Advances in supercapacitors: From electrodes materials to energy storage devices

随着绿色储能器件的快速发展,超级电容器作为兼具高比能量与高比功率的优点,在储能领域具有重要发展潜力的新型储能器件,本综述从超级电容器的电极材料出发,详细概括了超级电容器电极材料的发展,包括双电层电容材料、赝电容材料以及双电层/赝电容复合材料;在此基础上,基于固态电解质,深入讨论了近年来全固态超级电容器的典型构型,针对性地总结了提高储能器件储能容量的关键问题。最后,基于电极材料与电解液的研究焦点,对超级电容器的研究提出了未来发展方向。     

Preparation and performance of high-voltage electrolytes for supercapacitors

采用咪唑类离子液体1-乙基-3-甲基咪唑四氟硼酸盐（EMIBF₄）调制了两款耐压电解液并用于大容量圆柱式超级电容器中,考察了电容器的容量、内阻、循环等性能,分析了高压循环过程中电容器的发热行为。结果表明：相比商用耐压电解液,两款自制电解液均能一定程度提高电容器的能量密度,但是由于内阻的增加而引起功率密度有所下降。商用耐压电解液由于表面温升过快,难以在2.85 V及以上电压正常循环,而两款自制电解液均显著减少了表面温升,改善了电容器的高压循环能力。另一方面,降低电流密度可以有效控制超级电容器的表面温升速度,这使得各款电容器都能维持稳定的3 V限压循环,EMIBF₄/AN电解液甚至可以支持3.2 V上限循环,此时基于超级电容器总重量计算的最大能量密度与最大功率密度分别达到8.62 W·h/kg和16.18 kW/kg。     

Research progress on capacitive lithium-ion battery

锂离子电池具有高的能量密度,而超级电容器则以高功率密度和长循环寿命为突出优势。电容型锂离子电池是在锂离子电池的正极中加入部分电容炭材料,在不显著降低能量密度的情况下,大幅度改善锂离子电池的功率特性和循环寿命,从而实现电容与电池技术的融合。本文综述了国内外近年来在电容型锂离子电池领域的最新研究进展,介绍了主要的电容型锂离子电池体系及其性能特点,并对其未来发展方向进行了展望。     

High performance hybrid supercapacitors with LiNi1/3Mn1/3Co1/3O2/activated carbon cathode and activated carbon anode

Hybrid supercapacitors have been studied as a next generation energy storage device that combines the advantages of supercapacitors and batteries. One important challenge of hybrid supercapacitors is to improve energy density (8.9–42 Wh/kg) with maintaining excellent power density (800–7989 W/kg) and cyclability (98.9% after 9000 cycles). Herein, we demonstrate an approach to design hybrid supercapacitors based on LiNi_1/3Mn_1/3Co_1/3O₂ (NMC)/activated carbon (AC) cathode and AC anode (NMC/AC//AC). The NMC/AC//AC hybrid supercapacitors shows outstanding electrochemical performances due to the enhanced energy and power densities. These findings suggest that the NMC/AC cathode is an effective method for high performance hybrid supercapacitors.     

Electrode and electrolyte materials for electrochemical capacitors

Among different electric energy storage technologies electrochemical capacitors are used for energy storage applications when high power delivery or uptake is needed. Their energy and power densities, durability and efficiency are influenced by electrode and electrolyte materials however due to a high cost/performance ratio; their widespread use in energy storage systems has not been attained yet.Thanks to their properties such as high surface area, controllable pore size, low electrical resistance, good polarizability and inertness; activated carbons derived from polymeric precursors are the most used electrode materials in electrochemical capacitors at present. Other electrode materials such as shaped nano-carbons or metal oxides are also investigated as electrode materials in electrochemical capacitors, but only as useful research tools.Most commercially used electrochemical capacitors employ organic electrolytes when offering concomitant high energy and high power densities. The use of aqueous based electrolytes in electrochemical capacitor applications is mainly limited to research purposes as a result of their narrow operating voltage. Recent studies on room temperature ionic liquids to be employed as electrolyte for electrochemical capacitor applications are focused on fine tuning their physical and transport properties in order to bring the energy density of the device closer to that of batteries without compromising the power densities.In this paper a performance analysis, recent progress and the direction of future developments of various types of materials used in the fabrication of electrodes for electrochemical capacitors are presented. The influence of different types of electrolytes on the performance of electrochemical capacitors such as their output voltage and energy/power densities is also discussed.     

