Department of Polymer Engineering and ‡Department of Polymer Science, University of Akron , Akron, Ohio 44325, United States.
ACS Appl Mater Interfaces. 2014 Dec 10;6(23):21011-8. doi: 10.1021/am5058037. Epub 2014 Nov 24.
Polymerization-induced phase separation of nanoparticle-filled solution is demonstrated as a simple approach to control the structure of porous composites. These composites are subsequently demonstrated as the active component for sodium ion battery anode. To synthesize the composites, we dissolved/dispersed titanium oxide (anatase) nanoparticles (for sodium insertion) and poly(hydroxybutyl methacrylate) (PHBMA, porogen) in furfuryl alcohol (carbon precursor) containing a photoacid generator (PAG). UV exposure converts the PAG to a strong acid that catalyzes the furfuryl alcohol polymerization. This polymerization simultaneously decreases the miscibility of the PHBMA and reduces the mobility in the mixture to kinetically trap the phase separation. Carbonization of this polymer composite yields a porous nanocomposite. This nanocomposite exhibits nearly 3-fold greater gravimetric capacity in Na-ion batteries than the same titanium oxide nanoparticles that have been coated with carbon. This improved performance is attributed to the morphology as the carbon content in the composite is five times that of the coated nanoparticles. The porous composite materials exhibit stable cyclic performance. Moreover, the battery performance using materials from this polymerization-induced phase separation method is reproducible (capacity within 10% batch-to-batch). This simple fabrication methodology may be extendable to other systems and provides a facile route to generate reproducible hierarchical porous morphology that can be beneficial in energy storage applications.
聚合物诱导的纳米颗粒填充溶液相分离被证明是一种控制多孔复合材料结构的简单方法。这些复合材料随后被证明是钠离子电池阳极的活性成分。为了合成复合材料，我们将氧化钛（锐钛矿）纳米颗粒（用于钠离子插入）和聚（羟丁基甲基丙烯酸酯）（PHBMA，致孔剂）溶解/分散在呋喃甲醇（碳前体）中，其中含有光酸产生剂（PAG）。UV 照射将 PAG 转化为强酸，催化呋喃甲醇聚合。这种聚合同时降低了 PHBMA 的混溶性，并降低了混合物中的迁移率，从而在动力学上捕获了相分离。这种聚合物复合材料的碳化产生了多孔纳米复合材料。与经过碳涂层的相同氧化钛纳米颗粒相比，这种纳米复合材料在钠离子电池中的重量比容量提高了近 3 倍。这种改进的性能归因于形态，因为复合材料中的碳含量是涂层纳米颗粒的五倍。多孔复合材料表现出稳定的循环性能。此外，使用这种聚合诱导相分离方法制备的材料的电池性能具有可重现性（批次间容量差异在 10%以内）。这种简单的制造方法可能适用于其他系统，并提供了一种简便的方法来产生可重复的分级多孔形态，这在能量存储应用中可能是有益的。
