摘要
Conventional carbon materials cannot combine high density and high porosity,which are required in many applications,typically for energy storage under a limited space.A novel highly dense yet porous carbon has previously been produced from a three-dimensional(3D)reduced graphene oxide(r-GO)hydrogel by evaporation-induced drying.Here the mechanism of such a network shrinkage in r-GO hydrogel is specifically illustrated by the use of water and 1,4-dioxane,which have a sole difference in surface tension.As a result,the surface tension of the evaporating solvent determines the capillary forces in the nanochannels,which causes shrinkage of the r-GO network.More promisingly,the selection of a solvent with a known surface tension can precisely tune the microstructure associated with the density and porosity of the resulting porous carbon,rendering the porous carbon materials great potential in practical devices with high volumetric performance.
以两亲性氧化石墨烯为结构单元,可控组装构建三维网络石墨烯水凝胶,通过溶剂蒸发驱动网络致密化,获得高密多孔碳,解决了传统多孔碳电极体积容量低的应用瓶颈.本文旨在探究氧化石墨烯水凝胶致密化机理,阐明了毛细作用力是使溶剂脱出并引发石墨烯网络收缩的驱动力.溶剂表面张力决定毛细作用力,因此通过调节溶剂表面张力或采用不同表面张力的溶剂,可以实现"孔"与"密"的"收放自如"调控,从而得到不同密度和孔隙率的高密多孔碳,实现高密和多孔连续精确调控.氧化石墨烯水凝胶的毛细收缩也为纳米材料致密化提供了方法论支持.
作者
Changsheng Qi
Chong Luo
Ying Tao
Wei Lv
Chen Zhang
Yaqian Deng
Huan Li
Junwei Han
Guowei Ling
Quan-Hong Yang
戚昌盛;罗冲;陶莹;吕伟;张辰;邓亚茜;李欢;韩俊伟;凌国维;杨全红(Nanoyang Group,State Key Laboratory of Chemical Engineering,School of Chemical Engineering and Technology,Collaborative Innovation Center of Chemical Science and Engineering(Tianjin),Tianjin University,Tianjin 300350,China;Shenzhen Geim Graphene Center and Engineering Laboratory for Functionalized Carbon Materials,Graduate School at Shenzhen,Tsinghua University,Shenzhen 518055,China;School of Marine Science and Technology,Tianjin University,Tianjin 300350,China;Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Binhai New City,Fuzhou 350207,China)
基金
This work was supported by the National Natural Science Fund for the Distinguished Young Scholars,China(51525204)
the National Natural Science Foundation of China(51702229 and 51872195)
the CAS Key Laboratory of Carbon Materials(KLCM KFJJ1704).
