张瑾, 黄莉雅, 蔡锋石, 罗志强, 袁志好. 2,6-二氨基蒽醌/还原氧化石墨烯复合材料的制备及在锂有机电池的应用[J]. 工程科学学报, 2023, 45(7): 1165-1174. DOI: 10.13374/j.issn2095-9389.2022.03.22.003
引用本文: 张瑾, 黄莉雅, 蔡锋石, 罗志强, 袁志好. 2,6-二氨基蒽醌/还原氧化石墨烯复合材料的制备及在锂有机电池的应用[J]. 工程科学学报, 2023, 45(7): 1165-1174. DOI: 10.13374/j.issn2095-9389.2022.03.22.003
ZHANG Jin, HUANG Li-ya, CAI Feng-shi, LUO Zhi-qiang, YUAN Zhi-hao. Preparation of 2,6-diaminoanthraquinone/reduced graphene oxide-based composites as cathode materials for organic lithium batteries[J]. Chinese Journal of Engineering, 2023, 45(7): 1165-1174. DOI: 10.13374/j.issn2095-9389.2022.03.22.003
Citation: ZHANG Jin, HUANG Li-ya, CAI Feng-shi, LUO Zhi-qiang, YUAN Zhi-hao. Preparation of 2,6-diaminoanthraquinone/reduced graphene oxide-based composites as cathode materials for organic lithium batteries[J]. Chinese Journal of Engineering, 2023, 45(7): 1165-1174. DOI: 10.13374/j.issn2095-9389.2022.03.22.003

2,6-二氨基蒽醌/还原氧化石墨烯复合材料的制备及在锂有机电池的应用

Preparation of 2,6-diaminoanthraquinone/reduced graphene oxide-based composites as cathode materials for organic lithium batteries

  • 摘要: 采用水热合成法和冷冻干燥技术制备了2,6-二氨基蒽醌(2,6-AAQ)/rGO复合材料,通过氨基(—NH2)与羧基(—COOH)形成肽键(—CO—NH—)共价键,使其在电解液中的溶解问题从本质上得到了解决。SEM和EDS Mapping表明,2,6-AAQ/rGO-3复合材料中的2,6-AAQ呈现出高度的棒状结构,并且被石墨烯包裹得更紧密。这种独特的结构提高了2,6-AAQ在锂化过程中的电子导电性,可有效减少2,6-AAQ的聚集,利于电解质的浸润。XPS、XRD、FTIR和Raman结果表明,2,6-AAQ和rGO之间发生了水热辅助化学键合,形成了rGO包裹2,6-AAQ的结构。此外,非原位FTIR表征结果验证了2,6-AAQ/rGO-3具有良好的储锂性能,羰基(C=O)为反应位点。同时,紫外-可见光谱测试清楚表明,与2,6-AAQ相比,通过肽键连接的2,6-AAQ/rGO-3的溶解度显著降低,表明电化学性能大大提高。其中2,6-AAQ/rGO-3作为锂离子电池正极时,在100 mA·g−1电流下,首圈放电容量高达212.2 mA·h·g−1, 在500 mA·g−1电流下循环100周后放电容量仍为184 mA·h·g−1,展现出了优异的循环稳定性和高倍率性能。2,6-AAQ/rGO出色的电化学性能得益于石墨烯的碳骨架对2,6-AAQ的锚定,该结构不仅可以防止2,6-AAQ溶解,还可以为其提供导电网络,进一步提高电子传导速率。

     

    Abstract: Organic carbonyl compounds have received great attention as electrode materials because of their fast reduction–oxidation kinetics, environment friendliness, and high theoretical capacity. Especially, the small molecular quinones, such as anthraquinone (AQ), can possess high theoretical (257 mA·h·g−1) and a discharge–charge voltage of 2.2–2.3 V, implying that it has the potential of up to 565 W·h·kg−1 energy density. However, it suffers from high solubility in organic electrolytes and low conductivity, leading to rapid capacity fading and inferior rate performance. Herein, we report 2,6-diaminoanthraquinone (2,6-AAQ) uniform self-assembly into a three-dimensional (3D) porous structure graphene foam, which was successfully fabricated through a gentle hydrothermal synthesis reaction with simultaneous in situ condensation of 2,6-AAQ on the reduced graphene surface, as a high-performance cathode for Lithium-organic batteries. Benefiting from the formation of a covalent bond (—CO—NH—) between the amino group (—NH2) of 2,6-AAQ and the carboxyl group (—COOH) of oxidized graphene, the molecular structure of AQ is uniformly anchored into a 3D graphene foam architecture. The strategy simultaneously solved the high dissolution and low conductivity of AQ. The as-obtained hybrid composites were characterized by various techniques. SEM and EDS mapping images demonstrated that the 2,6-AAQ within the hybrid architecture was not only uniformly anchored on the surface but also tightly wrapped in the interior of graphene foam. This unique architectural structure can improve the electronic conductivity of 2,6-AAQ in the lithiation process and effectively inhibit the dissolution of 2,6-AAQ in electrolytes, which is beneficial to hoist the electrochemical performance of the composite materials. XPS, XRD, FTIR, and Raman results indicated that hydrothermally assisted chemical bonding occurred between 2,6-AAQ and rGO, significantly facilitating the mass electron transformation and ion diffusion from graphene substrate to 2,6-AAQ for the fast reduction–oxidation reaction. Combined with the above results, UV–Vis spectroscopy tests also further disclosed that the 2,6-AAQ and rGO linked by covalent bonds significantly decrease solubility compared with 2,6-AAQ, indicating the greatly increased cycling stability of the hybrid material. Additionally, ex situ FTIR characterization results verified that the composite cathode material with two carbonyls (C=O) active sites has good lithium storage performance. By optimizing the 2,6-AAQ concentration, the 25% 2,6-AAQ in the as-prepared composite was used as the high-performance cathode for the lithium-ion battery. The composite material can display a high initial discharge capacity of 212.2 mA·h·g−1 at 100 mA·g−1 (based on the 2,6-AAQ mass) and a reversible capacity of 184 mA·h·g−1 with a capacity retention of 86.7% after 100 cycles at 500 mA·g−1 current density. This excellent electrochemical performance is attributed to fast lithium-ion diffusion and electric transport between the 2,6-AAQ and the 3D porous structure hybrid architecture, which also proposes a facile strategy for the immobilization of the small molecular quinones to construct advanced organic lithium batteries.

     

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