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1 – 10 of 883Linjie Su, Bohong Li, Dongyu Zhao, Chuanli Qin and Zheng Jin
The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor.
Abstract
Purpose
The purpose of this paper is to prepare a new modified activated carbon fibers (ACFs) of high specific capacitance used for electrode material of supercapacitor.
Design/methodology/approach
In this study, the specific capacitance of ACF was significantly increased by using the phenolic resin microspheres and melamine as modifiers to prepare modified PAN-based activated carbon fibers (MACFs) via electrospinning, pre-oxidation and carbonization. The symmetrical supercapacitor (using MACF as electrode) and hybrid supercapacitor (using MACF and activated carbon as electrodes) were tested in term of electrochemical properties by cyclic voltammetry, AC impedance and cycle stability test.
Findings
It was found that the specific capacitance value of the modified fibers were increased to 167 Fg-1 by adding modifiers (i.e. 20 wt.% microspheres and 15 wt.% melamine) compared to that of unmodified fibers (86.17 Fg-1). Specific capacitance of modified electrode material had little degradation over 10,000 cycles. This result can be attributed to that the modifiers embedded into the fibers changed the original morphology and enhanced the specific surface area of the fibers.
Originality/value
The modified ACFs in our study had high specific surface area and significantly high specific capacitance, which can be applied as efficient and environmental absorbent, and advanced electrode material of supercapacitor.
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Piergiorgio Alotto, Massimo Guarnieri, Federico Moro and Andrea Stella
The purpose of this paper is to show the main features of the redox flow battery technology, present the current state-of-the-art of both industrial and research systems and to…
Abstract
Purpose
The purpose of this paper is to show the main features of the redox flow battery technology, present the current state-of-the-art of both industrial and research systems and to highlight the main research challenges.
Design/methodology/approach
The study is based on an extensive survey of recent literature as well as on the authors' own experience in the modelling of RFB systems.
Findings
RFBs present unique features which make them suitable for distributed storage and thus particularly interesting in the context of smart grids. Current research aims at resolving some outstanding issues which still limit the widespread use of RFBs.
Practical implications
A more widespread use of energy storage technologies, and RFBs in particular, will allow a much higher penetration of renewable energy sources.
Originality/value
The paper presents one of the few comprehensive studies on RFBs including both technological and modelling aspects.
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Wenhai Tan, Yichen Zhang, Yuhao Song, Yanbo Ma, Chao Zhao and Youfeng Zhang
Aqueous zinc-ion battery has broad application prospects in smart grid energy storage, power tools and other fields. Co3O4 is one of the ideal cathode materials for water zinc-ion…
Abstract
Purpose
Aqueous zinc-ion battery has broad application prospects in smart grid energy storage, power tools and other fields. Co3O4 is one of the ideal cathode materials for water zinc-ion batteries due to their high theoretical capacity, simple synthesis, low cost and environmental friendliness. Many studies were concentrated on the synthesis, design and doping of cathodes, but the effect of process parameters on morphology and performance was rarely reported.
Design/methodology/approach
Herein, Co3O4 cathode material based on carbon cloth (Co3O4/CC) was prepared by different temperatures hydrothermal synthesis method. The temperatures of hydrothermal reaction are 100°C, 120°C, 130°C and 140°C, respectively. The influence of temperatures on the microstructures of the cathodes and electrochemical performance of zinc ion batteries were investigated by X-ray diffraction analysis, scanning electron microscopy, cyclic voltammetry curve, electrochemical charging and discharging behavior and electrochemical impedance spectroscopy test.
Findings
The results show that the Co3O4/CC material synthesized at 120°C has good performance. Co3O4/CC nanowire has a uniform distribution, regular surface and small size on carbon cloth. The zinc-ion battery has excellent rate performance and low reaction resistance. In the voltage range of 0.01–2.2 V, when the current density is 1 A/g, the specific capacity of the battery is 108.2 mAh/g for the first discharge and the specific capacity of the battery is 142.6 mAh/g after 60 charge and discharge cycles.