Performance of Li-ion secondary batteries in low power,hybrid power supplies

Small, portable electronic devices need power supplies that have long life, high energy efficiency, high energy density, and can deliver short power bursts. Hybrid power sources that combine a high energy density fuel cell, or an energy scavenging device, with a high power secondary battery are of interest in sensors and wireless devices. However, fuel cells with low self-discharge have low power density and have a poor response to transient loads. A low capacity secondary lithium ion cell can provide short burst power needed in a hybrid fuel cell–battery power supply. This paper describes the polarization, cycling, and self-discharge of commercial lithium ion batteries as they would be used in the small, hybrid power source. The performance of 10 Li-ion variations, including organic electrolytes with Li_xV₂O₅ and Li_xMn₂O₄ cathodes and LiPON electrolyte with a LiCoO₂ cathode was evaluated. Electrochemical characterization shows that the vanadium oxide cathode cells perform better than their manganese oxide counterparts in every category. The vanadium oxide cells also show better cycling performance under shallow discharge conditions than LiPON cells at a given current. However, the LiPON cells show significantly lower energy loss due to polarization and self-discharge losses than the vanadium and manganese cells with organic electrolytes.     

Vehicle hybridization with fuel cell,supercapacitors and batteries by sliding mode control

This paper treats the design and control of two hybrid source using supercapacitors, fuel cell, with and without batteries on the DC link. A fuel cell, as a slowest dynamic source in these systems (because of its auxiliaries) acts to supply the permanent energy. The supercapacitors, as a high dynamic and high power density device, compensate the intrinsic limitations in embedded sources and shave transient power peaks. The batteries module, as a high energy density device, operates for supplying energy if limitations of the power and energy sources occur. The load is a single phase DC machine connected directly in the DC bus. Our interest is focused on the comparison of the two structures and on the principles of control of this two hybrid power sources. Some results are presented and discussed.     

Design of high-performance flexible symmetric supercapacitors energized by redox-mediated hydrogels including metal-doped acidic polyelectrolyte

The fabrication of flexible supercapacitors was achieved by employing the novel redox-activated polymer electrolytes comprising poly(vinylphosphonic acid) (PVPA) and nickel nitrate Ni(NO₃)₂, Ni. The hydrogels, PVPA/NiX, were produced in various contents, in which X denotes the doping fraction of Ni in PVPA. The structure, thermal, and morphology of the materials were characterized, and then they were applied for construction of supercapacitors. The performance evaluations of the fabricated devices were carried out by electrochemical impedance spectroscopy, galvanostatic charge-discharge, and cyclic voltammetry experiments. Flexible supercapacitor devices assembled with activated carbon (AC) electrodes and PVPA/NiX hydrogels produced 793 F g⁻¹ specific capacitance with 30 times enhanced capacitance compared with Ni-free system. The energy density of 103.1 Wh kg⁻¹ was yielded from the device at a power density of 500 W kg⁻¹. The supercapacitor demonstrated an excellent performance during 5.000 charge-discharge cycles, while preserving 84% of its initial capacitance. The supercapacitor constructed of 1 × 5 cm dimension, successfully operates the LED after charging at 3 V.     

Advanced cyclic stability and highly efficient different shaped carbonaceous nanostructured electrodes for solid-state energy storage devices

The most reliant storage technologies are batteries and supercapacitors. While supercapacitors are more efficient in terms of faster energy delivery, sustainability, and high capacity retention. In supercapacitors, mostly utilized precursors are least abundant which are toxic and costly, as well as facing structural stability issues during the advanced charging-discharging cycles. So in the present work, we have studied the sustainability and capacity retention profile of shape-dependent carbonaceous materials in terms of cyclic stability. Here, we have prepared an environment-friendly, cost-effective carbon@FeOOH composite series by low-temperature hydrothermal method. The galvanostatic charge-discharge analysis shows a high power density of 5000 W kg^?1 at a current density of 10 A g^?1. The advanced capacity retention up to 92% is seen up to 15,000 cycles and 100% Coulombic efficiency till the last segment (30000^th segment of charging-discharging) of galvanostatic charge-discharge (GCD) for optimized mesoporous carbon@FeOOH (MCF) sample. The symmetric solid-state device comprising MCF electrodes has been fabricated at the laboratory scale. It has been able to glow red LED for 18 min and a panel consisting of 16 LEDs for 5 min. A self-explanatory mechanism has also been proposed for a better understanding of readers.     

High voltage and self-healing zwitterionic double-network hydrogels as electrolyte for zinc-ion hybrid supercapacitor/battery

The hydrogel electrolyte is an important part of safety and development potential in zinc-based energy storage equipment due to its inherent low mechanical strength and voltage decomposition. However, hydrogel electrolytes possess a reduced working life for zinc dendrites growth and a narrow voltage window. In this study, a hydrogel electrolyte prepares by the zwitterionic monomer [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) (MS) and sodium alginate (SA) alleviate these problems. The zwitterionic double-network hydrogel has good mechanical strength, inhibits the growth of zinc dendrites, enhances practicability, greatly increases the voltage window (0–2.4 V), and has self-healing properties to its rich functional groups. The assembled zinc-ion hybrid supercapacitors (ZHSs) have a high-power density of 172.33 W kg^?1 and an energy density of 88.56 Wh·kg^?1 at 0.5 A g^?1. The assembled zinc-ion battery also has good electrochemical performance. Flexible ZHSs and batteries provide power to the timer stably under different bending angles. The zwitterionic double-network hydrogel can be applied to both zinc-based supercapacitors and batteries.     

