V_(2)CF_(x)MXene衍生2D V_(2)O_(3)@介孔碳纳米片的制备及其电容脱盐特性  

Preparation of 2D V_(2)O_(3)@Pourous Carbon Nanosheets Derived from V_(2)CF_(x)MXene for Capacitive Desalination

作　　者：张泽豪 王政 李海波[2] Zehao Zhang;Zheng Wang;Haibo Li(State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,College of Chemistry and Chemical Engineering,Ningxia University,Yinchuan 750021,China;Ningxia Key Laboratory of Photovoltaic Materials,School of Materials and New Energy,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学化学化工学院,煤炭高效利用与绿色化工国家重点实验室,银川750021 [2]宁夏大学材料与新能源学院,宁夏光伏材料重点实验室,银川750021

出　　处：《物理化学学报》2024年第8期18-27,共10页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(22272085,22169015)资助项目。

摘　　要：采用同源金属V_(2)CF_(x)MXene作为前驱体制备了三氧化二钒@多孔碳(V_(2)O_(3)@porous carbon,V_(2)O_(3)@PC)纳米片作为电容去离子(CDI)阳极,研究其脱盐特性。实验探究了在不同在碳化温度下V_(2)O_(3)@PC的结构、结晶度、润湿性、石墨化程度和电化学特性。研究表明,所制备的V_(2)O_(3)@PC呈现出典型的2D纳米片结构,高结晶度的V_(2)O_(3)纳米颗粒被高石墨化度的PC牢牢束缚。这种结构具有良好的界面润湿性和高导电性,因而可以促进电解质的渗透,加速界面电荷的转移以并促进盐离子的传输和扩散。此外,PC也能较好的抑制V_(2)O_(3)在多次循环后的体积膨胀。电化学结果表明,V的可逆电化学转化在一定程度上提高了Na^(+)的储存。当电压为1.2 V时,NaCl电导率为1000μS·cm^(−1)时,优化后的V_(2)O_(3)@PC电极具有高达2.20 mmol∙g^(−1)的脱盐容量,0.13 mmol∙g^(−1)∙min^(−1)的脱盐速率,62%的水回收率以及24.0 Wh∙m^(−3)的低能耗。Capacitive deionization(CDI)has been considered one of the most promising desalination technologies in the past decade.However,it faces challenges related to low salt removal efficiency in high salinity water.To address this issue,ion intercalation materials have been developed as anodes for CDI due to their abundant electroactive sites capable of accommodating large salty ions.V_(2)O_(3),a typical intercalation host,has garnered significant attention in the field of metal-ion batteries and appears to be a suitable candidate for CDI.Nevertheless,structural instability and slow ion diffusion,resulting from large volume expansion and low intrinsic electron/ion conductivity,present obstacles to its commercial application.Given their high specific surface area,abundant ion diffusion channels,and excellent conductivity,derivatives of metal-organic frameworks(MOFs)have become highly attractive in the electrochemical research community.In this study,2D V_(2)O_(3)@porous carbon(V_(2)O_(3)@PC)nanosheets were prepared using homologous metal V_(2)CF_(x)MXene as a precursor for CDI anodes,aiming to enhance salt removal capacity.The structure,crystallinity,wettability,graphitization degree,and electrochemical behavior of V_(2)O_(3)@PC were investigated by adjusting carbonization temperatures.The findings reveal that V_(2)O_(3)@PC exhibits a typical 2D nanosheet structure,with highly crystalline V_(2)O_(3)nanoparticles securely enveloped by graphitized PC.The electronic coupling between PC and V_(2)O_(3)ensures high electron conductivity.This unique structure demonstrates excellent interfacial wettability and high conductivity,facilitating electrolyte penetration,accelerating interfacial charge transfer,and enhancing salt ion diffusion.Additionally,the PC effectively restricts the volume expansion of V_(2)O_(3).Moreover,reversible electrochemical conversion between V3+/V4+contributes to Na^(+)storage,aiding the desalination/regeneration process.Notably,X-ray diffraction(XRD)analysis revealed the preferential growth of V_(2)O_(

关 键 词：电容去离子 三氧化二钒 金属有机框架 麦克烯 电化学 

分 类 号：O646[理学—物理化学]