Originality/value
The study aims to investigate the effect of process parameters on the performance of zinc-ion batteries systematically and optimized applicable reaction temperature.
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Georgina Harell and Tugrul U. Daim
In order to compliment the growing use of renewable energies in the US, additional technologies must be employed on the bulk power system. This paper aims to forecast the most…
Abstract
Purpose
In order to compliment the growing use of renewable energies in the US, additional technologies must be employed on the bulk power system. This paper aims to forecast the most probable energy storage technologies.
Design/methodology/approach
The methodology was deployed in two steps: evaluate the potential energy storage technologies that could complement a wind turbine or photovoltaic system; and forecast which of these technologies is best poised to become a viable solution to the energy storage problem facing these renewable technologies.
Findings
Based on the publication and patent data, compressed air energy is set to be the fastest growing complimentary technology to wind energy. Two of these types of plants are currently in existence today as mentioned previously indicating the technology is commercially available. This technology has great potential; however, implementing this technology involves finding or creating underground airtight caverns in usable locations.
Research limitations/implications
The number of variables have been limited due to the methodologies chosen for this analysis. The research can be expanded using other criteria such as cost, cost of capital, economies of scale, environmental concerns, social and political constraints.
Originality/value
This paper provides an assessment that was indicated as necessary by those who identified the need for the development of energy storage technologies for future electricity generation.
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Xiaoping Lin, Xiaoyan Li, Jiming Yao, Xianghong Li and Jianlin Xu
To develop electrode materials for supercapacitor with superior electrochemical performance and simple preparation process, the purpose of this study is to prepare flexible…
Abstract
Purpose
To develop electrode materials for supercapacitor with superior electrochemical performance and simple preparation process, the purpose of this study is to prepare flexible CC/NiS/a-NiS electrodes with self-supporting structure by loading hydrothermally synthesized a-NiS particles along with nano-NiS on carbon cloth by electroplating method.
Design/methodology/approach
The effects of current densities, temperatures and pH values on the loading amount and uniformity of the active substances during the plating process were investigated on the basis of optimization of surface morphology, crystalline structure and electrochemical evaluation as the cyclic voltammetry curves, constant current charge–discharge curves and AC impedance.
Findings
The a-NiS particles on CC/NiS/a-NiS were mostly covered by the plated nano-NiS, which behaved as a bulge and provided a larger specific surface area. The CC/NiS/a-NiS electrode prepared with the optimized parameter exhibited a specific capacitance of 115.13 F/g at a current density of 1 A/g and a Coulomb efficiency of 84% at 5 A/g, which is superior to that of CC/NiS electrode prepared by electroplating at a current density of 10 mA/cm2, a temperature of 55°C and a pH of 4, demonstrating its fast charge response of the electrode and potential application in wearable electronics.
Originality/value
This study provides an integrated solution for the development of specifically structured NiS-based electrode for supercapacitor with simple process, low cost and high electrochemical charge/discharge performance, and the simple and easy-to-use method is also applicable to other electrochemically active composites.
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F.F.M Shaikh, T.D. Dongale and R.K. Kamat
The overall purpose of this research paper largely depends on developing an easy method to synthesis a material suitable for supercapacitor application. This paper includes the…
Abstract
Purpose
The overall purpose of this research paper largely depends on developing an easy method to synthesis a material suitable for supercapacitor application. This paper includes the synthesis of, α-Co(OH)2, its structural, elemental and morphological properties and its supercapacitor properties.
Design/methodology/approach
Firstly, the electrolyte is prepared using binder free method, then electrodeposition is used to synthesize α-Co(OH)2 at 2 V. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM) are used to study the structural, elemental and morphological characteristics. The supercapacitor properties are investigated by using cyclic voltammetry, charging-discharging graph, stability test and electrochemical impedance spectroscopy (EIS).
