烷基链长度对酰亚胺基负极材料的性能影响

The effect of alkyl chain length on the performance of imides as anodes for lithium-ion batteries

近年来,有机电极材料由于其质轻、成本低、来源丰富,更重要的是可以通过分子机构设计来调控电极材料的氧化还原电位和可逆的锂离子嵌入和脱出反应,受到研究者们的广泛关注。将带有电化学活性位点的小分子有机羰基化合物通过聚合形成稳定大分子,可以避免溶解问题并且具有氧化还原反应活性,从而提高电极材料循环性能。从分子结构设计出发,以3,3′,4,4′-二苯酮四酸二酐(BTDA)为酸酐,分别与三种不同烷基链长度的脂肪族二胺乙二胺、1,6-己二胺和1,8-辛二胺合成得到带有不同数量—CH 2—的BTDA基酰亚胺材料,研究了烷基链长度对BTDA基酰亚胺材料作为锂离子负极材料的电化学性能的影响。通过较短烷基链长度的二胺得到的酰亚胺材料具有更高的比容量,并且具有更稳定的循环性能。

Thanks to their many outstanding merits such as lightweight,low cost,flexibility,abundant resources and precursors,electroactive organic materials have received great attention in recent years.More importantly,rich organic materials can be designed on the molecular level through organic chemistry theoretical basis and organic synthesis techniques,which can also tune the redox potential and redox reactions.Synthesizing stable macromolecule through polymerization of small organic carbonyl compounds with electrochemically active sites can be an effective approach to avoid dissolution problem and improve cycling performance.From the perspective of molecular structure design,linear-chain aliphatic amine homologues with different length of alkyl chains,including ethylene diamine,1,6-hexanediamine and 1,8-diaminooctane,were used as connection segments of the dianhydride with conjugated carbonyl groups.The effect of alkyl chain length on BTDA-based aromatic imides as lithium-ion anode materials has been studied.Imides synthesized by diamines with shorter alkyl chain possesses higher specific capacity and more stable cycling performance.