A comparison of the performance of graphene-based supercapacitors is difficult, owing to the variety of production methods used to prepare the materials. To the best of our knowledge, there has been no systematic investigation into the effect of the graphene production method on the supercapacitor performance. In this work, we compare graphene produced through several routes. This includes anodic and cathodic electrochemically exfoliated graphene, liquid phase exfoliated graphene, graphene oxide, reduced graphene oxide, and graphene nanoribbons. Graphene oxide exhibited the highest capacitance of approximately 154 F g−1 in 6 M KOH at 0.5 A g−1 attributed to oxygen functional groups giving an additional pseudocapacitance and preventing significant restacking; however, the capacitance retention was poor, owing to the low conductivity. In comparison, the anodic electrochemically exfoliated graphene exhibited a capacitance of approximately 44 F g−1, the highest of the ‘pure’ graphene materials, which all exhibited superior capacitance retention, owing to their higher conductivity. The cyclability of all of the materials, with the exception of reduced graphene oxide (70 %), was found to be greater than 95 % after 10 000 cycles. These results highlight the importance of matching the graphene production method with a specific application; for example, graphene oxide and anodic electrochemically exfoliated graphene would be best suited for high energy and power applications, respectively. 相似文献
Graphene oxide (GO) nanosheets are readily reduced by aniline above room temperature in an aqueous acid medium, with the aniline simultaneously undergoing oxidative polymerization to produce the reduced graphene oxide‐polyaniline nanofiber (RGO‐PANi) composites. The resulting RGO‐PANi composites and RGO (after dissolution of PANi) were characterized by XPS, XRD analysis, TGA, UV–visible absorption spectroscopy, and TEM. It was also found that the RGO‐PANi composites exhibit good specific capacitance during galvanostatic charging–discharging when used as capacitor electrodes.
Commercialization of Li–S in present scenario is obstructed by poor performance of cathode and its compatibility with electrolyte used. Here in this work, in order to improve the electrochemical performance all solid state Li–S battery, solid electrolyte (SE) formed by composition of lithium sulfide (Li2S) and phosphorus pentasulfide (P2S5) combinedly called LPS is used. The modified carbon in the form of graphene oxide (GO) and reduced graphene oxide (rGO) as additive is used to provide better electron conduction pathway. High conductivity of the order 10−4 S cm−1 of prepared LPS overcomes the major drawback of insulating nature of sulfur. The coin cells are fabricated by using above mentioned material as a cathode material, LPS as SE, and lithium foil as anode. The prepared nanocomposites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) to study structural and morphological properties. Energy dispersive X-ray spectroscopy (EDS) images of the cathode surface confirms the uniform spreading of material. The electrochemical performance of coin cell is studied by Galvanostatic charge-discharge plot at 0.1 C to check the compatibility of composite and electrolyte prepared. The cells having additive material GO and rGO with host sulfur show better results as compared to the cell having pristine sulfur. 相似文献
利用化学法制备氧化石墨烯(GO)与石墨烯(RGO),然后以水热法制备Fe3O4空心球/RGO复合吸波材料。XRD测试结果表明成功合成了具有立方结构的Fe3O4;SEM,TEM分析结果表明复合材料结构分布均匀,粒径约为100 nm。测试了材料在2~18 GHz波段的电磁参数,模拟计算了材料的反射率,结果显示复合材料的吸波性能比RGO有明显提升。当匹配厚度为7 mm时,复合材料具有两个吸收峰:在5.5 GHz处吸收峰为–9.5 d B,在16.5GHz处出现最大吸收峰–36 d B。 相似文献
Owing to their versatility and unique characteristics, graphene-based materials have been used extensively for the development of electrochemical sensors and biosensors. The key to the maximum potential of these materials is the understanding of the role their structure plays in their modification processes. Herein, we summarize some structural characteristics of graphene oxide (GO) and reduced graphene oxide (rGO) and explore different surface modification methods for electrochemical sensing applications. surveyed the most recent applications of these materials as (bio)sensors, particularly for environmental monitoring and health-related applications, such as quantification of biomarkers and metabolites and detection of cancer cells. The low detection limits, selectivity toward target molecules, and robustness of GO- and rGO-based electrodes render them critical materials for the preparation of sensors for routine analysis and monitoring. 相似文献