Findings
Synthesis of α-Co(OH)2 is a tedious job as the temperature and use of weak base plays an important role. However, throughout electrodeposition, temperature is maintained using a water bath and weak base as the precursor. The presence of nitrate anions shows more interlayer space than that of ß-Co(OH)2 because of which free diffusion of the electrolyte is possible. Sheets structures are more visible in SEM images. Nanosheet like structure is observed in the film and such kind of structure provide higher surface area and higher specific capacitance. Usually, the surface morphology of cobalt hydroxide shows flower-like, spherical and nanocubes particles. The cross-section of the deposited film and it is found to be approximately 100 µm. In the forward and backward scan, oxidation and reduction peaks are clearly visible. However, such a behavior is reported as stable because of no further peaks of oxidation.
Originality/value
XRD and EDS confirms the growth of α-Co(OH)2. SEM images shows the porous nature of the film. Specific capacitance and energy density has been estimated at 5 mV s−1 is 780 F g−1 and 82 W h kg−1, respectively. The film was stable for 600 cycles showing 75 per cent capacitance retention. The voltage drop is 0.02 V for 0.5 A cm−2, indicating low resistance and good conductivity of the film. The specific power is estimated to be 15 W kg−1 for 1 A cm−2. The value of RESR, RCT, CDL and W is 4.83 Ohm, 1.273 Ohm, 0.00233 C and 0.717, respectively. Thus indicating α-Co(OH)2 to be better candidate for supercapacitor applications.
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The purpose of this paper is to describe, review, classify and analyze the current challenges in three-dimensional printing processes for combined electrochemical and microfluidic…
Abstract
Purpose
The purpose of this paper is to describe, review, classify and analyze the current challenges in three-dimensional printing processes for combined electrochemical and microfluidic fabrication areas, which include printing devices and sensors in specified areas.
Design/methodology/approach
A systematic review of the literature focusing on existing challenges is carried out. Focused toward sensors and devices in electrochemical and microfluidic areas, the challenges are oriented for a discussion exploring the suitability of printing varied geometries in an accurate manner. Classifications on challenges are based on four key categories such as process, material, size and application as the printer designs are mostly based on these parameters.
Findings
A key three-dimensional printing process methodologies have their unique advantages compared to conventional printing methods, still having the challenges to be addressed, in terms of parameters such as cost, performance, speed, quality, accuracy and resolution. Three-dimensional printing is yet to be applied for consumer usable products, which will boost the manufacturing sector. To be specific, the resolution of printing in desktop printers needs improvement. Printing scientific products are halted with prototyping stages. Challenges in three-dimensional printing sensors and devices have to be addressed by forming integrated processes.
Research limitations/implications
The research is underway to define an integrated process-based on three-dimensional Printing. The detailed technical details are not shared for scientific output. The literature is focused to define the challenges.
Practical implications
The research can provide ideas to business on innovative designs. Research studies have scope for improvement ideas.
Social implications
Review is focused on to have an integrated three-dimensional printer combining processes. This is a cost-oriented approach saving much of space reducing complexity.
Originality/value
To date, no other publication reviews the varied three-dimensional printing challenges by classifying according to process, material, size and application aspects. Study on resolution based data is performed and analyzed for improvements. Addressing the challenges will be the solution to identify an integrated process methodology with a cost-effective approach for printing macro/micro/nano objects and devices.
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Yuming Guan, Jingbo Mu, Hongwei Che, Xiaoliang Zhang and Zhixiao Zhang
The purpose of this study is to design carbon electrode materials for high performance electric double-layer capacitors (EDLCs) with pores that are large enough and have suitable…
Abstract
Purpose
The purpose of this study is to design carbon electrode materials for high performance electric double-layer capacitors (EDLCs) with pores that are large enough and have suitable pore size distribution for the electrolyte to access completely to improve EDLCs’ electrochemical performance.
