Zhou Shengyang, Kong Xueying, Zheng Bing, Huo Fengwei, Strømme Maria, Xu Chao
Nanotechnology and Functional Materials, Department of Engineering Sciences, Ångström Laboratory , Uppsala University , 751 21 Uppsala , Sweden.
Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) , Nanjing Tech University (NanjingTech) , 211816 Nanjing , China.
ACS Nano. 2019 Aug 27;13(8):9578-9586. doi: 10.1021/acsnano.9b04670. Epub 2019 Jul 15.
Conductive metal-organic frameworks (c-MOFs) show great potential in electrochemical energy storage thanks to their high electrical conductivity and highly accessible surface areas. However, there are significant challenges in processing c-MOFs for practical applications. Here, we report on the fabrication of c-MOF nanolayers on cellulose nanofibers (CNFs) with formation of nanofibrillar CNF@c-MOF by interfacial synthesis, in which CNFs serve as substrates for growth of c-MOF nanolayers. The obtained hybrid nanofibers of CNF@c-MOF can be easily assembled into freestanding nanopapers, demonstrating high electrical conductivity of up to 100 S cm, hierarchical micromesoporosity, and excellent mechanical properties. Given these advantages, the nanopapers are tested as electrodes in a flexible and foldable supercapacitor. The high conductivity and hierarchical porous structure of the electrodes endow fast charge transfer and efficient electrolyte transport, respectively. Furthermore, the assembled supercapacitor shows extremely high cycle stability with capacitance retentions of >99% after 10000 continuous charge-discharge cycles. This work provides a pathway to develop flexible energy storage devices based on sustainable cellulose and MOFs.
导电金属有机框架（c-MOFs）因其高电导率和高可及表面积在电化学储能方面展现出巨大潜力。然而，将c-MOFs加工用于实际应用存在重大挑战。在此，我们报道了通过界面合成在纤维素纳米纤维（CNFs）上制备c-MOF纳米层，并形成纳米纤维状的CNF@c-MOF，其中CNFs作为c-MOF纳米层生长的基底。所获得的CNF@c-MOF杂化纳米纤维可轻松组装成独立的纳米纸，展现出高达100 S cm的高电导率、分级微介孔结构以及优异的机械性能。鉴于这些优点，该纳米纸被测试用作柔性可折叠超级电容器的电极。电极的高电导率和分级多孔结构分别赋予了快速电荷转移和高效电解质传输能力。此外，组装的超级电容器显示出极高的循环稳定性，在10000次连续充放电循环后电容保持率>99%。这项工作为基于可持续纤维素和MOFs开发柔性储能装置提供了一条途径。