Synergistic properties of molybdenum disulfide (MoS2) with electro-active materials for high-performance supercapacitors

Hybrids of molybdenum disulfide (MoS₂) are highly applicable in supercapacitors due to their unique morphological aspects and electrochemical characteristics. Numerous variations in composition and synthetic techniques are available for optimal use of electro-active materials in electrode formation. This article reviews the recent advancement of MoS₂ hybrids in supercapacitors. It provides detailed insights on electrochemical and structural properties of supercapacitors like energy density, power density, specific capacitance, cyclic stability, and surface morphology. Furthermore, it also discusses the influence of mass loading and surface morphology on the electrochemical performance of supercapacitors.     

Supercapacitors accumulating energy harvesting from stacked sediment microbial fuel cells and boosting input power for power management systems

Supercapacitors, are commonly connected to the sediment microbial fuel cell (SMFC) and then serves as the input source for the power management system (PMS). To compare and analyze functions of supercapacitors in SMFC energy harvesting, PMSs (PMS I and PMS II) are powered by SMFC stack or charged supercapacitors as the input source. Tests indicate that the charged supercapacitor results in a higher input power and a larger output power. In addition, the overall efficiency of PMSs is rarely affected by the capacitance, but the initial voltage of the supercapacitor. By charging supercapacitors connected in parallel and then discharging them in series, the overall power efficiency of PMS II is increased from 44.33% to 69.52%. In conclusion, supercapacitors firstly storing SMFC energy is beneficial to provide sufficient energy, resulting in an improved PMS performance. Further, these results can be useful and informative to PMS design for efficiently harvesting and utilize MFC energy.     

The choice of noble electrolyte for symmetric polyurethane-graphene composite supercapacitors

Simple, low cost, highly conducting, flexible, lightweight and porous electrodes are prepared using reduced graphene oxide (rGO) for energy storage device applications. Graphene oxide (GO) slurry is prepared using graphite powder through oxidation followed by solvothermal reduction. A simple dip and dry method to fabricate flexible electrodes by depositing GO on the skeleton of foams is reported. These electrodes are chemically reduced to enhance the conductivity and are used as an electrode material to facilitate large surface area and fast ionic diffusion. The state of the art of present work is all the devices studied under open air condition. The electrochemical studies demonstrate that the constructed supercapacitors exhibit a high specific capacitance of 69 F/g in 1 M NaOH electrolyte at 2 mVs⁻¹ scan rate which is significantly high. Also, the devices showed encouraging performance when constructed with different electrolytes, which helps to understand the electrolytic effect and to choose the best electrolyte for the high performance of supercapacitors.     

Applications of supercapacitors

与传统二次电池相比,超级电容器因其具有寿命长、功率密度大等特点,能够满足电动汽车、电子存储设备、家用电气、航天航空设备等一些应用领域对高功率储能装置的需求,因此自其问世以来,这种储能器件的应用便急速扩展。本文对双电层电容器和混合型超级电容器进行了简单介绍,并对其应用进行综述。     

Chelate complexes with boron as lithium salts for lithium battery electrolytes

The electrolytic conductivity and charge–discharge characteristics of lithium electrodes are examined in propylene carbonate (PC)- and ethylene carbonate (EC)-based binary solvent electrolytes containing lithium bis[1,2-benzenediolato(2-)-O,O′]borate (LBBB), lithium bis[2,3-naphthalenediolato(2-)-O,O′]borate (LBNB) and lithium bis[2,2′-biphenyldiolato(2-)-O,O′]borate (LBBPB). The LBBPB exhibits high thermal and electrochemical stability compared with LBBB and LBNB. Conductivities in PC-THF and EC-THF binary solvent electrolytes at XTHF (mole fraction of tetrahydrofuran, THF)=0.5 containing 0.5 M LBBB and LBNB are nearly equal to that in 0.5 M LiCF₃SO₃ electrolyte as a typical lithium battery electrolyte. The conductivity in 0.3 M LBBPB/PC-DME (DME: 1,2-dimethoxyethane) electrolyte is fairly low compared with that in other electrolytes. The energy density with the LBNB electrolyte is higher than that with LBBB or LBBPB electrolyte. In general, lithium cycling efficiencies in THF-based LBBB and LBNB electrolytes become higher than those in DME-based electrolytes. The 0.5 M LBNB/PC-THF electrolyte is a moderately rechargeable lithium battery electrolyte. The 0.3 M LBBPB/PC-DME equimolar solvent electrolyte displays the highest cycling efficiency, viz., >70%, at a high range of cycle number.     

