影响锂离子电池安全性的因素

锂离子电池的安全性一直是锂离子电池 ,特别是大型锂离子电池研制、生产、使用中的关键性问题 ,通过对锂离子电池的材料、制造工艺以及使用条件等方面的探讨 ,分析影响锂离子二次电池安全性的各种因素     

锂离子电池正极材料的结构设计与改性

正极材料是目前锂离子电池中锂离子的唯一或主要提供者,也是锂离子电池能量密度提高和价格降低的瓶颈.本文在简要介绍几类典型的正极材料结构、性能特点及存在的主要问题后,重点介绍本实验室近年来在正极材料的表面改性和结构设计方面的研究进展.     

锂离子电池安全性能研究

随着锂离子电池能量密度进一步提高,成本进一步降低,其应用领域越来越广泛,特别是最近几年来在电动汽车和储能领域的应用被寄予厚望.然而,锂离子电池的安全性是目前制约其应用领域扩展的主要瓶颈之一.锂离子电池的安全性归根结底取决于锂离子电池材料的热稳定性,本文综述了锂离子电池材料热稳定性的理解和提高方面的最新进展.过充、热箱、...     

下一代能源存储技术及其关键电极材料

由于能源危机与环境问题,全球能源的消耗正逐渐从传统化石能源转向其它清洁高效能源。高效清洁能源的存储是电动汽车和智能电网的关键技术,对新能源、新材料和新能源汽车国家战略新兴产业的发展具有重要意义。锂离子电池是目前广泛应用的一种能源存储器件。电动汽车和智能电网对能量密度、功率密度、循环寿命和成本等方面的要求越来越高,传统的锂离子电池面临巨大挑战,发展下一代能源存储技术迫在眉睫。高能量密度的锂硫电池和锂空气电池,低成本、高安全性的室温钠离子电池受到了越来越多的关注。本文简要总结了近年来锂硫电池、锂空气电池和钠离子电池及其关键电极材料的研究进展,并对这些新型能源存储技术存在的问题和未来的前景做出了分析和展望。     

钠离子混合电容器电极材料的研究进展

钠离子混合电容器(SIHCs)因其资源丰富和价格低廉等优点,同时具有与锂相似的物理化学性质,被认为是最具有发展前景的电化学储能器件之一。通常,SIHCs由高能量密度的阳极和高功率密度的阴极组成,可在钠离子电池和超级电容器之间搭建能量和功率的桥梁。然而,电容型正极材料和电池型负极材料之间的动力学和容量的不平衡问题成为实现其规模化应用的主要瓶颈。本文概述了SIHCs相关的工作原理和各类正、负极材料研究进展,从材料结构的可控制备和改性处理等方面对SIHCs发展趋势进行了重点评述,并讨论了SIHCs发展过程中遇到的主要挑战,最后对该领域在未来的研究方向进行了展望。     

机器学习在设计高性能锂电池正极材料与电解质中的应用

随着大数据和人工智能的发展以及机器学习(ML)与化学学科领域的交叉，ML技术与电池领域的结合激发了更有前途的电池开发方法，尤其在电池材料设计、性能预测、结构优化等方面的应用愈加广泛。应用ML可以有效地加速电池材料的筛选进程并预测锂电池(LBs)的性能，从而推动LBs的发展。本文简要介绍了ML的基本思想及其在LBs领域中几种重要的ML算法，之后讨论了传统模拟计算方法与ML方法各自的误差表现及分析，借此来提高LBs专家对ML方法的理解。其次，重点介绍了ML在电池材料实际开发中的应用，包括正极材料、电解质、材料多尺度模拟及高通量实验(HTE)等方面，借此介绍ML方法在电池领域应用的思想和手段。最后，总结了ML方法在锂电池领域中的研究现状并展望了其应用前景。本综述旨在阐明ML在LBs开发中的应用，并为先进LBs的研究提供借鉴。     

