Porous Co3O4 nanorods as superior electrode material for supercapacitors and rechargeable Li-ion batteries

Porous aggregated nanorods of Co₃O₄ with a surface area of ~100 m² g^?1 synthesized without using any templates or surfactants give very high specific capacitance of ~780 F g^?1 when used as electrode in a faradaic supercapacitor, with a cycle life of more than 1,000 cycles. Further, in Li-ion batteries when used as an anode, the Co₃O₄ nanorods achieved a capacity of 1155 mA h g^?1 in the first cycle and upon further cycling it is stabilized at 820 mA h g^?1 for more than 25 cycles. Detailed characterization indicated the stability of the material and the improved performance is attributed to the shorter Li-insertion/desertion pathways offered by the highly porous nanostructures. The environmentally benign and easily scalable method of synthesis of the porous Co₃O₄ nanorods coupled with the superior electrode characteristics in supercapacitors and Li-ion batteries provide efficient energy storage capabilities with promising applications.     

Ultrafine metatitanic acid electrode for ultrafast lithium ion batteries

Energy storage devices that can perform both high power and high energy operations are greatly needed for hybrid and plug-in hybrid electric vehicles and for systems by which the power generation is distributed. Here we show an easily prepared electrode material for lithium ion batteries which demonstrates high energy density, outstanding rate capabilities and long cycle life, comparable to those of supercapacitors. At a rate equivalent to a 6-minute total charge/discharge, the as-prepared metatitanic acid exhibits a life of over 7000 charge/discharge cycles while still retaining up to 87.5% of its original capacity. Furthermore, the electrode using this material can be fully charged in one minute while still maintaining a high energy density.     

Room Temperature Ionic Liquid-based Electrolytes as an Alternative to Carbonate-based Electrolytes

The issue of the safety of Li-ion batteries is becoming more critical with the increase in their size for applications in large energy storage devices, such as hybrid electric vehicles (HEVs), and energy storage systems (ESSs) for smart grids. The thermal runaway of Li-ion batteries is considered to be caused by their flammable components, such as the volatile carbonate solvents of electrolytes. Room temperature ionic liquids (RTILs) have recently received much attention because of their characteristics of non-flammability and non-volatility. In addition, RTILs show high ionic conductivity and a wide electrochemical stability window. Therefore, RTIL-based electrolytes are considered one of the most promising candidates to improve the safety of Na-ion, as well as Li-ion batteries; indeed, RTIL-based electrolytes have shown excellent improvements in terms of thermal stability and electrochemical performance. This review provides a comprehensive overview of selected RTIL materials, including their physicochemical and electrochemical properties. Moreover, we discuss the failure mechanisms of certain RTIL-based electrolytes with various electrodes to suggest alternative strategies for improving their electrochemical performance.     

储能用锂离子动力电池研究进展

锂离子电池具有储能密度高、能量效率高、工作温度范围宽、自放电小、循环寿命长等优点,在储能领域具有重要的应用前景。结合作者所在单位的工作对磷酸铁锂、锰酸锂、钛酸锂等储能用锂离子动力电池的功能特点和存在问题进行了简要分析,提出了发展高容量、长寿命和低成本储能用锂离子电池的一些初步建议。     

混合供电系统中退役电池的模块化储能操作优化

将退役的动力电池用于混合供电系统可有效地降低投资成本，而针对退役电池储能系统的操作优化则可降低混合供电系统的操作费用，并提升混合供电系统的运行收益。以多个初始容量存在差异的电池组构成的退役电池储能系统为对象，在综合考虑退役电池容量衰退特性和电池组初始状态差异的基础上，构建了以年总费用最小为目标的混合供电系统操作优化模型，并将该方法用于一个由光伏发电和储能电池系统构成的混合供电系统的操作优化中。研究表明：储能电池系统中多组退役电池初始状态的差异，使得各电池组在操作过程中的充放电顺序和频率存在显著差异；储能电池系统的操作优化可有效缓解电池容量衰退，与固定比例调度流程相比，该储能电池系统的年总费用更低。     

Nano-structured porous carbon materials for catalysis and energy storage

Porous carbon materials are of interest in many applications because of their high surface area and physicochemical properties. For particular application, the surface of porous carbon material usually needs to be modified or functionalized according to a specific requirement. In this review, methods of synthesis of porous carbon material core shell structure, methods of functionalizing porous carbon material through direct incorporation of heteroatom in carbon synthesis, halogenation, sulfonation, surface oxidation, grafting are examined. The method of characterizing the functionalized carbon material (bulk, surface, internal and external) and its application in the field of catalysis and energy storage (Li-ion batteries, capacitors/supercapacitors), are also subjects of focus.     

