Tailoring interlayer spacing in MXene cathodes to boost the desalination performance of hybrid capacitive deionization systems  

作　　者：Bei Li Kang Sun Wenyu Xu Xiaojing Liu Ao Wang Steven Boles Bin Xu Haibo Hu Dongrui Yao 

机构地区：[1]Jiangsu Engineering Research Center of Aquatic Plant Resources and Water Environment Remediation,Institute of Botany,Jiangsu Province and Chinese Academy of Sciences,Nanjing 210014,China [2]Institute of Chemical Industry of Forest Products,Chinese Academy of Forestry,Nanjing 210042,China [3]School of Materials Science and Engineering,Anhui University,Hefei 230601,China [4]Department of Energy and Process Engineering,Norwegian University of Science and Technology,Trondheim,Norway [5]Nanjing Institute of Environmental Sciences,Ministry of Ecology and Environment of the People's Republic of China,Nanjing 210042,China

出　　处：《Nano Research》2023年第5期6039-6047,共9页纳米研究（英文版）

基　　金：the National Natural Science Foundation of China(Nos.52100009,51871001,and 51808251);the China Postdoctoral Science Foundation(No.2021M691337);Excellent Youth Fund of Anhui Province(No.2108085Y17);Hundred-Talent Program of Anhui Province;the Innovative team project of Nanjing Institute of Environmental Sciences,MEE.

摘　　要：Capacitive deionization(CDI)is a promising technology to satisfy the global need for fresh water,since it can be both economical and sustainable.While two-dimensional transition metal carbides/nitrides(MXenes)exhibit great characteristics for use as CDI electrode materials,their tightly spaced layered structure renders intercalation inefficiency.In this study,the interlayer distance of MXenes is precisely modulated by inserting different quantity of one-dimensional bacterial fibers(BC),forming freestanding MXene/BC composite electrodes.Among the studied samples,MXene/BC-33%electrode with the interlayer spacing of 15.2Åcan achieve an optimized tradeoff among various desalination performance metrics and indicators.The salt adsorption capacity(SAC),the average salt adsorption rate(ASAR),the energy normalized adsorbed salt(ENAS),and the thermodynamic energy efficiency(TEE)of the MXene/BC-33%electrode are improved by 24%,46%,13%,and 66%respectively compared with those of pure MXene electrode.While the insertion of BC improves the ion diffusion pathways and facilitates the intercalation kinetics,the desalination performance decreases when the insertion amount of BC exceeds 40%.This is attributed to the overlarge resistance of the composite and the resulting increased energy consumption.This study reveals the desalination performance tradeoffs of MXene-based electrodes with different interlayer distances and also sheds light on the fundamental ion storage mechanisms of intercalation materials in a CDI desalination system.

关 键 词：capacitive deionization MXene intercalation materials hybrid capacitive deionization cation intercalation 

分 类 号：O64[理学—物理化学]