Xiong Jianbo, Li Qing, Li Kaihui, Guo Xue, Zhong Ming, Wang Ruoyu, Chen Yao, Tan Xiaojuan, Na Bing, Tong Xiaolan
State Key Laboratory of Nuclear Resources and Environment, School of Chemistry and Materials, East China University of Technology, Nanchang 330013, China.
State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
J Colloid Interface Sci. 2025 Mar;681:182-191. doi: 10.1016/j.jcis.2024.11.177. Epub 2024 Nov 26.
Two-dimensional metal-organic frameworks (2D MOFs) have been considered to be one type of potential cathodes for lithium storage due to their regular channels and devisable redox-active sites. However, the relatively low electrical conductivity and weak long-term cyclability hindered their development. Herein, we report an optimized bimetallic conductive 2D MOF (CoNi(HHTP)) for enhanced lithium-ion storage. Specifically, the optimal 2D MOF electrode demonstrates a reversible capacity of 615.2 mAh/g at 0.2 A/g and the specific energy density up to 826 Wh Kg after 100 cycles. Moreover, a heterostructure (CoNi(HHTP)@MXene) was constructed by stacking CoNi(HHTP) MOF on the 2D TiC MXene nanosheets to improve the rate performance and cycling stability. The heterostructure electrode kept 74.1 % of the initial capacity with nearly 100 % coulombic efficiency even at 2000 cycles. Ex situ characterizations and density functional theory calculations were carried out to reveal the redox mechanism of the 2D conductive MOF. Electronic states study unveils that the quinoid oxygens and the metal centers are responsible for the redox reaction during lithiation/delithiation process, the composited 2D MXene can promote the electron transfer. The development of bimetallic mixed conductive 2D MOF @ 2D MXene heterogeneity offers valuable insights into the design of electrode materials for lithium storage.
二维金属有机框架（2D MOF）因其规则的通道和可设计的氧化还原活性位点而被认为是一种潜在的锂存储阴极材料。然而，相对较低的电导率和较弱的长期循环稳定性阻碍了它们的发展。在此，我们报道了一种优化的双金属导电二维MOF（CoNi(HHTP)）用于增强锂离子存储。具体而言，优化后的二维MOF电极在0.2 A/g电流密度下展现出615.2 mAh/g的可逆容量，经过100次循环后比能量密度高达826 Wh Kg。此外，通过将CoNi(HHTP) MOF堆叠在二维TiC MXene纳米片上构建了异质结构（CoNi(HHTP)@MXene），以提高倍率性能和循环稳定性。即使在2000次循环时，该异质结构电极仍保持初始容量的74.1%，库仑效率接近100%。通过非原位表征和密度泛函理论计算揭示二维导电MOF的氧化还原机制。电子态研究表明，醌型氧和金属中心在锂化/脱锂过程中负责氧化还原反应，复合的二维MXene可以促进电子转移。双金属混合导电二维MOF@二维MXene异质结构的发展为锂存储电极材料的设计提供了有价值的见解。
