电解法制备无硫膨胀石墨及柔性导热膜的研究  

Preparation of sulfur-free expanded graphite and flexible thermal conductive film by electrolysis

作　　者：赵康懿 刘军[1,2] 楠顶 董俊慧 白亮[1,2] Zhao Kang-yi;Liu Jun;Nan Ding;Dong Jun-hui;Bai Liang(School of Materials Science and Engineering,Inner Mongolia University of Technology,Inner Mongolia Hohhot O10051,China;Key Laboratory of Graphite(ene)Energy Storage and Coatings,Inner Mongolia Autonomous Region,Inner Mongolia Hohhot 010051,China;School of Chemistry and Chemical Engineering,Inner Mongolia University,Inner Mongolia Hohhot 010051,China)

机构地区：[1]内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051 [2]内蒙古自治区石墨(烯)储能与涂料重点实验室,内蒙古呼和浩特010051 [3]内蒙古大学化学化工学院,内蒙古呼和浩特010051

出　　处：《炭素技术》2022年第3期32-38,共7页Carbon Techniques

基　　金：内蒙古自治区科技成果转化项目(CGZH2018132);内蒙古自治区自然科学基金项目(2019MS05068);内蒙古自治区科技重大专项(2020ZD0024)。

摘　　要：传统方法制备的膨胀石墨含硫,硫在膨胀石墨中会恶化产品性能。因此,设计一种方法制备无硫膨胀石墨对于其能够更有效、广泛的应用是十分必要的。采用电解氧化法,以18目的天然鳞片石墨为原料进行电解,进一步经过高温处理得到蠕虫状的无硫膨胀石墨。通过单一控制变量法并结合正交试验得出了最佳制备条件:在外接电压为4 V的条件下,对电解液(V(CH_(3)COOH)=40 mL、m(KNO_(3))=4 g及60 mL的去离子水配制)中1 g的天然鳞片石墨电解4 h,再经过水洗、干燥及900℃的高温处理后,可以得到膨胀体积高达260 mL/g的无硫膨胀石墨。通过SEM、XRD、FT-IR及Raman对鳞片石墨、可膨胀石墨及膨胀石墨进行了形貌、结构及官能团的表征,结果表明,与鳞片石墨相比,NO_(3)^(-)及COO^(-)成功插入到了石墨层间,使可膨胀石墨的层间距增大,并经过高温处理后得到了具有纯度高,且兼有大孔、介孔及微孔孔隙的无硫膨胀石墨。将所得的无硫膨胀石墨进一步在N-甲基吡咯烷酮溶液中超声剥离24 h,经过离心收集沉淀物,在真空抽滤装置中抽滤制备柔性导热膜,其热扩散率可达804.693 mm^(2)/s,相比市面上的石墨膜的热扩散系数高出一倍多。Expanded graphite prepared by traditional methods is rich in sulfur,and sulfur in the expanded graphite deteriorates product performance.Therefore,it is very necessary to design a method to prepare sulfur-free expanded graphite for its more effective and wide application.In this paper,the electrolytic oxidation method is used to electrolyze the natural flake graphite with 18meshes as the raw material,and the worm-like sulfur-free expanded graphite is obtained after further high-temperature treatment.Through the single control variable method and combined with the orthogonal experiment to get the best preparation conditions:under the condition of the external power supply U=4 V,natural flake graphite of 1 g in the electrolyte(V(CH_(3)COOH)=40 mL,m(KNO_(3))=4 g and deionized water of 60 mL)is electrolyzed for 4 hours,and then washed,dried and treated at a high temperature of 900℃to obtain sulfur-free expanded graphite with an expansion volume of up to 260 mL/g.The morphology,structure and functional groups of flake graphite,expandable graphite and expanded graphite were characterized by SEM,XRD,FT-IR and Raman.The results show that compared with flake graphite,NO_(3)-and COO-are successfully inserted into the graphite layer.The interlayer spacing of expandable graphite is increased,and after high temperature treatment,sulfur-free expanded graphite with high purity,macropores,mesopores and microporous pores is obtained.The obtained sulfur-free expanded graphite was further ultrasonically stripped in N-methylpyrrolidone solution for 24 hours,the precipitate was collected by centrifugation,and then filtered in a vacuum filtration device to prepare a flexible thermally conductive film.Its thermal diffusion coefficient could reach 804.693 mm^(2)/s,which is more than doubled than that of the graphite film on the market.

关 键 词：电解法 无硫 石墨层间化合物 膨胀石墨 导热膜 

分 类 号：P619.252[天文地球—矿床学]