Rechargeable lithium sulfide electrode for a polymer tin/sulfur lithium-ion battery

In this work we investigate the electrochemical behavior of a new type of carbon-lithium sulfide composite electrode. Results based on cyclic voltammetry, charge (lithium removal)-discharge (lithium acceptance) demonstrate that this electrode has a good performance in terms of reversibility, cycle life and coulombic efficiency. XRD analysis performed in situ in a lithium cell shows that lithium sulfide can be converted into sulfur during charge and re-converted back into sulfide during the following discharge process. We also show that this electrochemical process can be efficiently carried out in polymer electrolyte lithium cells and thus, that the Li₂S-C composite can be successfully used as cathode for the development of novel types of rechargeable lithium-ion sulfur batteries where the reactive and unsafe lithium metal anode is replaced by a reliable, high capacity tin-carbon composite and the unstable organic electrolyte solution is replaced by a composite gel polymer membrane that is safe, highly conductive and able to control dendrite growth across the cell. This new Sn-C/Li₂S polymer battery operates with a capacity of 600 mAh g⁻¹ and with an average voltage of 2 V, this leading to a value of energy density amounting to 1200 Wh kg⁻¹.     

Recent progress in electrode materials for aqueous lithium-ion batteries

水系锂离子电池是以水溶液为电解质的二次电池,它克服了传统有机体系电池电解液昂贵,有毒,易燃,离子电导率低,制作成本高等缺点,成为继风能,太阳能后最具发展潜力的绿色能源之一.本文归纳了近年来国内外水系锂离子电池正负极材料的研究进展,介绍了各种电极材料存在的主要问题(如电极材料在电解液中的溶解,电解液中质子活性大导致电极材料发生副反应等)以及改性方法,并提出对电极材料进行修饰是水系锂离子电池未来的发展趋势.     

Review on heat generation theory model of lithium-ion battery

本文根据近年来锂离子电池产热特性方面的研究,详细阐述了锂离子电池产热的基本原理,并总结了国内外锂离子电池产热模型的研究现状。重点针对电化学-热耦合模型、电-热耦合模型以及热滥用模型进行了详细综述,并在此基础上对锂离子电池热效应的研究和产热模型的建立进行了展望。     

5kW锂电池模组BMS的研究与开发

设计了以MSP430为控制核心的用于5 k W锂电池管理系统(BMS).建立了关于电池荷电状态的模型,在实际估计中,采用开路电压和按时积分相结合的方法且有较高的精度;采取电池均衡充电的方案,补偿了电池容量的差异性,进而使得电池组的使用寿命延长.电池荷电状态估算的改进方案解决了按时计量法无法确定初始荷电状态、难以精准测得库仑效率等问题,确保了电池管理系统处于稳定工作状态.该系统具有抗干扰能力极强、硬件电路可靠、且十分经济的特点.经过实验验证,利用该系统进行SOC剩余容量估计的结果较为精确.     

A review on lithium iron phosphate cathode materials

目前全球高动力锂离子电池系统的发展主要集中在锂锰电池,锂钴镍锰电池以及锂铁电池,其中磷酸亚铁锂材料具有高电容量,高放电功率,极佳的长循环寿命以及良好的热稳定性与高温性能等优点,已成为动力锂离子电池首选的高安全性正极材料.然而,磷酸亚铁锂材料在工业化量产时,必须解决电池芯加工性差及材料一致性不佳等问题,作者曾结合多项新颖观念与技术于磷酸亚铁锂材料制做过程,在粉体表面涂布碳层,在晶体内部掺杂金属,分别改善材料电导率与锂离子扩散速度以及有效地控制碳含量,粉体比表面积,碳层均匀性,粒径大小与分布,制备出高质量磷酸亚铁锂产品.该文将回顾并探讨上述研发工作的一些重要结果.     

Research progress of electrode suspensions of lithium-ion flow batteries

锂离子液流电池将锂离子电池的工作原理与传统液流电池的结构特点相结合,是一种正处于基础技术开发阶段的新型电化学储能电池技术,具有输出功率和储能容量彼此独立、成本较低等特点,适用于未来电网储能领域。电极悬浮液作为实现锂离子液流电池充放电功能的主体材料,其导电性能和流动性能是影响锂离子液流电池倍率特性和能量密度的重要因素。论文结合实验数据对该方向面临的主要技术问题及研究重点进行了分析,认为电极悬浮液的研究需要从导电机理、质量比容量、流变性能等方面进一步深入研究,并建立标准评价体系。     

Improvement of flexible lithium battery shelf life by pre-discharging

Poly (methyl methacrylate) (PMMA)-based gel electrolyte has been used in flexible lithium batteries. These batteries are flexible and less than 0.5 mm thick, which make them suitable as power sources for smart cards and radio frequency identification (RFID) tags. We investigated the electrochemical properties of flexible lithium batteries using an impedance analyzer and potentiostat/galvanostat to evaluate the electrical capacities. To prevent the formation of gas by decomposition of electrolyte solvent, the batteries had to be pre-discharged about 5% of theoretical MnO₂ capacity. Of the three kinds of pre-discharging methods, especially, battery two-step pre-discharging method was performed showed the best electrical properties after storage at 60 °C for 60 days.     

