發(fā)布時(shí)間：2018-12-13 08:29

【摘要】：超級(jí)電容器,已經(jīng)成為一種新型的儲(chǔ)能元件備受人們關(guān)注。超級(jí)電容器的電化學(xué)性能主要由電極材料的性質(zhì)決定。過(guò)渡金屬材料由于其良好的電化學(xué)性能而成為超級(jí)電容器電極最有前途的候選。本文通過(guò)靜電紡絲的方法設(shè)計(jì)合成了 NiO、檸檬酸改性NiO(NiO/CA)、無(wú)P123添加的 Co3O4(Co3O4/WP)、添加 P123 的 Co3O4(Co3O4/P)和 NiO/Co3O4納米纖維。并通過(guò)XRD、TG-DSC、TEM、SEM和N2吸脫附等手段對(duì)所得樣品進(jìn)行了表征和分析。采用循環(huán)伏安、恒電流充放電和交流阻抗的電化學(xué)測(cè)試手段對(duì)合成的納米纖維進(jìn)行了電化學(xué)性能的測(cè)試。研究發(fā)現(xiàn),未經(jīng)檸檬酸改性的NiO納米纖維結(jié)晶性良好,存在著由片狀顆粒堆積而形成的孔道,電流密度為5cmA·cm-2時(shí)的比電容可達(dá)到148 F·g-1,經(jīng)過(guò)檸檬酸改性后NiO/CA納米纖維為中空結(jié)構(gòu),并且比電容明顯增大,總電阻和電荷轉(zhuǎn)移電阻也有了不同程度的減小;通過(guò)Co3O4/WP納米纖維和Co3O4/P納米纖維的對(duì)比說(shuō)明,加入P123后,使樣品在焙燒后具有規(guī)則的棒狀纖維形貌,顆粒排列較為緊密。顆粒之間的堆積也比較有規(guī)律,形成的堆積孔更為均勻,便于電解質(zhì)的進(jìn)入和滲透。Co3O4/P納米纖維經(jīng)500℃焙燒,在電流密度為5mA·cm-2時(shí)的比電容可達(dá)到401F·g-1,為Co3O4/WP納米纖維的比電容的2.2倍;Co3O4/P納米纖維的總電阻較小僅為0.45Ω,電荷轉(zhuǎn)移電阻為0.20Ω;并且樣品經(jīng)過(guò)1000次循環(huán)后,其比電容僅僅下降了 6%;NiO/Co3O4納米纖維考察了不同Ni、Co質(zhì)量比,不同添加劑情況下各樣品的性能。檸檬酸和P123添加后,樣品具有規(guī)則的形貌,顆粒排列較為緊密,樣品為中空纖維結(jié)構(gòu)。顆粒之間形成的堆積孔較為均勻,便于電解質(zhì)的進(jìn)入和滲透。相同質(zhì)量配比制備的NiO/Co3O4納米纖維(NC-1)在電流密度為5mA·cm-2時(shí)的比電容可達(dá)到788F·g-1,較NiO納米纖維的比電容增大幾倍。NC-1納米纖維的總電阻較小,僅為0.45Ω,電荷轉(zhuǎn)移電阻為0.21Ω;并且樣品經(jīng)過(guò)1000次循環(huán)后,其比電容僅僅下降了 7%,表現(xiàn)出了很好的循環(huán)穩(wěn)定性。
[Abstract]:Supercapacitors have become a new type of energy storage components. The electrochemical properties of supercapacitors are mainly determined by the properties of electrode materials. Transition metal materials are the most promising candidates for supercapacitor electrodes due to their excellent electrochemical properties. In this paper, NiO, citric acid modified NiO (NiO/CA), Co3O4 (Co3O4/WP) without P123, Co3O4 (Co3O4/P) with P123 and NiO/Co3O4 nanofibers were designed and synthesized by electrospinning. The samples were characterized and analyzed by XRD,TG-DSC,TEM,SEM and N2 adsorption and desorption. The electrochemical properties of the synthesized nanofibers were measured by cyclic voltammetry, constant current charge-discharge and AC impedance. It was found that the NiO nanofibers without citric acid modified had good crystallinity, and there were pores formed by the stacking of flake particles. The specific capacitance of NiO nanofibers with current density of 5cmA cm-2 could reach 148F g-1. The NiO/CA nanofibers modified by citric acid have hollow structure, and the specific capacitance increases obviously, and the total resistance and charge transfer resistance also decrease to some extent. The comparison of Co3O4/WP nanofibers and Co3O4/P nanofibers shows that the samples prepared by P123 have regular shape of rod fibers and compact arrangement of particles after calcination. The stacking between particles is also regular, and the stacking pore is more uniform, which facilitates the entry and permeation of electrolytes. The specific capacitance of Co3O4/P nanofibers calcined at 500 鈩，

本文編號(hào)：2376242