Design/methodology/approach
This study develop an improved traditional KOH activation method, and a series of micro-meso hierarchical porous carbons have been successfully prepared from phenol formaldehyde resin by combining polyethylene glycol (PEG) and conventional KOH activation.
Findings
As evidenced by N2 adsorption/desorption tests, the obtained samples present Types IV and I-IV hybrid shape isotherms compared with KOH-activated resin (typical of Type I). The sample AC2-7-1, which the addition quantity of PEG is 25 per cent PF (weight ration) activated at 700? For 1 h is considered as the optimum preparation condition. It exhibits the highest specific capacitance value of 240 F/g in 30 wt% KOH aqueous electrolytes because of its higher specific surface area (2085 m2/g), greater pore volume (1.08 cm3/g) and the maximum mesoporosity (43 per cent). In addition, the capacity decay of this material is only 3.1 per cent after 1000 cycles.
Originality/value
The materials that are rich in micropores and mesopores show great potential in EDLC capacitors, particularly for applications where high power output and good high-frequency capacitive performances are required.
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Cara Greta Kolb, Maja Lehmann, Johannes Kriegler, Jana-Lorena Lindemann, Andreas Bachmann and Michael Friedrich Zaeh
This paper aims to present a requirements analysis for the processing of water-based electrode dispersions in inkjet printing.
Abstract
Purpose
This paper aims to present a requirements analysis for the processing of water-based electrode dispersions in inkjet printing.
Design/methodology/approach
A detailed examination of the components and the associated properties of the electrode dispersions has been carried out. The requirements of the printing process and the resulting performance characteristics of the electrode dispersions were analyzed in a top–down approach. The product and process side were compared, and the target specifications of the dispersion components were derived.
Findings
Target ranges have been identified for the main component properties, balancing the partly conflicting goals between the product and the process requirements.
Practical implications
The findings are expected to assist with the formulation of electrode dispersions as printing inks.
Originality/value
Little knowledge is available regarding the particular requirements arising from the systematic qualification of aqueous electrode dispersions for inkjet printing. This paper addresses these requirements, covering both product and process specifications.
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Shu-hao Deng, Yu Wang and Xi Yang
The purpose of this paper is to improve the conductivity and processability of polyaniline (PANI).
Abstract
Purpose
The purpose of this paper is to improve the conductivity and processability of polyaniline (PANI).
Design/methodology/approach
The study opted for synthesis of the conductive PANI/polyvinyl alcohol (PVA) composite film, co-doped with 5-sulphosalicylic acid and sulphuric acid. Using an electrochemical method, a small amount of silver (Ag) was electrodeposited on the film. The PVA/PANI and PVA/PANI/Ag composite films were characterised by scanning electron microscope, X-ray diffraction and infrared. The composite deposition mechanism of the composite film was investigated by cyclic voltammetry for the first time.
Findings
The conductivity of the optimum PVA/PANI composite film reached 21.2 S · cm−1.Then, a small amount of Ag was deposited on the PVA/PANI film, and the conductivity significantly increased by 1250 S · cm−1. Through appropriate degree of stretching, the conductivity of the films was enhanced. The results indicate that uniform PVA/PANI fibres and dendritic Ag can combine to form complete three-dimensional conductive networks that exhibit better conductivity and mechanical properties. The cyclic voltammetry curves reveal that the dedoping potential of PANI was more negative than the reduction potential of Ag. Therefore, the procedure for the deposition of Ag on the PANI/PVA composite film cannot decrease the conductivity.
Practical implications
This paper for the first time described and revealed the effective and practical synthesis approach and composite mechanism to prepare multi-types metal-conductive polymer composites and improve the conductivity of a conductive polymer with a less expense and one-step electrochemical method.
Originality/value
This paper first explored galvanostatic oxidation to synthesise a PANI composite film to resolve the processability and conductivity of PANI by co-doped with mixed acids and deposited Ag on film. Furthermore, for the first time, the composite mechanism of metal and conductive polymer was studied.
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