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。     

C,N co-doped Co3O4 hollow spheres prepared via hydrothermal reaction for improved electrochemical activity

Superior electrode materials play a key role on the electrochemical performance for the lithium-ion batteries and supercapacitors. The Co₃O₄-based materials are promising electrode materials due to their high specific capacity and energy density. However, the poor cycle performance limits their applications during the process of the commercialization for the lithium-ion batteries and supercapacitors. Because of the poor cycle stability, C, N co-doped Co₃O₄ hollow spheres are successfully prepared and used as electrode materials for the lithium-ion batteries and supercapacitors. Via the C, N co-doping process, the electronic conductivity is greatly improved. Moreover, the hollow structure could ensure the structural stability during the electrochemical process. As a result, the cycle performance and specific capacity are greatly improved when the C, N co-doped Co₃O₄ composites are used as electrode materials for the lithium-ion batteries and supercapacitors.     

Saft lithium-ion energy and power storage technology

Since they were first introduced in the early 1990s, lithium-ion batteries have enjoyed unprecedented growth and success in the consumer marketplace. Combining excellent performance with affordability, they have become the product of choice for portable computers and cellular phones. Building on the same energy and life cycle attributes which marked their consumer market success, but adding new high power storage capability, lithium-ion technology is now poised to play a similar role in the transportation sector. With major programmes in both high capacity and high power lithium-ion technology, Saft has developed a family of products which can address the power and energy storage needs for vehicles, utilities, aviation, satellites, and other applications where light weight, long life, and excellent energy or power storage capabilities are needed. Although further development and refinements are underway, Saft has made a major commitment to bring this technology to the market with the establishment of a major pilot and research facility in Bordeaux France. This paper discusses the performance of this family of products and their potential applications.     

Electrical and electrochemical performance characteristics of large capacity lithium-ion cells

We are currently evaluating large capacity (20–40 Ah) Bluestar (cylindrical) and Yardney (prismatic) lithium-ion cells for their electrical and electrochemical performance characteristics at different temperatures. The cell resistances were nearly constant from room temperature down to −20°C, but increased by over 10 times at −40°C. The specific energies and powers, as well as the energy densities and power densities are high and did not reach a plateau even at the highest discharge rates tested. For example, the prismatic lithium-ion cells gave close to 280 Wh dm⁻³ from a 4 A discharge and 249 Wh dm⁻³ at 20 A, both at room temperature. For the same current range the specific energy values were 102 Wh kg⁻¹ and 91 Wh kg⁻¹. Cycle life and other electrical and electrochemical properties of the cells will be presented.     

Research progress of metal oxides as anode materials for lithium ion capacitors

锂离子电容器是一种介于超级电容器和锂离子电池之间的新型储能器件,具有高能量密度、高功率密度以及长循环寿命等优点,在电动汽车、轨道交通、智能电网、可移动电子设备等领域具有非常广泛的应用前景。金属氧化物具有脱/嵌锂能力优异,理论比容量普遍较高,而且自然资源丰富、环境友好的优点,是一类理想的锂离子电容器负极材料,但电子导电率不高,脱/嵌锂过程中不可逆体积畸变较大,影响了其商业化的应用。本文综述了金属氧化物负极材料的制备方法,并分析了其作为锂离子电容器负极材料的电化学性能与优缺点,最后展望了金属氧化物负极材料未来的发展方向。     

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。     

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.     

Energy-storage technologies and electricity generation

As the contribution of electricity generated from renewable sources (wind, wave and solar) grows, the inherent intermittency of supply from such generating technologies must be addressed by a step-change in energy storage. Furthermore, the continuously developing demands of contemporary applications require the design of versatile energy-storage/power supply systems offering wide ranges of power density and energy density. As no single energy-storage technology has this capability, systems will comprise combinations of technologies such as electrochemical supercapacitors, flow batteries, lithium-ion batteries, superconducting magnetic energy storage (SMES) and kinetic energy storage. The evolution of the electrochemical supercapacitor is largely dependent on the development of optimised electrode materials (tailored to the chosen electrolyte) and electrolytes. Similarly, the development of lithium-ion battery technology requires fundamental research in materials science aimed at delivering new electrodes and electrolytes. Lithium-ion technology has significant potential, and a step-change is required in order to promote the technology from the portable electronics market into high-duty applications. Flow-battery development is largely concerned with safety and operability. However, opportunities exist to improve electrode technology yielding larger power densities. The main barriers to overcome with regard to the development of SMES technology are those related to high-temperature superconductors in terms of their granular, anisotropic nature. Materials development is essential for the successful evolution of flywheel technology. Given the appropriate research effort, the key scientific advances required in order to successfully develop energy-storage technologies generally represent realistic goals that may be achieved by 2050.     