Carbon-doped surface unsaturated sulfur enriched CoS2@rGO aerogel pseudocapacitive anode and biomass-derived porous carbon cathode for advanced lithium-ion capacitors

As a hybrid energy storage device of lithium-ion batteries and supercapacitors, lithium-ion capacitors have the potential to meet the demanding needs of energy storage equipment with both high power and energy density. In this work, to solve the obstacle to the application of lithium-ion capacitors, that is, the balancing problem of the electrodes kinetic and capacity, two electrodes are designed and adequately matched. For the anode, we introduced in situ carbon-doped and surface-enriched unsaturated sulfur into the graphene conductive network to prepare transition metal sulfides, which enhances the performance with a faster lithium-ion diffusion and dominant pseudocapacitive energy storage. Therefore, the lithium-ion capacitors anode material delivers a remarkable capacity of 810 mAh∙g^–1 after 500 cycles at 1 A∙g^–1. On the other hand, the biomass-derived porous carbon as the cathode also displays a superior capacity of 114.2 mAh∙g^–1 at 0.1 A∙g^–1. Benefitting from the appropriate balance of kinetic and capacity between two electrodes, the lithium-ion capacitors exhibits superior electrochemical performance. The assembled lithium-ion capacitors demonstrate a high energy density of 132.9 Wh∙kg^–1 at the power density of 265 W∙kg^–1, and 50.0 Wh∙kg^–1 even at 26.5 kW∙kg^–1. After 10000 cycles at 1 A∙g^–1, lithium-ion capacitors still demonstrate the high energy density retention of 81.5%.     

First-principles modeling for optimal design,operation, and integration of energy conversion and storage systems

Energy and electricity consumption is expected to increase in the foreseeable future. Concurrently, sustainability concerns of fossil-based energy resources have motivated the use of renewable and reusable energy resources, and the use of more efficient energy-converting and energy-consuming systems. Consequently, for the past decade, there have been major theoretical and experimental advances in (1) energy generation from renewable and reusable resources and (2) energy-consuming and energy-converting devices. This review article focuses on the recent theoretical advances in renewable energy conversion devices such as photovoltaic and fuel cells, and in energy storage devices such as rechargeable batteries, flow batteries, and supercapacitors. Due to similar chemistry, electrochemistry, and physics of these systems, modeling similarities between different energy systems are highlighted. This review puts into perspective how first-principles mathematical modeling has contributed to systematic advances in the optimal design, operation, and integration of these systems. © 2018 American Institute of Chemical Engineers AIChE J, 65: e16482 2019     

有机介质体系锂离子电容器

锂离子电容器（lithium ion capacitor，LIC）是一种新型的电化学储能器件，可以填补锂离子电池和超级电容器两者之间的性能空白，是下一代高能量密度超级电容器的前进方向。本文首先介绍了锂离子电容器的储能原理分为电解液消耗机制、锂离子交换机制以及混合机制，并围绕高能量密度的有机介质体系锂离子电容器，着重阐述了各类电容及电池型正负极材料的性质特点、优化方向及其研究现状，指出不同材料的优缺点及改性方法。同时叙述了与产业应用相关的预嵌锂技术、隔膜、电解液以及体系匹配等方面的研究现状，总结归纳了这些部件的研究对于比能量、功率、安全、稳定性等性能的提升。在产业化应用方面，针对锂离子电容器不同于锂离子电池和传统超级电容器的性能指标，总结其在智能物流、起重机电源、机器人电源及轨道交通等方面独特的应用前景。最后展望了电极材料微观结构优化及功能集成、电解液专用化，预嵌锂成本进一步压缩、以及检测及原位表征方法的开发等锂离子电容器未来的发展方向。     

微晶玻璃储能应用研究进展

储能电介质材料是制作脉冲功率电容器的核心材料,在脉冲功率电源、高功率电子器件、高能量密度武器、智能电网系统等基础科研和工程技术领域均有着广阔的前景。微晶玻璃具有很高的电击穿强度,是一类重要的电介质储能材料。本文在简要介绍储能电介质材料的性能评价参数及其相关物理意义的基础上,概述了微晶玻璃储能材料的主要制备方法及其优缺点,重点阐述了微晶玻璃储能材料的主要研究体系及其相关研究进展,最后探讨了微晶玻璃储能材料的未来发展方向及应用前景。     