超级电容器国内外应用现状研究

近年来超级电容器因功率密度高、充电时间短、使用寿命长等优点,逐渐成为工业、交通以及能源行业等众多领域的热门储能器件。对超级电容器的原理、类别及特点进行简要介绍,并详细介绍了国内外超级电容器产业的发展和应用现状。对超级电容器在应用中存在的问题进行了简要分析。     

Research progress of inorganic solid electrolytes in foundmental and application field

全固态锂电池由于具有安全性高、循环寿命长、能量密度高等特点,在高安全化学电源领域具有非常好的应用前景。固体电解质材料是全固态锂电池的核心,迄今被研究过的锂离子固体电解质体系很多,但性能好的材料较少。NASICON型结构氧化物、石榴石型结构氧化物、硫化物体系等锂离子固体电解质在室温下具备高离子电导率,是最具有应用前景的3类锂离子固体电解质材料。本文针对近年来国内外在这3类固体电解质材料方面的研究现状,主要从其结构特征、制备方法、改性研究等方面进行了简要的概括,归纳出各种电解质材料的特点,最后阐述锂离子固体电解质材料应用于全固态锂电池中面临的挑战和发展的前景。     

Butylene sulfite as a film-forming additive to propylene carbonate-based electrolytes for lithium ion batteries

Butylene sulfite (BS) has been synthesized and the BS-based electrolytes containing different lithium salt are evaluated with differential scanning calorimetry (DSC) and alternating current impedance spectroscopy. These electrolytes exhibit high thermal stability and good electrochemical properties. BS has been investigated as a new film-forming additive to propylene carbonate (PC)-based electrolytes for use in lithium ion batteries. Even in small additive amounts (5 vol.%) BS can effectively suppress the co-intercalation of PC with solvation lithium ion into graphite. The formation of a stable passivating film on the graphite surface is believed to be the reason for the improved cell performance. The LUMO energy and the total energy of the sulfite molecules are higher than that of the carbonate ones. It is clearly indicated that the sulfite molecules can easily accept electrons and bears a high reaction activity. The lithium-oxy-sulfite film (Li₂SO₃ and ROSO₂Li) resulting from the reductive decomposition of BS is studied by the density functional theory (DFT) calculations. In addition, the PC-BS electrolytes are characterized by a high oxidation stability allowing the cycling of a LiMn_1.99Ce_0.01O₄ and LiFePO₄-C cathodes with good reversibility.     

Electrochemical performance of lithium ion capacitors using high-capacitance Li2NiO2/AC as the negative electrode

兼具锂离子电池高能量密度和双电层电容器高功率特性的锂离子电容器成为了现今超级电容器性能提升的重点发展方向。本工作以高富锂金属氧化物Li2NiO2为锂离子电容器用负极锂源,将其与活性物复合组成正极电极,并制备出“无金属锂片”预嵌锂过程的300 F锂离子电容器,考察了金属氧化物Li2NiO2的理化性能与电化学特性、不同Li2NiO2添加量对锂离子电容器样品的电化学性能影响。结果表明,Li2NiO2材料具有398 mA·h/g的首次不可逆容量,首次放电不可逆率为94.8%。添加15%～20% Li2NiO2的样品在10 A电流下具有大于75%倍率特性以及91%的容量保持率。当Li2NiO2添加量为20%时,样品在1 A条件下具有400 F的容量,15.5 W·h/kg的能量密度以及11.3 kW/kg的功率密度,是一种制备工艺简单、性能优异的新型锂离子电容器。     

Hybrid electrodes composed of electroactive polymer and metal hexacyanoferrates in aprotic electrolytes

In this work hybrid materials composed of electroactive polymer poly(3,4-ethylenedioxythiophene) (pEDOT) and metal hexacyanoferrates (Mehcf) (Me = Fe, Co, Ni) were tested in ethylene carbonate (EC):propylene carbonate (PC) electrolytes containing 0.5 M KPF₆ or 0.5 M LiPF₆ salts. The hybrid materials pEDOT/Mehcf were examined by using: cyclic voltammetry (CVA), potentiometry and impedance spectroscopy (IS). The materials pEDOT/Mehcf exhibit electrode activity, good stability and high electrical capacity in tested nonaqueous electrolytes and they are considered to be suitable active materials for supercapacitors or for positive electrode of secondary cell with lithium and potassium salts. Contrary to the solid Prussian Blue “PB” analogues, hybrid pEDOT/Cohcf electrodes work with good efficiency in contact with nonaqueous electrolyte containing lithium salts.