria, Porcarelli Luca, Wang Xiaoen, Goujon Nicolas, Mecerreyes David
Institute for Frontier Materials , Deakin University , Geelong , VIC 3217 , Australia.
Polymat, Institute for Polymer Materials , University of the Basque Country UPV/EHU , Joxe Mari Korta Center, Avda. Tolosa 72 , 20018 Donostia-San Sebastian , Spain.
Acc Chem Res. 2019 Mar 19;52(3):686-694. doi: 10.1021/acs.accounts.8b00566. Epub 2019 Feb 25.
Electrolytes based on organic solvents used in current Li-ion batteries are not compatible with the next-generation energy storage technologies including those based on Li metal. Thus, there has been an increase in research activities investigating solid-state electrolytes, ionic liquids (ILs), polymers, and combinations of these. This Account will discuss some of the work from our teams in these areas. Similarly, other metal-based technologies including Na, Mg, Zn, and Al, for example, are being considered as alternatives to Li-based energy storage. However, the materials research required to effectively enable these alkali metal based energy storage applications is still in its relative infancy. Once again, electrolytes play a significant role in enabling these devices, and research has for the most part progressed along similar lines to that in advanced lithium technologies. Some of our recent contributions in these areas will also be discussed, along with our perspective on future directions in this field. For example, one approach has been to develop single-ion conductors, where the anion is tethered to the polymer backbone, and the dominant charge conductor is the lithium or sodium countercation. Typically, these present with low conductivity, whereas by using a copolymer approach or incorporating bulky quaternary ammonium co-cations, the effective charge separation is increased thus leading to higher conductivities and greater mobility of the alkali metal cation. This has been demonstrated both experimentally and via computer simulations. Further enhancements in ion transport may be possible in the future by designing and tethering more weakly associating anions to the polymer backbone. The second approach considers ion gels or composite polymer electrolytes where a polymerized ionic liquid is the matrix that provides both mechanical robustness and ion conducting pathways. The block copolymer approach is also demonstrated, in this case, to simultaneously provide mechanical properties and high ionic conductivity when used in combination with ionic-liquid electrolytes. The ultimate electrolyte material that will enable all high-performance solid-state batteries will have ion transport decoupled from the mechanical properties. While inorganic conductors can achieve this, their rigid, brittle nature creates difficulties. On the other hand, ionic polymers and their composites provide a rich area of chemistry to design and tune high ionic conductivity together with ideal mechanical properties.
当前锂离子电池中使用的基于有机溶剂的电解质与包括基于锂金属的下一代储能技术不兼容。因此，对固态电解质、离子液体（ILs）、聚合物以及它们的组合进行研究的活动有所增加。本综述将讨论我们团队在这些领域的一些工作。同样，其他基于金属的技术，例如钠、镁、锌和铝，正被视为锂基储能的替代品。然而，有效实现这些基于碱金属的储能应用所需的材料研究仍处于相对初期阶段。电解质在使这些器件成为可能方面再次发挥了重要作用，并且研究在很大程度上沿着与先进锂技术相似的路线进行。还将讨论我们最近在这些领域的一些贡献，以及我们对该领域未来方向的看法。例如，一种方法是开发单离子导体，其中阴离子连接到聚合物主链上，主要的电荷导体是锂或钠反离子。通常，这些单离子导体的电导率较低，而通过使用共聚物方法或引入庞大的季铵共阳离子，有效电荷分离增加，从而导致更高的电导率和碱金属阳离子更大的迁移率。这已通过实验和计算机模拟得到证明。未来通过设计并将更弱缔合的阴离子连接到聚合物主链上，离子传输可能会进一步增强。第二种方法考虑离子凝胶或复合聚合物电解质，其中聚合离子液体是提供机械强度和离子传导途径的基质。在这种情况下，还展示了嵌段共聚物方法，当与离子液体电解质结合使用时，可同时提供机械性能和高离子电导率。能够实现所有高性能固态电池的最终电解质材料将使离子传输与机械性能解耦。虽然无机导体可以做到这一点，但其刚性、脆性的性质带来了困难。另一方面，离子聚合物及其复合材料提供了丰富的化学领域，可用于设计和调节高离子电导率以及理想的机械性能。
