Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have othe...Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have other advantages such as abundant resources,high safety and environmental friendliness.However,they still face problems such as insufficient specific capacitance,a short cycling life,and narrow operating voltage and temperature ranges,which are hindering their practical use.We provide a comprehensive overview of the fundamental theory of carbon-based ZICs and summarize recent research progress from three perspectives:the carbon cathode,electrolyte and zinc anode.The influence of the structure and surface chemical properties of the carbon materials on the capacitive performance of ZICs is considered together with theoretical guidance for advancing their development and practical use.展开更多
在微电子和微机械的高压应用中,如微型机器人、软致动器、皮肤电子、微型传感器和集成电子电路等,迫切需要高输出电压的储能/补给装置。近年来,高电压微型超级电容器(High voltage micro-supercapacitors,HVMSCs)因其微小型、便携式、...在微电子和微机械的高压应用中,如微型机器人、软致动器、皮肤电子、微型传感器和集成电子电路等,迫切需要高输出电压的储能/补给装置。近年来,高电压微型超级电容器(High voltage micro-supercapacitors,HVMSCs)因其微小型、便携式、柔韧性、高循环寿命及高功率/能量密度等优势而频繁作为功率补给装置应用到微机电系统,可满足一定范围的电压输出和能量供给,并且HVMSCs在电路中可作为储能器件应用可使电子产品更有可能趋向于集成式、高密度以及小型化。现有研究表明,增大MSCs的工作电压窗口,可以显著提升MSCs的输出能量密度,进而能最大限度地扩展其应用场合。因此,如何从材料、结构以及制造方法方面着手,制备全固态HVMSCs成为研究热点。基于此,首先对MSCs的电荷存储机制及电化学性能特征进行概述,其次分析高电压MSCs的实现原理,接着详细归纳HVMSCs的制造方法,主要包括高电压电极材料的制备(碳基材料、过渡金属氧化物、导电聚合物以及复合电极材料)以及高电压封装结构的制造(激光加工、喷墨打印、3D打印、丝网印刷、卷对卷印刷以及掩膜涂层),并且总结HVMSCs在储能功率器件、柔性传感以及可穿戴设施等方面的应用。在综合探讨HVMSCs的研究现状的基础上,最后对其在可穿戴和便携式电子设备等高电压领域的研究趋势和发展前景进行相应的展望。展开更多
Taking the selection of coal-tar pitch as precursor and KOH as activated agent, the activated carbon electrode material was fabricated for supercapacitor.The surface area and the pore structure of activated carbon wer...Taking the selection of coal-tar pitch as precursor and KOH as activated agent, the activated carbon electrode material was fabricated for supercapacitor.The surface area and the pore structure of activated carbon were analyzed by Nitro adsorption method. The electrochemical properties of the activated carbons were determined using two-electrode capacitors in 6 mol/L KOH aqueous electrolytes. The influences of activated temperature and mass ratio of KOH to C on the pore structure and electrochemical property of porous activated carbon were investigated in detail. The reasons for the changes of pore structure and electrochemical performance of activated carbon prepared under different conditions were also discussed theoretically. The results indicate that the maximum specific capacitance of 240 F/g can be obtained in alkaline medium, and the surface area, the pore structure and the specific capacitance of activated carbon depend on the treatment methods; the capacitance variation of activated carbon cannot be interpreted only by the change of surface area and pore structure, the lattice order and the electrolyte wetting effect of the activated carbon should also be taken into account.展开更多
Distinguished from commonly used Fe2O3 and Fe3O4,a three-dimensional multilevel macromicro-mesoporous structure of FeC2O4/graphene composite has been prepared as binderfree electrode for supercapacitors.The as-prepare...Distinguished from commonly used Fe2O3 and Fe3O4,a three-dimensional multilevel macromicro-mesoporous structure of FeC2O4/graphene composite has been prepared as binderfree electrode for supercapacitors.The as-prepared materials are composed of macroporous graphene and microporous/mesoporous ferrous oxalate.Generally,the decomposition voltage of water is 1.23 V and the practical voltage window limit is about 2 V for asymmetric supercapacitors in aqueous electrolytes.When FeC2O4/rGO hydrogel was used as the negative electrode and a pure rGO hydrogel was used as the positive electrode,the asymmetrical supercapacitor voltage window raised to 1.7 V in KOH(1.0 mol/L)electrolyte and reached up to 2.5 V in a neutral aqueous Na2SO4(1.0 mol/L)electrolyte.Correspondingly it also exhibits a high performance with an energy density of 59.7 Wh/kg.By means of combining a metal oxide that owns micro-mesoporous structure with graphene,this work provides a new opportunity for preparing high-voltage aqueous asymmetric supercapacitors without addition of conductive agent and binder.展开更多
The purpose of this paper is to show a laboratory scale implementation of a Thyristor Switched Capacitors （TSC） as an alternative for voltage regulation during a direct on line three-phase induction motor starting o...The purpose of this paper is to show a laboratory scale implementation of a Thyristor Switched Capacitors （TSC） as an alternative for voltage regulation during a direct on line three-phase induction motor starting on an emulated weak transmission line. Thyristor switched capacitor bank was chosen because it is a well known topology, considering the very nature of the direct starting induction motors, which represents a highly inductive load, the use of switched reactors becomes unnecessary. Such fact minimizes the introduction of harmonics components, and also reduces the cost of the implementation. The binary disposition of the banks allows a variable Var compensation with sixteen steps, in this case. The solution makes use of low cost devices combined with sliding window voltage and current measurement algorithm and a PI control with dead band control for achieve the shown experimental results, where the system is able to manage a typically 20% voltage drop, reducing it to less than 4%. The schematic of the developed circuit, the control technique and a quite simple method to calculate the binary weight capacitors banks are also presented.展开更多