The effects of current density and amount of discharge on dendrite formation in the lithium powder anode electrode

A compacted lithium powder anode was used to improve the demerits of dendrite formation of lithium metal. Dendrite formation of lithium metal was restrained to use compacted lithium powder anode under a specific amount of discharge and the current density. In this study, the amount of discharge and the current density which suppress dendrite formation at the surface of a lithium powder electrode were investigated on an experimental basis. Discharge/charge reactions were accomplished on various values of the amount of discharge and current density by using beaker cells. It was analyzed by SEM images whether dendrite was formed or not on the surface of lithium powder electrode. From the various experiments, the relationship between current density and total amount of discharge was deduced as a simple mathematical model. From the model, the critical condition of total amount of discharge for dendrite formation in Li-powder electrode was increased from 0.1 mA cm⁻² to 1 mA cm⁻² current density. However, the critical condition of total amount of discharge was decreased over 1 mA cm⁻². Using the model, the condition whether dendrite formed or not on the Li-powder anode could be estimated.     

Application of lithium battery with mobile container energy system

锂电池一体化箱式移动电源系统主要应用于新能源较为丰富,供电电网薄弱,供电质量要求较高,占地面积有限和多种突发临时性供电需求等地区.该电源系统由电池组,电池管理系统(BMS),双向变流器(PCS),能量管理系统(EMS)及智能辅助系统组成.通过对系统功能单元的构成,各部分功能特性以及关键技术突破三方面进行讨论,在此基础上展望一体化箱式移动电源系统的发展方向和应用前景,为该类型电源系统的创新和推广提供借鉴.     

Analysis for the applications of lithium titanate battery in the MW-class energy storage systems

相对于传统型的锂离子电池,钛酸锂电池具有充放电响应速度快、倍率特性好、寿命长等优点,但钛酸锂电池单位容量的成本较高。本文从储能系统应用需求层面分析典型功率型储能系统对电池倍率和容量的要求,结合钛酸锂电池的特点,得出高倍率的钛酸锂电池应用于功率型储能系统相对于能量型锂电池,可以大幅度减少电池配置数量的结论,因此可发挥钛酸锂电池的竞争优势。     

Physicochemical properties of lithium iron phosphate‐carbon as lithium polymer battery cathodes

Lithium iron phosphate‐carbon (LiFePO₄/multiwalled carbon nanotubes (MWCNTs)) composite cathode materials were prepared by a hydrothermal method. In this study, we used MWCNTs as conductive additive. Poly (vinylidene fluoride‐co‐hexafluoropropylene)‐based solid polymer electrolyte (SPE) was applied. The structural and morphological performance of LiFePO₄/MWCNTs cathode materials was investigated by X‐ray diffraction and scanning electron microscopy/mapping. The electrochemical properties of Li/SPE/LiFePO₄‐MWCNTs coin‐type polymer batteries were analyzed by cyclic voltammetry, ac impedance and galvanostatic charge/discharge tests. Li/SPE/LiFePO₄‐MWCNTs polymer battery with 5 wt % MWCNTs demonstrates the highest discharge capacity and stable cyclability at room temperature. It is indicated that LiFePO₄‐MWCNTs can be used as the cathode materials for lithium polymer batteries. Copyright © 2011 John Wiley & Sons, Ltd.     

Fundamental scientific aspects of lithium ion batteries(Ⅺ)--Lithium air and lithium sulfur batteries

提高能量密度是可充放锂电池研发最重要的目标.近年来,锂硫电池与锂空气电池由于具有高的理论能量密度而受到广泛关注,这两种电池仍然面临较多的科学与技术问题,处于电池开发早期研究阶段.在本文中,重点介绍了锂空气电池的基本工作原理,基本结构组成,所面临的问题和两种特殊体系的锂空气电池, 同时简要介绍了锂硫电池.     