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.     

Investigation of aging mechanisms of high power Li-ion cells used for hybrid electric vehicles

High power lithium-ion batteries need to exhibit long service life to meet targets of automotive applications. This article describes the deep investigation of the so-called VL6P cells, high power lithium-ion cells mass produced by Johnson Controls - Saft (JC-S), in order to understand the root causes of their aging. Cells aged by calendar and cycle life are investigated here compared to fresh cells. Among the results of the different analyses, the most significant is that more active lithium is detected in negative electrode after aging. This tends to indicate that effect of aging is due to increase of positive electrode limitation. Results of this investigation will allow JC-S to continue to improve life of the lithium-ion cells.     

Research progress on biomass-derived carbon electrode materials for electrochemical energy storage and conversion technologies

Electrochemical energy technologies such as fuel cells, supercapacitors, and batteries are some of the most suitable energy storage and conversion devices to meet our needs proving the future generation’s equitable opportunity to meet their own needs. For this purpose, an earth-abundant precursor such as biomass is the best candidate for the synthesis of the next generation of low-cost and green electrode materials. This review summarizes the most recent progress in biomass-derived carbons for use in fuel cells, supercapacitors and lithium-ion batteries, the physical-chemical properties, desired features, performances, and limitations for electrochemical energy technologies. Several thermochemical treatments such as chemical activation, template methods, doping and hydrothermal treatments have been reviewed. Finally, we provide the reader with comprehensive information of the challenges, future research efforts, advantages, limitations and opportunities which will be a fundamental insight for the future design of biomass-derived carbon electrode materials for electrochemical storage and conversion systems.     

Recent progress in the application of carbon materials to supercapacitors and lead-carbon batteries

新型炭材料是电化学储能领域中非常重要的一类储能材料,目前广泛应用于各种电化学储能器件.本文综述了具有电容特性的高比表面积炭材料在超级电容器与铅炭电池中的应用.采用不同的方法合成具有高比表面积的新型炭材料作为超级电容器电极材料,能够得到较高的比容量.适量高比表面积的炭材料应用于铅酸电池负极,形成铅炭电池,极大地提高了电池的储能特性.论文最后探讨了新型炭材料在超电容以及铅炭电池中应用的发展方向.     

Differential pulse effects of solid electrolyte interface formation for improving performance on high-power lithium ion battery

Solid electrolyte interface (SEI) formation is a key that utilizes to protect the structure of graphite anode and enhances the redox stability of lithium-ion batteries before entering the market. The effect of SEI formation applies a differential pulse (DP) and constant current (CC) charging on charge-discharge performance and cycling behavior into brand new commercial lithium ion batteries is investigated. The morphologies and electrochemical properties on the anode surface are also inspected by employing SEM and EDS. The electrochemical impedance spectra of the anode electrode in both charging protocols shows that the interfacial resistance on graphite anodes whose SEI layer formed by DP charging is smaller than that of CC charging. Moreover, the cycle life result shows that the DP charging SEI formation is more helpful in increasing the long-term stability and maintaining the capacity of batteries even under high power rate charge-discharge cycling. The DP charging method can provide a SEI layer with ameliorated properties to improve the performance of lithium ion batteries.     

金属有机框架及其衍生金属氧化物在锂和钠离子电池中的应用

高性能锂和钠离子电池是未来便携电子设备、电动汽车和大规模储能电站的重要组成部分,受到了各行业的广泛关注。目前商用的锂离子电池和研发中的钠离子电池都面临着一些技术瓶颈,主要表现为能量密度低、充放电慢等,导致无法满足市场的需求。具有独特结构、高比表面积的金属有机框架及其衍生金属氧化物可作为电化学储能器件新型电极材料,满足高性能锂和钠离子电池的要求。本文综述了近年来金属有机框架及其衍生金属氧化物作为锂和钠离子电池电极材料的研究进展,同时指出了金属有机框架及其衍生金属氧化物在实际应用中的不足及未来可能的一些改进措施。     

An overview of positive-electrode materials for advanced lithium-ion batteries

Positive-electrode materials for lithium and lithium-ion batteries are briefly reviewed in chronological order. Emphasis is given to lithium insertion materials and their background relating to the “birth” of lithium-ion battery. Current lithium-ion batteries consisting of LiCoO₂ and graphite are approaching a critical limit in energy densities, and new innovating materials are needed in order to continue the advance of lithium-ion batteries. In particular, the recent trends on material researches for advanced lithium-ion batteries, such as layered lithium manganese oxides, lithium transition metal phosphates, and lithium nickel manganese oxides with or without cobalt, are described. Trials on new applications of lithium insertion materials for high-power lithium-ion batteries as well as hybrid capacitors leading for 12 V lead-free accumulators are also highlighted.     