稀土溴化物固态电解质材料在全固态电池中的应用研究进展北大核心CSCD

全固态锂电池具有优异的安全性能和能量密度,有望成为替代传统有机液态锂离子电池的下一代储能产品。固态电解质是决定全固态电池性能的关键材料,其中卤化物固态电解质,尤其是稀土溴化物固态电解质(RE-BSEs)材料近年来在离子电导率(高达mS/cm数量级)和电化学稳定性(1.5~3.4 V vs.Li^(+)/Li)等方面取得了一系列重要的研究进展,具有可期待的应用前景。本文通过对RE-BSEs的发展历程、研究进展、技术瓶颈、发展方向和应用前景等方面进行综述和回顾,给予研究人员在RE-BSEs的合成方法、锂离子传输机理、构效关系和材料设计等方面的参考和启发。稀土是我国乃至世界的重要战略资源,RE-BSEs材料的研究和重要成果明示了稀土元素在固态离子导体和新能源领域的重大价值,因此,做好稀土在该方面的研究工作对能源结构调整、节能减排、碳达峰和碳中和具有重大意义。     

锂离子电池隔膜改性研究进展

锂离子电池作为便携式电子产品、新能源汽车、蓄电设备等产品电源备受关注。锂离子电池由正极、负极、隔膜和电解液四部分组成。隔膜虽然不直接参与锂离子电池中的电化学反应,但是隔膜作为锂离子电池的重要组成部分,其性质在很大程度上影响锂离子电池的性能。目前聚烯烃仍是使用最为广泛和商业化最为成功的锂离子电池隔膜材料,但因其不良的电解液浸润性和热稳定性,降低了锂离子电池的电性能和安全性,因此改性成为改善聚烯烃隔膜材料性能和推广应用的重要途径。本文从聚烯烃材料多层膜结构改性、表面涂覆改性和层层自组装改性三方面总结了近五年聚烯烃隔膜改性研究的最新进展。最后,提出增强聚烯烃隔膜的热稳定性和电化学性能仍是未来研究重点,并对新型隔膜材料进行展望。     

高能量密度的锂离子混合型电容器

锂离子混合型电容器兼有锂离子电池和超级电容器的优点,在电化学储能领域具有广泛的应用前景. 但其产业化仍存在一系列的基础及工艺方面的问题,具体包括器件结构设计、电极材料筛选、预嵌锂工艺和电解液与电极的界面等. 本文结合作者课题组的研究工作介绍了近年来高能量密度的锂离子混合型电容器的研究进展,内容涉及锂离子电容器正/负极材料的筛选、预嵌锂工艺的优化、内并联结构的锂离子电池型超级电容器复合正极组成材料的调控、隔膜的选择、电解液的组成、以及器件的高/低温性能,分析了锂离子电容器的容量衰减机制,探讨了锂离子电池型超级电容器的储能机制,提出了未来对高能量密度的锂离子混合型电容器研究的展望.     

新型超级电容器的研发进展

传统超级电容器受低能量密度的限制,在当今器件研发中需更加关注电极材料结构-组成-性能研究。 本文总结了新型赝电容器的发展历程及其研发过程中存在的挑战与解决措施,着重从胶体离子超级电容器电极材料等新型的电极材料和氧化还原电解质两个方面进行综述。 原位合成的胶体离子超级电容器电极材料比非原位合成的电极材料具有更高的反应活性,并且以近似离子的状态存在,有效增加了电极材料的比容量。 氧化还原电解质的使用在不改变电极材料的前提下,进一步提高了超级电容器的能量密度。 初步介绍了新型锂离子电容器。 锂离子电容器同时使用电池型材料和电容型材料,可提高其能量密度。 依据当前超级电容器的研发现状,未来有望将电池材料和电容器材料结合使用,进而形成电池电容器或电容电池,使其同时具有高的能量密度和功率密度。     

NASICON结构正极材料用于钠离子电池的研究进展

随着二次电池技术的迅速发展,锂离子电池(LIBs)已经成为了当今社会一种重要的储能装置。然而,地壳中锂资源有限、含锂化合物价格昂贵,因此科研工作者正在积极寻找LIBs的替代品。钠离子电池(SIBs)具有与LIBs相似的工作原理,且钠元素在地球上储量更丰富更均匀、价格更低廉,使得SIBs成为了最有希望替代LIBs的新型二次电池体系之一。不过,钠离子半径较大、充放电过程中电极材料的不可逆性更明显等缺点,明显地增加了开发高性能SIBs的难度。因此,寻找具有优异性能的电极材料,成为了当前SIBs研究的难点和重点。钠超离子导体(NASICON)结构材料是一类具有超快钠离子传导能力的化合物,在脱/嵌钠过程中具有离子传导率高、结构稳定等优点,表现出明显的应用潜力。本文将在介绍NASICON材料晶体结构的基础上,重点从过渡金属种类与个数,以及阴离子调控的角度,总结其研究进展,并分析了该类材料面临的主要问题和挑战。     