Highly efficient, clean, and sustainable electrochemical energy storage technologies have been investigated extensively to counter the shortage of fossil fuels and increasingly prominent environmental problems. Superc...Highly efficient, clean, and sustainable electrochemical energy storage technologies have been investigated extensively to counter the shortage of fossil fuels and increasingly prominent environmental problems. Supercapacitors（SCs） have received wide attention as critical devices for electrochemical energy storage because of their rapid charging-discharging capability and long life cycle. Various transition metal oxides（TMOs）, such as MnO_2, NiO, Co_3O_4,and CuO, have been extensively studied as electrode materials for SCs. Compared with carbon and conducting polymers,TMO materials can achieve higher specific capacitance. For further improvement of electrochemical performance, hierarchically nano structured TMO materials have become a hot research area for electrode materials in SCs. The hierarchical nanostructure can not only offer abundant accessible electroactive sites for redox reactions but also shorten the ion diffusion pathway. In this review, we provide an overall summary and evaluation of the recent progress of hierarchically nano structured TMOs for SCs, including synthesis methods, compositions, structures, and electrochemical performances. Both single-phase TMOs and the composites based on TMOs are summarized. Furthermore, we also prospect the developing foreground of this field. In this view, the important directions mainly include： the nanocomposites of TMOs materials with conductive materials; the cobalt-based materials and the nickel-based materials; the improvement of the volume energy density, the asymmetric SCs, and the flexible all-solid-state SCs.展开更多
文摘Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have other advantages such as abundant resources,high safety and environmental friendliness.However,they still face problems such as insufficient specific capacitance,a short cycling life,and narrow operating voltage and temperature ranges,which are hindering their practical use.We provide a comprehensive overview of the fundamental theory of carbon-based ZICs and summarize recent research progress from three perspectives:the carbon cathode,electrolyte and zinc anode.The influence of the structure and surface chemical properties of the carbon materials on the capacitive performance of ZICs is considered together with theoretical guidance for advancing their development and practical use.
文摘在微电子和微机械的高压应用中,如微型机器人、软致动器、皮肤电子、微型传感器和集成电子电路等,迫切需要高输出电压的储能/补给装置。近年来,高电压微型超级电容器(High voltage micro-supercapacitors,HVMSCs)因其微小型、便携式、柔韧性、高循环寿命及高功率/能量密度等优势而频繁作为功率补给装置应用到微机电系统,可满足一定范围的电压输出和能量供给,并且HVMSCs在电路中可作为储能器件应用可使电子产品更有可能趋向于集成式、高密度以及小型化。现有研究表明,增大MSCs的工作电压窗口,可以显著提升MSCs的输出能量密度,进而能最大限度地扩展其应用场合。因此,如何从材料、结构以及制造方法方面着手,制备全固态HVMSCs成为研究热点。基于此,首先对MSCs的电荷存储机制及电化学性能特征进行概述,其次分析高电压MSCs的实现原理,接着详细归纳HVMSCs的制造方法,主要包括高电压电极材料的制备(碳基材料、过渡金属氧化物、导电聚合物以及复合电极材料)以及高电压封装结构的制造(激光加工、喷墨打印、3D打印、丝网印刷、卷对卷印刷以及掩膜涂层),并且总结HVMSCs在储能功率器件、柔性传感以及可穿戴设施等方面的应用。在综合探讨HVMSCs的研究现状的基础上,最后对其在可穿戴和便携式电子设备等高电压领域的研究趋势和发展前景进行相应的展望。
基金Project(2005CB623703) supported by the National Basic Research Program of China project(5JJ30103) supported bythe Natural Science Foundation of Hunan Province
文摘Taking the selection of coal-tar pitch as precursor and KOH as activated agent, the activated carbon electrode material was fabricated for supercapacitor.The surface area and the pore structure of activated carbon were analyzed by Nitro adsorption method. The electrochemical properties of the activated carbons were determined using two-electrode capacitors in 6 mol/L KOH aqueous electrolytes. The influences of activated temperature and mass ratio of KOH to C on the pore structure and electrochemical property of porous activated carbon were investigated in detail. The reasons for the changes of pore structure and electrochemical performance of activated carbon prepared under different conditions were also discussed theoretically. The results indicate that the maximum specific capacitance of 240 F/g can be obtained in alkaline medium, and the surface area, the pore structure and the specific capacitance of activated carbon depend on the treatment methods; the capacitance variation of activated carbon cannot be interpreted only by the change of surface area and pore structure, the lattice order and the electrolyte wetting effect of the activated carbon should also be taken into account.
