Linjie 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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Keywords
Zheng Jin, Xiaomin Ren, Chuanli Qin, Bohong Li, Shuai Quan and Xuduo Bai
The purpose of this paper is to develop feasible composite electrodes with a long cycle life and large specific capacitance and to investigate optimal ratio between aniline and…
Abstract
Purpose
The purpose of this paper is to develop feasible composite electrodes with a long cycle life and large specific capacitance and to investigate optimal ratio between aniline and activated carbon materials.
Design/methodology/approach
PANI/AC composite electrode materials were synthesised by in situ polymerisation of aniline on activated carbon with ammonium persulphate as oxidant. Hybrid supercapacitors are assembled by putting Ni‐MH battery separator between positive and negative electrodes. The electrochemical performances of PANI/AC composite electrode materials and supercapacitors are studied.
Findings
The results show that the optimal ratio between aniline and activated carbon is 1:1.08. The specific capacitance of polyaniline electrode materials is 956 F g−1. The specific capacitance of supercapacitors is 159.37 F g−1. This result could be attributed to the pseudocapacitive effect of Ni(OH)2. What's more, the activated carbon addition reduced the resistance of polymer electrode materials thus improving the cyclic life.
Research limitations/implications
The supercapacitors can be used in the field of automobiles and can solve the problems of energy shortage and environmental pollutions.
Originality/value
A hybrid supercapacitor, which was immersed in alkaline solution, was assembled by putting Ni‐MH battery separator between two electrodes Ni(OH)2 as positive electrode and polyaniline composites as negative electrode. In the case of alkaline solution, the capacitive performance of hybrid supercapacitor was improved and excellent.
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Abstract
Purpose
This study sets out to compare the response of three‐dimensional (3D) woven composites subjected to high strain rate (HSR) compression loading with the dynamic response.
Design/methodology/approach
The 3D composites were manufactured using Kevlar woven fabrics with epoxy resin system utilising vacuum bag moulding approach. Samples were subjected to HSR compression loading in three directions using a modified split Hopkinson's pressure bar.
Findings
Peak stress and stiffness of 3D composites were higher for dynamic loading when compared with static loading in case of both in‐plane direction and out‐of‐plane direction. The peak stress and modulus increased with the increase in strain rate for both in‐plane direction and out‐of‐plane direction. Peak stress and dynamic modulus were higher when the samples were loaded in the fill direction compared with the warp direction loading. The failure strain in through‐the‐thickness direction was far higher than in in‐plane warp and fill direction.
Research limitations/implications
Other strength parameters of 3D composites could be studied.
Practical implications
The study provided the strength comparison of 3D composites in different situations.
Originality/value
The paper provide data on 3D composites for engineering applications.
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The function, utilization, and resource allocation of sport facilities in residential areas have attracted increasing attention in China along with the country's rapid economic…
Abstract
The function, utilization, and resource allocation of sport facilities in residential areas have attracted increasing attention in China along with the country's rapid economic development and the popularization of the health concept. To optimize the allocation of public sports resources and develop functions for sports facilities in China, this study analyzed existing policies concerning the planning and construction of sports facilities in residential areas and actual problems in the operation, management, and construction of sports facilities in the country. The analysis was conducted using document, investigation and expert consultation methods. Corresponding improvement measures were proposed by combining actual situations of urban sport participation of residents. Sports facilities in urban residential areas in China are facing various problems, such as inadequate quantity, uneven layout, poor management, and imperfect related laws and regulations as well as planning policies. Formulating sports facility planning policies and updating existing sports facilities are beneficial in relieving the sports facility shortage caused by the increased, diversified, and actual demands of residents. These measures could also guide the future construction of sports facilities in residential areas in high-density cities in China.