表面限域掺杂提升高比能正极材料稳定性

Lithium ion batteries (LIBs) have broad applications in a wide variety of a fields pertaining to energy storage devices. In line with the increasing demand in emerging areas such as long-range electric vehicles and smart grids, there is a continuous effort to achieve high energy by maximizing the reversible capacity of electrode materials, particularly cathode materials. However, in recent years, with the continuous enhancement of battery energy density, safety issues have increasingly attracted the attention of researchers, becoming a non-negligible factor in determining whether the electric vehicle industry has a foothold. The key issue in the development of battery systems with high specific energies is the intrinsic instability of the cathode, with the accompanying question of safety. The failure mechanism and stability of high-specific-capacity cathode materials for the next generation of LIBs, including nickel-rich cathodes, high-voltage spinel cathodes, and lithium-rich layered cathodes, have attracted extensive research attention. Systematic studies related to the intrinsic physical and chemical properties of different cathodes are crucial to elucidate the instability mechanisms of positive active materials. Factors that these studies must address include the stability under extended electrochemical cycles with respect to dissolution of metal ions in LiPF₆-based electrolytes due to HF corrosion of the electrode; cation mixing due to the similarity in radius between Li⁺ and Ni²⁺; oxygen evolution when the cathode is charged to a high voltage; the origin of cracks generated during repeated charge/discharge processes arising from the anisotropy of the cell parameters; and electrolyte decomposition when traces of water are present. Regulating the surface nanostructure and bulk crystal lattice of electrode materials is an effective way to meet the demand for cathode materials with high energy density and outstanding stability. Surface modification treatment of positive active materials can slow side reactions and the loss of active material, thereby extending the life of the cathode material and improving the safety of the battery. This review is targeted at the failure mechanisms related to the electrochemical cycle, and a synthetic strategy to ameliorate the properties of cathode surface locations, with the electrochemical performance optimized by accurate surface control. From the perspective of the main stability and safety issues of high-energy cathode materials during the electrochemical cycle, a detailed discussion is presented on the current understanding of the mechanism of performance failure. It is crucial to seek out favorable strategies in response to the failures. Considering the surface structure of the cathode in relation to the stability issue, a newly developed protocol, known as surface-localized doping, which can exist in different states to modify the surface properties of high-energy cathodes, is discussed as a means of ensuring significantly improved stability and safety. Finally, we envision the future challenges and possible research directions related to the stability control of next-generation high-energy cathode materials.     

原子力显微镜在锂离子电池界面研究中的应用

近几年,电动汽车市场的飞速发展对锂离子电池的能量密度和安全性提出了更高的要求. 然而,过去近30年,在应用终端市场的大力推动下,锂离子电池的电极材料、电池结构设计和生产工艺都已经发展得比较成熟,容量提升空间已经比较小,想要进一步提高现有锂离子电池的能量密度,需要对锂离子电池的整个系统和工作原理有更深刻和全面的理解. 存在于锂离子电池电极材料和电解液之间的固态电解质中间相（solid electrolyte interphase,SEI）已被证明是一个影响电池性能的重要因素,目前学术界和产业界对其认识还不是很全面,尤其是高分辨、工况下以及多技术联合的界面表征工作较少见到报道. 原子力显微镜（atomic force microscopy,AFM）通过探测针尖与样品之间的相互作用力,能够在原子尺度上原位表征液态电池界面的形貌以及力学特性,对于电极界面的理解和调控非常重要. 本文作者通过总结近几年AFM在锂离子电池SEI研究的中的应用,并结合本课题组在该领域的工作,对AFM技术在锂离子电池SEI研究中的应用做了总结和展望,对加深锂离子电池界面的理解,以及构建稳定锂电池界面的相关研究有参考意义.     

