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2D Nanomaterials for Flexible Supercapacitors
Published in Ram K. Gupta, Energy Applications of 2D Nanomaterials, 2022
Yamin Zhang, Jinyang Zhang, Linrui Hou, Changzhou Yuan
Graphene film, also known as graphene paper, is a self-supporting graphene paper formed by multilayer graphene paper. It has distinguished electrical conductivity and flexibility and can be directly used as an electrode without binder, conductive agent, and current collector. When used as the electrode material of FSCs, it has excellent electrochemical performance [12]. Wang and his colleagues [13] fabricated graphene paper by vacuum filtration assembly method and first studied them as flexible electrode materials. However, due to the interaction between graphene layers, the irreversible agglomeration of graphene sheets occurs. This agglomeration reduces the effective contact area of graphene paper and limits ion diffusion, which shows unsatisfactory electrochemical performance. In order to solve this problem, the agglomeration of graphene can be avoided by adding a spacer. For example, the introduction of carbon black nanoparticles as a spacer greatly hindered the self-healing of graphene in the process of vacuum filtration [14]. In addition, graphene paper is formed by using graphene with a porous structure, which can provide more channels for ions and accelerate ion migration [15]. In addition to the above methods, template-assisted growth and wrinkling of graphene plates can also be used to prevent the aggregation of graphene plates, increase the surface area, and promote the transport of electrolyte ions in order to improve the electrochemical performance of FSCs [16].
Carbon Nanomaterials for Flexible Energy Storage Devices
Published in Sam Zhang, Materials for Energy, 2020
Huijuan Lin, Hui Li, Chenjun Zhang
In a conventional LIB, the electrode material is usually a lithium-containing transition metal oxide, which is uniformly ground with a conductive agent and a binder and coated on the metal current collector. The main disadvantages of the electrode prepared by this process are as follows: (1) the limited energy density of the battery due to the heavy metal foil, (2) the poor contact between the metal foil and the electrode material, and (3) non-flexibility of materials and structure. Hence, in flexible batteries, the design of the electrode material needs to be self-sustaining without using the current collector to accommodate deformations such as bending and folding. On this basis, two main solutions to construct flexible electrodes include the use of electrochemically active substances with intrinsic flexibility and deposition of active materials on flexible substrates.
Vanadium-Based Compounds for Supercapacitors
Published in Inamuddin, Rajender Boddula, Mohd Imran Ahamed, Abdullah Mohamed Asiri, Inorganic Nanomaterials for Supercapacitor Design, 2019
Xuan Pan, Wenyue Li, Zhaoyang Fan
Ions from the electrolyte and electrons from the electrode, both must be transported to the same surface location of the active material for faradic reaction to occur. Electrodes with a large SSA can facilitate electrolytic ions migration to the active surface reaction spots, but the low electronic conductivity of V2O5 significantly retards electrons from reaching the same locations. To address the conductivity limitation of V2O5, composite electrode structures have been extensively investigated. Although physically mixing V2O5 nanomaterial with a conductive agent such as carbon black can enhance the electrode conductivity to a certain degree, more sophisticated nanocomposite powders or freestanding hybrid nanostructures have also been developed, where the second phase serves as a conductive network and provides structural integrity and stability. Such a well-designed nanocomposite powder or 3D hybrid nanostructure can offer several merits, such as hierarchical pores for easy access by an electrolyte, thus facilitating rapid diffusion of electrolytic ions within the electrode material; a short diffusion length for ions into the active material due to its nanoscale dimension; and a high electrical conductivity of the overall electrode through the embedded conductive network.
Treatment of landfill leachate evaporation concentrate by a modified electro-Fenton method
Published in Environmental Technology, 2022
Guangcai Meng, Yanqiu Wang, Xiao Li, Huan Zhang, Xinyu Zhou, Zhongteng Bai, lizhuo Wu, Jinfeng Bai
The cathode used in this study is a self-developed Fe/AC/Ni cathode. The ferrous ions required for the electro-Fenton reaction were loaded onto the activated carbon via impregnation [23]. The activated carbon was washed with acid and alkali to remove impurities, then impregnated in an appropriate concentration of iron sulfate solution. The mixture was thoroughly stirred to uniformly disperse the ferrous ions in the activated carbon material. After impregnation, the activated carbon was calcined to form an iron-loaded activated carbon material in a nitrogen furnace. Acetylene black was used as the conductive agent to increase the conductivity of the electrode. Polytetrafluoroethylene (PTFE) emulsion was used as the binder. The loaded activated carbon material, acetylene black, and PTFE emulsion were evenly mixed, and anhydrous ethanol was used as a diluent to make electrode sheets, which were air-dried and fixed between two foam nickel sheets to generate the reaction electrode [24].
Copper foil after hydrothermal treatment in acidified tungstate solution as conductor- and binder-Free anode electrodes for high performance lithium-ion batteries
Published in Instrumentation Science & Technology, 2022
Xiaofeng Wu, Xingxing Jiang, Zhecheng Ye, Yingyi Zeng, Chunju Lv
The electrochemical performance was investigated at room temperature using coin-type cells (CR2025), in which the prepared hydrothermally treated copper foil was directly used as the working electrode after being cut into disks with a diameter of 10 mm. No electrochemically inactive conductive agent, polymer binder and further coating process were included for the fabrication of the electrode. The coin cells were assembled in an argon-filled glove box with water and oxygen contents less than 1 ppm, using Celgard 2500 as the separator, metallic lithium foil as the counter electrode, and 1 M lithium hexafluorophosphate dissolved in ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate (1:1:1 by volume) as the electrolyte.
Three-dimensionally architectured tungsten trioxide/tungsten trioxide hydrate/carbon cloth composite as a binder-free anode for lithium-ion batteries
Published in Instrumentation Science & Technology, 2020
Xi Lin, Wanjiao Li, Yuxiu Yao, Chunju Lv
A three-dimensionally architecture tungsten trioxide/tungsten trioxide hydrate/carbon cloth composite was prepared by a hydrothermal synthesis. Self-assembled tungsten trioxide and tungsten trioxide hydrate nanorods were directly grown on a conductive carbon cloth collector, which simplifies electrode processing without the use of a conductive agent and a binder. Benefiting from the unique three-dimensional hierarchical structure, the synthesized tungsten trioxide/tungsten trioxide hydrate/carbon cloth composite electrode exhibited a high reversible capacity, high rate capabilities, and excellent cycling performance.