基金supported by the National Natural Science Foundation of China (No.51673180 and No. 51673180)
文摘Distinguished from commonly used Fe2O3 and Fe3O4,a three-dimensional multilevel macromicro-mesoporous structure of FeC2O4/graphene composite has been prepared as binderfree electrode for supercapacitors.The as-prepared materials are composed of macroporous graphene and microporous/mesoporous ferrous oxalate.Generally,the decomposition voltage of water is 1.23 V and the practical voltage window limit is about 2 V for asymmetric supercapacitors in aqueous electrolytes.When FeC2O4/rGO hydrogel was used as the negative electrode and a pure rGO hydrogel was used as the positive electrode,the asymmetrical supercapacitor voltage window raised to 1.7 V in KOH(1.0 mol/L)electrolyte and reached up to 2.5 V in a neutral aqueous Na2SO4(1.0 mol/L)electrolyte.Correspondingly it also exhibits a high performance with an energy density of 59.7 Wh/kg.By means of combining a metal oxide that owns micro-mesoporous structure with graphene,this work provides a new opportunity for preparing high-voltage aqueous asymmetric supercapacitors without addition of conductive agent and binder.
文摘The purpose of this paper is to show a laboratory scale implementation of a Thyristor Switched Capacitors （TSC） as an alternative for voltage regulation during a direct on line three-phase induction motor starting on an emulated weak transmission line. Thyristor switched capacitor bank was chosen because it is a well known topology, considering the very nature of the direct starting induction motors, which represents a highly inductive load, the use of switched reactors becomes unnecessary. Such fact minimizes the introduction of harmonics components, and also reduces the cost of the implementation. The binary disposition of the banks allows a variable Var compensation with sixteen steps, in this case. The solution makes use of low cost devices combined with sliding window voltage and current measurement algorithm and a PI control with dead band control for achieve the shown experimental results, where the system is able to manage a typically 20% voltage drop, reducing it to less than 4%. The schematic of the developed circuit, the control technique and a quite simple method to calculate the binary weight capacitors banks are also presented.
基金supported by the National Natural Science Foundation of China (51202106,21671170 and 21673203)New Century Excellent Talents of the University in China (NCET-130645)+6 种基金the Innovation Scientists and Technicians Troop Construction Projects of Henan Province(164200510018)the Plan for Scientific Innovation Talent of Henan Provincethe Program for Innovative Research Team (in Science and Technology) in the University of Henan Province(14IRTSTHN004 and 16IRTSTHN003)the Science & Technology Foundation of Henan Province (122102210253 and 13A150019)the Science & Technology Foundation of Jiangsu Province (BK20150438)the Six Talent Plan (2015-XCL-030)China Postdoctoral Science Foundation (2012M521115)
文摘Highly efficient, clean, and sustainable electrochemical energy storage technologies have been investigated extensively to counter the shortage of fossil fuels and increasingly prominent environmental problems. Supercapacitors（SCs） have received wide attention as critical devices for electrochemical energy storage because of their rapid charging-discharging capability and long life cycle. Various transition metal oxides（TMOs）, such as MnO_2, NiO, Co_3O_4,and CuO, have been extensively studied as electrode materials for SCs. Compared with carbon and conducting polymers,TMO materials can achieve higher specific capacitance. For further improvement of electrochemical performance, hierarchically nano structured TMO materials have become a hot research area for electrode materials in SCs. The hierarchical nanostructure can not only offer abundant accessible electroactive sites for redox reactions but also shorten the ion diffusion pathway. In this review, we provide an overall summary and evaluation of the recent progress of hierarchically nano structured TMOs for SCs, including synthesis methods, compositions, structures, and electrochemical performances. Both single-phase TMOs and the composites based on TMOs are summarized. Furthermore, we also prospect the developing foreground of this field. In this view, the important directions mainly include： the nanocomposites of TMOs materials with conductive materials; the cobalt-based materials and the nickel-based materials; the improvement of the volume energy density, the asymmetric SCs, and the flexible all-solid-state SCs.