20 V stack of aqueous supercapacitors with carbon (−), titanium bipolar plates and CNT‐polypyrrole composite (+)

A 20 V stack of 19 supercapacitors was fabricated from titanium bipolar plates (150 × 150 × 0.1 mm³) coated on each side with carbon nanotubes and polypyrrole composite (+) and pigment carbon black (?), and microporous polymeric separators containing aqueous KCl. Internal sealing of each cell in the stack was achieved by placing a silicone rubber washer between neighboring bipolar plates. The stack was tested by high voltage cyclic voltammetry, galvanostatic charging and discharging, and electrochemical impedance spectroscopy. It approached 25 kW/kg in maximum specific power and 3.64 Wh/kg in specific energy. Performance of the stack through intermittent charging‐discharging tests in a storage period of 10 months (still ongoing) remained fairly stable. For example, it exhibited almost zero decay in capacitance after 1000 continuous galvanostatic charging‐discharging cycles in the first month of storage (10 V), and less than 6% loss in the seventh month (19 V). © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Recent Advances in Electrochemical Performances of Graphene Composite (Graphene-Polyaniline/Polypyrrole/Activated Carbon/Carbon Nanotube) Electrode Materials for Supercapacitor: A Review

The latest trend in the direction of miniaturized portable electronic devices has brought up necessitate for rechargeable energy sources. Among the various non conventional energy devices, the supercapacitor is the promising candidate for gleaning the energy. Supercapacitor, as a new energy device that colligates the gap between conventional capacitors and batteries, it has attracted more attention due to its high power density and long cycle life. Many researchers work on, synthesizing new electrode material for the development of supercapacitor. The electrode material possesses salient structure and electrochemical properties exhibit the efficient performance of the supercapacitor. Graphene has high carrier mobility, thermal conductivity, elasticity and stiffness and also has a theoretical specific capacitance of 2630 m²g^??1 corresponds to a specific capacitance of 550 Fg^??1. This article summarizes and reviews the electrochemical performance and applications of various graphene composite materials such as graphene/polyaniline, graphene/polypyrrole, graphene/metal oxide, graphene/activated carbon, graphene/carbon nanotube as an electrode materials towards highly efficient supercapacitors and also dealt with symmetric, asymmetric and hybrid nature of the graphene based supercapacitor.     

The role of nanomaterials in redox-based supercapacitors for next generation energy storage devices

The development of more efficient electrical storage is a pressing requirement to meet future societal and environmental needs. This demand for more sustainable, efficient energy storage has provoked a renewed scientific and commercial interest in advanced capacitor designs in which the suite of experimental techniques and ideas that comprise nanotechnology are playing a critical role. Capacitors can be charged and discharged quickly and are one of the primary building blocks of many types of electrical circuit, from microprocessors to large-sale power supplies, but usually have relatively low energy storage capability when compared with batteries. The application of nanostructured materials with bespoke morphologies and properties to electrochemical supercapacitors is being intensively studied in order to provide enhanced energy density without comprising their inherent high power density and excellent cyclability. In particular, electrode materials that exploit physical adsorption or redox reactions of electrolyte ions are foreseen to bridge the performance disparity between batteries with high energy density and capacitors with high power density. In this review, we present some of the novel nanomaterial systems applied for electrochemical supercapacitors and show how material morphology, chemistry and physical properties are being tailored to provide enhanced electrochemical supercapacitor performance.     

Application of ionic liquids-based Li-ion battery electrolyte andimprovement of electrochemical properties

近年来锂离子电池在动力电池方面被寄予厚望,但安全性是制约其应用的关键之一,而其安全性与电解液性质密切相关。离子液体具有不可燃、不挥发、热稳定性好等优点,可作为电解液以替代传统有机溶剂应用于锂离子电池中。基于现有研究,本文阐述了各类离子液体作为锂离子电池电解液的优异性和不足点,进而综述了各种针对离子液体自身不足采取的性能改进方法,并对该方向的进一步研究进行了展望。     

离子液体基锂离子电池电解液的应用与性能改进

近年来锂离子电池在动力电池方面被寄予厚望,但安全性是制约其应用的关键之一,而其安全性与电解液性质密切相关。离子液体具有不可燃、不挥发、热稳定性好等优点,可作为电解液以替代传统有机溶剂应用于锂离子电池中。基于现有研究,本文阐述了各类离子液体作为锂离子电池电解液的优异性和不足点,进而综述了各种针对离子液体自身不足采取的性能改进方法,并对该方向的进一步研究进行了展望。     

Effect of processing parameters on the pulsed-spouted microwave vacuum drying of puffed salted duck egg white/starch products

A puffed food using salted duck egg white and starch as ingredients was produced by using a novel pulsed-spouted microwave vacuum drying (PSMVD) technique. In this study, three types of samples (ratios of salted duck egg white to starch 1:10, 3:10, and 5:10) were prepared and the moisture content of these samples was dehydrated to about 12% in a PSMVD dryer, then the samples were under different microwave powers (1.34 kW, 2.01 kW, and 2.68 kW) for puffing. The product volume expansion ratio, textural crispness (breaking forces), color parameters (L*, a* and b*), and sensory scores were determined. It was observed that microwave power and different ratios of salted duck egg white to starch had a significant effect on the expansion effect of the samples. The results indicated that the best product quality was obtained under the ratio of salted duck egg white to starch at 3:10 and microwave power at 2.01 kW.     