A hybrid PEMFC/supercapacitor device with high energy and power densities based on reduced graphene oxide/Nafion/Pt electrode

Proton exchange membrane fuel cells (PEMFCs) possess high energy and low power densities, while supercapacitors are characterized by high power and low energy densities. A hybrid PEMFC/supercapacitor device (HPSD) with high energy and power densities was proposed and fabricated for the first time using a reduced graphene oxide/Nafion/Pt electrode in this study. The reduced graphene oxide (rGO) was a capacitive material, and Pt was used as the electrocatalyst. Nafion ionomers adsorbed onto the rGO sheets surface and connected the rGO sheets and the electrolyte (Nafion membrane), thus increasing the utilization rate and specific capacitance of rGO. During the half-cell tests, the rGO/Nafion/Pt electrode exhibited better pulse discharge and galvanostatic discharge performance than the conventional Nafion/Pt electrode. Due to the unique synergy of electrochemical reaction current and capacitance current during the discharge process, the HPSD exhibited a higher power density (26.2 kW kg⁻¹) than the PEMFC (23.9 kW kg⁻¹). The energy density (12.7 kWh kg⁻¹) exhibited by HPSD was close to that of the PEMFC (13.5 kWh kg⁻¹). Therefore, the concept of HPSD is to create a new method for developing next-generation electrochemical devices with high energy and power densities.     

All-solid-state lithium-ion batteries:State-of-the-art development and perspective

现有电化学储能锂离子电池系统采用液体电解质,易泄露,易腐蚀,服役寿命短,具有安全隐患.薄膜型全固态锂电池,大容量聚合物全固态锂电池和大容量无机全固态锂电池是一类以非可燃性固体电解质取代传统锂离子电池中液态电解质,锂离子通过在正负极间嵌入-脱出并与电子发生电荷交换后实现电能与化学能转换的新型高安全性锂二次电池.作者综述了各种全固态锂电池的研究和开发现状,包括固态锂电池的构造,工作原理和性能特征,锂离子固体电解质材料与电极/电解质界面调控,固态整电池技术等方面,提出并详细分析了该技术面临的主要科学与技术问题,最后指出了全固态锂电池技术未来的发展趋势.     

Solar photovoltaic charging of lithium-ion batteries

Solar photovoltaic (PV) charging of batteries was tested by using high efficiency crystalline and amorphous silicon PV modules to recharge lithium-ion battery modules. This testing was performed as a proof of concept for solar PV charging of batteries for electrically powered vehicles. The iron phosphate type lithium-ion batteries were safely charged to their maximum capacity and the thermal hazards associated with overcharging were avoided by the self-regulating design of the solar charging system. The solar energy to battery charge conversion efficiency reached 14.5%, including a PV system efficiency of nearly 15%, and a battery charging efficiency of approximately 100%. This high system efficiency was achieved by directly charging the battery from the PV system with no intervening electronics, and matching the PV maximum power point voltage to the battery charging voltage at the desired maximum state of charge for the battery. It is envisioned that individual homeowners could charge electric and extended-range electric vehicles from residential, roof-mounted solar arrays, and thus power their daily commuting with clean, renewable solar energy.     

LiFePO4正极水性粘结剂的研究进展

磷酸铁锂（LiFePO4）具有安全性好、价格低廉以及环境友好等优点,是当前锂离子动力电池的主流正极材料。粘结剂是锂离子电池电极的重要非活性成分,其性能直接影响电池的电化学性能。本文综述了近年来不同水性粘结剂在LiFePO4正极材料中的研究进展,指出了现阶段存在的问题,并对水性粘结剂的应用前景进行了展望。     

Anthraquinone modified carbon fabric supercapacitors with improved energy and power densities

Supercapacitors with improved energy and power densities have been constructed with anthraquinone modified carbon fabric (Spectracarb 2225) as the negative electrode and unmodified carbon fabric as the positive electrode. A Nafion separator and 1 M sulfuric acid electrolyte were employed. The performances of the supercapacitors were characterized by cyclic voltammetry and constant current discharging. Use of the anthraquinone modified electrode as the negative electrode (anode during discharge) in the supercapacitor provides 40% higher average capacitance, 56–86% higher energy density, and improved power duration.