Graphene acid/MXenes heterostructures for lithium- and sodium-ion batteries. (Acronym GRAPhMAX)

用于锂和钠离子电池的石墨烯酸/MXenes异质结构。

• 批准号: 471730733
• 负责人: Professor Dr. Volker Presser
• 金额: --
• 依托单位: Leibniz-Institut für Neue Materialien gGmbH (INM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/471730733?language=en
• 关键词: Graphene; acid; MXenes; heterostructures; lithium

The aim of GRAPhMAX is the development of a high-performance organic anode for Li and Na-ion batteries, exploiting graphene-acid as the active electrode and explore its operation as a free-standing film at high areal masses, by developing covalent and non-covalent heterostructures with MXenes. MXenes and graphene acid both can, when combined carefully, greatly benefit from mutually synergetic properties.MXenes’ properties are strongly influenced by their surface termination and, in theory, may provide a metal-like conductivity. As electrodes, they can reach a conductivity of 15,100 S/cm, while graphene acid only reaches 0.25 S/cm. They have also demonstrated their potential for high areal mass electrodes. However, capacity-wise, MXenes show low values; Ti2C, for example, stands below 200 mAh/g at 0.03 A/g. Ti3C2, the most widely studied MXene, shows capacities around 100 mAh/g at 0.03 A/g. Only after strict selection of monolayers for electrode preparation, the capacity may reach 410 mAh/g at 0.41 A/g, due to layer expansion, larger surface area, and maximum exposure of MXene’s redox-active centers to the electrolyte ions. On the contrary, the previously reported capacities for graphene acid were obtained without any layer-thickness selection during the whole synthetic procedure, but free-standing films and thickness-persistent properties have been so far unattainable. On this basis, we hypothesize that graphene acid /MXene heterostructures could benefit from their complementary assets, leading to profound synergism: the high conductivity of MXenes and their film-forming properties may enhance charge transfer and film stability in their heterostructures with graphene acid, enabling free-standing high-performance graphene acid electrodes with increased areal mass. To achieve this objective, an efficient hybridization methodology must be developed involving covalent and/or non-covalent approaches for preparing graphene acid/MXene free-standing heterostructures with optimum mass ratio with respect to the final required properties screened by structural characterization and electrochemical testing.

GRAPhMAX 的目标是开发用于锂离子和钠离子电池的高性能有机阳极，利用石墨烯酸作为活性电极，并通过开发具有 MXene 的共价和非共价异质结构来探索其在大面积质量下作为独立薄膜的操作。当仔细组合时，MXene 和石墨烯酸都可以极大地受益于相互协同的特性。MXene 的特性受到其表面终止的强烈影响，理论上可以提供类似金属的导电性。作为电极，它们的电导率可以达到15,100 S/cm，而石墨烯酸只能达到0.25 S/cm。他们还展示了大面积电极的潜力。然而，就容量而言，MXene 的价值较低；例如，Ti2C 在 0.03 A/g 电流下的容量低于 200 mAh/g。 Ti3C2 是研究最广泛的 MXene，在 0.03 A/g 电流下的容量约为 100 mAh/g。只有在严格选择单层电极制备后，由于层膨胀、更大的表面积以及 MXene 氧化还原活性中心最大程度地暴露于电解质离子，容量在 0.41 A/g 下才可能达到 410 mAh/g。相反，之前报道的石墨烯酸容量是在整个合成过程中没有任何层厚度选择的情况下获得的，但迄今为止仍无法实现自立式薄膜和厚度持久特性。在此基础上，我们假设石墨烯酸/MXene异质结构可以受益于它们的互补性，从而产生深刻的协同作用：MXene的高电导率及其成膜特性可以增强石墨烯酸异质结构中的电荷转移和薄膜稳定性，从而实现面积质量增加的独立式高性能石墨烯酸电极。为了实现这一目标，必须开发一种有效的杂交方法，涉及共价和/或非共价方法，用于制备石墨烯酸/MXene独立异质结构，相对于通过结构表征和电化学测试筛选的最终所需性能，具有最佳质量比。