碳电极表面原位部分剥离石墨烯及其与法拉第赝电容电极材料的电化学复合

Gradual oxidation of carbon materials will be controlled electrochemically by advanced cyclic voltammetry and multistep/pluse potentiostatic/galvanostatic methods to introduce oxygen containing functional groups in the first step to decrease the attraction between the surface graphene nanosheets (GNS) and the bulk carbon. Positive potential limit can be increased by using organic solvent or ionic liquid for electrolyte. Deep oxidation of carbon can also be achieved through adding some water in the solution to produce oxygen and hydroxyl radicals. Then GNS can be partial exfoliated from graphite electrodes in the assistant of O2 or CO2 evolution to produce graphene electrode supported by carbon. Electrochemical growth of conducting polymer and/or inorganic oxide will be conducted after, as well as during the partial exfoliation to avoid restacking of GNS and to construct integrated network of graphene-conducting polymer/-oxide with high surface area to shorten ion transport paths. The large elastic buffer space provided by mechanical flexible graphene can improve the stability of pseudocapacitive materials through retarding the volume change induced cracking or crumbling during charging and discharging. High performance electrode materials for supercapacitor can be obtained based on the synergistic effects of graphene and pseudocapacitive materials in the composites. Pseudocapacitive properties of the composites will be investigated by cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS), while transmission electron microscope (TEM), atomic force microscope (AFM), scanning electron microscope (SEM), Raman spectroscopy (Raman), X-ray photoelectron microscopy (XPS), fourier transform infrared spectroscopy (FT-IR), as well as in situ AFM and FT-IR will be used to study the partial exfoliation of graphene from carbon electrode, growth of the pseudocapacitive materials and their distribution on graphene. Interfacial interactions between graphene and pseudocapacitive materials, as well as their precursors, and synergistic effects of graphene-conducting polymer-oxide will be analyzed. This work is aimed to explore the extended application of electrochemistry for the design and preparation of new functional materials.

控制碳电极逐级电化学氧化，借引入含氧官能团减弱表层碳与本体间作用力。利用有机溶液和离子液体增大阳极电位调控空间，借适量水加入控制氧自由基及羟基自由基的生成，进一步调控氧化能力，实现碳电极的深度氧化。辅以氧气或CO2逸出，原位部分剥离表层石墨烯，制备石墨烯电极。进行石墨烯上导电聚合物及氧化物的电化学生长，尤其是石墨烯部分剥离同时进行的电化学生长，避免石墨烯重新堆垛，并形成高比表面复合结构，同时缓解法拉第赝电容电极材料充放电过程中体积变化等引起的寿命降低等问题，借协同效应制备高性能超级电容器电极材料。利用CV、CP、EIS研究电容性能，利用TEM、AFM、Raman、XPS、IR等及原位AFM和IR研究石墨烯的部分剥离、石墨烯上聚合物及氧化物的生长、分布，分析聚合物/氧化物及其前体与石墨烯的界面相互作用、及石墨烯-聚合物-氧化物协同效应，为新材料设计及电场提供的特殊反应环境的巧妙利用提供探索。

设计了循环伏安、程序循环伏安、恒电位等电化学实验方案，借助扫描电位上限、电位上限停留时间和恒电位氧化时间调控，控制碳电极的逐级电化学氧化，引入适量含氧官能团，减弱表层碳与本体间的作用力，为石墨烯部分电化学剥离提供条件，并控制石墨烯的剥离程度和剥离深度。在含KNO3、K2CO3等不同电解质、表面活性剂的水溶液，及离子液体、有机溶液中进行了石墨烯部分电化学剥离研究，借助适量气体析出和电解质插层等作用，为石墨烯部分剥离提供动力。也借助电解质和溶剂的插层作用，进行了石墨烯的阴极电化学剥离研究。建立了一步电化学部分剥离、二步电化学部分剥离、阴极还原部分剥离等几种石墨烯部分电化学剥离实验方法，制备了Ex-GF、FEG、CEG、ECC、FCC、RTG等几种部分剥离石墨烯/石墨片电极。研究了MnO2、CoOx、FeOx、MoOx、Ni(OH)2-Co(OH)2、聚吡咯（PPy）、聚苯胺（PANI）等赝电容材料在石墨烯电极上的原位电化学生长，及PPy/PANI与VOx、WOx的原位电化学共生长，形成了高比表面多级微纳结构，大幅度提高了储能性能，并有效避免了石墨烯的重新堆垛，及缓解了赝电容材料充放电过程中体积变化等引起的寿命降低等问题。利用循环伏安、恒电流充放电、交流阻抗等方法研究了电极和组装的模拟超级电容器的储能性能，利用扫描电镜、透射电镜、原子力显微镜、拉曼光谱、X射线光电子能谱、红外光谱等方法等研究了石墨烯的部分剥离、石墨烯上聚合物及氧化物的生长、分布，分析了聚合物/氧化物及其前体与石墨烯的界面相互作用、及石墨烯-聚合物-氧化物协同效应，为新材料设计及电场提供的特殊反应环境的巧妙利用提供了有益的探索。在Adv. Func. Mater.、J. Mater. Chem. A等国际期刊上发表25篇标注本项目基金资助的SCI收录论文，其中2篇论文入选ESI前1%高被引论文。