热电池电极材料的研究现状及展望

锂系热电池因具有激活时间短、放电时间长、高比能量和高比功率等特点成为热电池的主导产品。目前对锂系热电池的研究主要集中在电极材料和电解质上,很少有系统综述锂系热电池电极材料的相关文献。本文着重阐述了锂系热电池的阳极材料和阴极材料(硫化物、氧化物和氯化物)的研究现状,并对其未来的发展方向提出了展望。     

基于实时内阻测试的锂电池自适应电流充电策略

为降低电动汽车锂离子电池的充电损耗,提出了一种基于实时内阻测试的锂电池自适应电流充电策略。针对该充电策略中电池的实时内阻测试和最优电流集的求解问题,提出了一种电化学阻抗谱(EIS)检测法和随机进化算法。通过在MATLAB/Simulink中进行仿真实验,验证了算法的可行性。在不改变充电时间的情况下,文章所提出的充电策略比传统的恒流充电方法的减损效果更加显著。     

In situ measurement of lithium mass transfer during charging and discharging of a Ni–Sn alloy electrode

The charging (lithiation) and discharging (delithiation) of a Ni–Sn alloy electrode was examined by means of holographic interferometry and laser scanning confocal microscopy (LSCM). The developing concentration profile of Li⁺ ion during discharging (delithiation) of the Ni–Sn alloy electrode agreed reasonably well with the prediction based on transient diffusion theory, indicating that the cell configuration successfully suppressed natural convection due to the electrochemical reaction. The morphological variation of Ni–Sn alloy electrode during charge/discharge cycle could be observed very clearly by in situ LSCM. It was found that the contraction of active material during the discharge (delithiation) initiates cracks in the Ni–Sn alloy electrode.     

XRD evidence of macroscopic composition inhomogeneities in the graphite–lithium electrode

In situ and ex situ X-ray diffraction (XRD) measurements were carried out on lithiated graphite electrodes at different states of charge. Data were collected from both sides of electrode. We found macroscopic inhomogeneities in the lithium concentration along the electrode thickness even when the electrode was allowed to rest for 24 h. The electrode side facing the lithium counter electrode in the coin type half-cell displays higher lithium concentration as compared to the side opposed to the XRD window. Residual stage 2 compound is found in the supposedly fully lithiated and fully delithiated electrode. It seems that the differences in the chemical potential between stage 2 and stage 1 is too small to average the lithium composition through chemical diffusion at ambient temperature in reasonable times.     

Modelling the thermal behaviour of a lithium-ion battery during charge

A method for modelling the thermal behaviour of a lithium-ion battery (LIB) during charge is presented. The effect of charge conditions on the thermal behaviour is examined by means of the finite element method. A comparison of the experimental charge curves with the modelling results validates the two-dimensional modelling of the potential and current density distribution on the electrodes of an LIB as a function of charge time during constant-current charge followed by constant-voltage charge. The heat generation rates as a function of the charge time and the position on the electrodes are calculated to predict the temperature distributions of the LIB based on the modelling results for potential and current density distributions. The temperature distributions obtained from the modelling are in good agreement with the experimental measurements.     

In situ X-ray diffraction studies of a graphite-based Li-ion battery negative electrode

Lithium-graphite intercalation compounds were synthesised in an electrochemical cell by the application of a series of current pulses, during which non-equilibrium distributions of intercalation phases were created in the graphite. The phase formation and subsequent interconversion were studied by a combination of chronopotentiometry and in situ X-ray diffraction.     

Effect of electrode physical and chemical properties on lithium‐ion battery performance

The effect of physical and chemical properties on the performance of both positive and negative electrodes is studied for lithium‐ion (Li‐ion) batteries. These properties include the lithium diffusivity in the active electrode material, the electrical conductivity of the electrode, and the reaction rate constant at electrode active sites. The specific energy and power of the cells are determined at various discharge rates for electrodes with different properties. In addition, this study is conducted across various cell design cases. The results reveal that at moderate discharge rates, lithium diffusivity in the active negative‐electrode material has the highest impact on cell performance. The specific energy and power of the cell are improved ~11% by increasing the lithium diffusivity in the active negative‐electrode material by one order of magnitude. Around 4% improvement in the cell performance is achieved by increasing the reaction rate constant at the active sites of either electrodes by one order of magnitude. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of SnO2/C anode for lithium ion battery by a reflux-assisted hydrothermal method

以氯化亚锡(SnCl₂·2H₂O)及聚乙烯吡咯烷酮(polyvinylpyrrolidone,PVP)为原料,通过回流辅助水热法制备了SnO₂/C复合材料并将其用作锂离子电池负极材料.采用X射线衍射仪(XRD),扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析材料的结构和形貌;用恒流充放电,交流阻抗(EIS)和循环伏安(CV)对复合材料作为锂离子电池负极材料的电化学性能进行表征.所制备的复合材料中,纳米SnO₂晶粒(5~10 nm)均匀分散在由PVP热解形成的无定形碳中.电化学性能测试表明,该复合材料100次循环后,可逆容量为591.7 mA·h/g,呈现较好的循环性能.优异的电化学性能主要归因于纳米SnO₂颗粒在无定形碳基体中均匀分散及无定形碳对锡颗粒体积变化的有效缓冲.