Hybrid battery-supercapacitor storage for an electric forklift: a life-cycle cost assessment

Supercapacitors, more properly named electrochemical capacitors (EC), have a great potential in constituting the premium power reserve in a variety of energy- and power-intensive applications in transport and in electricity grids. EC may be used in conjunction with electrochemical storage systems, such as the batteries of various chemistries (lead-acid, sodium-nickel chloride or sodium-sulphur, nickel-metal hydride and even lithium-based systems), in a hybrid configuration where the functions of energy and power can be conveniently separated between the two storage devices and then optimized. Recently, an electric forklift has been commercialized with such a hybrid storage system, without any demonstrated specification of the advantages achievable with this configuration. In this article, the effective technical and economical benefits of this EC integration are theoretically and experimentally evaluated, by means of a conventional electric forklift. The reference vehicle drivetrain is modified by combining a conventional traction lead-acid battery, already used in the vehicle, and a commercial EC. The performances of the modified electric forklift are simulated with already developed vehicle and components models and validated with experimental data. Simulations and electrical tests confirm the functional relationship, expressed in exponential form, between battery lifetime and peak current and demonstrate the technical and economical potentialities of the use of these hybrid configurations, such as the increased efficiency and the prolonged battery life (more than doubling the life of the battery without EC), due to the reduced battery operating stress, and an economical saving (about 30 %), able to compensate initial extra-costs for vehicle modification and battery replacement.     

表面化学反应控制制备多级结构电极材料及性能

超级电容器和锂离子电池等储能设备的研究和开发日益受到人们的关注。对于超级电容器和锂离子电池等储能设备,其电化学性能主要取决于电极材料,因此高效储能材料的制备成为开发高效储能设备的关键。本文主要介绍了多级结构过渡金属氧化物基电极材料的制备及性能,重点阐述了本实验室近年来在研制高性能超级电容器和锂离子电池方面的相关工作:基于表面化学反应控制制备多级结构金属氧化物、金属氢氧化物/碳嵌入式纳米杂化物以及多种三维结构的多元复合电极材料,表现出优异的电化学性能。     

Process systems opportunities in power generation,storage and distribution

This paper presents an overview of the current process systems opportunities in power generation, storage and distribution. It puts in perspective how process systems engineering (PSE) has contributed to the area and explores the current technical problems that PSE can contribute to. Fuel cells, solar cells, wind turbines, flow batteries and rechargeable batteries as well as their interactions with the smart grid are considered. PSE has contributed and will contribute to the design as well as optimal integration and operation of power generators, storage systems and power grids, through mathematical modeling, control and optimization.     

A Study of Carbon Nanofibers and Active Carbon as Symmetric Supercapacitor in Aqueous Electrolyte: A Comparative Study

Symmetric supercapacitors are fabricated by carbon nanofibers (CNF) and activated carbon (AC) using similar proportions of 7 wt% polyvinylidene fluoride (PVDF) polymer binder in an aqueous electrolyte. In this study, a comparison of porous texture and electrochemical performances between CNFs and AC based supercapacitors was carried out. Electrodes were assembled in the cell without a current collector. The prepared electrodes of CNFs and AC present Brunauer-Emmett-Teller (BET) surface area of 83 and 1042 m²/g, respectively. The dominant pore structure for CNFs is mesoporous while for AC is micropore. The results showed that AC provided higher specific capacitance retention up to very fast scan rate of 500 mV/s. AC carbon had a specific capacitance of 334 F/g, and CNFs had 52 F/g at scan rate 5 mV/s in aqueous solution. Also, the results indicate the superior conductivity of CNFs in contrast to AC counterparts. The measured equivalent series resistance (ESR) showed a very small value for CNFs (0.28 Ω) in comparison to AC that has an ESR resistance of (3.72 Ω). Moreover, CNF delivered higher specific power (1860 W/kg) than that for AC (450 W/kg). On the other hand, AC gave higher specific energy (18.1 Wh/kg) than that for CNFs (2 Wh/kg).This indicates that the AC is good for energy applications. Whereas, CNF is good for power application. Indeed, the higher surface area will lead to higher specific capacitance and hence higher energy density for AC. For CNF, lower ESR is responsible for having higher power density.Both CNF and AC supercapacitor exhibit an excellent charge-discharge stability up to 2500 cycles.