Rational design on separators and liquid electrolytes for safer lithium-ion batteries

As the energy density of lithium-ion batteries (LIBs) continues to increase,their safety has become a great concern for further practical large-scale applications.One of the ultimate solution of the safety issue is to develop intrinsically safe battery components,where the battery separators and liquid electrolytes are critical for the battery thermal runaway process.In this review,we summarize recent progress in the rational materials design on battery separators and liquid electrolyte towards the goal of improving the safety of LIBs.Also,some strategies for further improving safety of LIBs are also briefly outlooked.     

二硒化钼基材料的制备及其在二次电池中的研究进展

二次电池由于具循环寿命长、成本低廉、绿色环保等优点受到科研工作者的广泛关注,而电极材料对整个电池系统的性能起着至关重要的作用。二硒化钼由于具有独特的层状结构、电导率高、带隙较窄等特点,被认为是储能领域的明日之星。然而,金属硒化物在循环过程中体积变化严重,导致动力学和电化学稳定性较差,限制了其在二次电池中的进一步实际应用。因此,研究者通过调整合成方法、与碳质材料复合、设计独特的结构等手段来缓解金属硒化物电极的稳定性问题。本文综述了二硒化钼材料的制备工艺、复合改性方法及其在二次电池中应用现状,最后对该材料在二次电池中所面临的挑战和应用前景进行了总结。     

镁离子电池正极材料研究进展

镁离子电池(MIBs)因镁资源储量丰富、体积能量密度大、金属镁空气中相对稳定等优势,被认为是具有大规模储能应用潜力的电池体系。然而,镁离子较高的电荷密度和较强的溶剂化作用导致其在正极材料中的可逆脱嵌和固-液界面上的离子扩散相当缓慢,严重影响了MIBs的电化学性能。近年来,人们针对MIBs正极材料开展了大量工作,取得了一定进展,但是还存在不少问题。本文先从MIBs体系的特点出发,阐述其优势和目前所面临的主要挑战,然后从无机正极材料和有机正极材料两方面展开,梳理并总结了各类正极材料的局限性及其解决策略,对优化方法和材料性能间的相关性进行归纳和讨论,为今后进一步发展具有优异电化学性能的MIBs正极材料提供可能的参考。     

高温锂电池氧化物正极材料研究现状与展望

高温锂电池是热电池向中低温度范围的拓展和延伸,在石油、天然气及地热探测等领域有很好的应用前景。相对于具有大比容量和接近纯锂电极电位的锂合金负极材料,正极材料还有不小的发展潜力。因此,正极材料是提升高温锂电池性能的关键材料。而在正极材料中,氧化物材料表现出高电压特性以及高热稳定性,可以推动高温锂电池小型化发展,满足特定条件下的电流电压供给。目前,并没有针对高温锂电池氧化物正极材料的系统性综述。为了促进本领域的快速发展,优化能源结构,本文系统总结了高温锂电池过渡族金属氧化物正极材料的研究进展,包括其物理特性、电化学特性及合成与制备方法,对材料的可利用特性以及不足之处加以说明;进而对氧化物正极材料在高温锂电池领域的应用做出展望。     

高温锂电池氧化物正极材料研究现状与展望

高温锂电池是热电池向中低温度范围的拓展和延伸,在石油、天然气及地热探测等领域有很好的应用前景。相对于具有大比容量和接近纯锂电极电位的锂合金负极材料,正极材料还有不小的发展潜力。因此,正极材料是提升高温锂电池性能的关键材料。而在正极材料中,氧化物材料表现出高电压特性以及高热稳定性,可以推动高温锂电池小型化发展,满足特定条件下的电流电压供给。目前,并没有针对高温锂电池氧化物正极材料的系统性综述。为了促进本领域的快速发展,优化能源结构,本文系统总结了高温锂电池过渡族金属氧化物正极材料的研究进展,包括其物理特性、电化学特性及合成与制备方法,对材料的可利用特性以及不足之处加以说明;进而对氧化物正极材料在高温锂电池领域的应用做出展望。     

锂离子电池正极材料中的极化子现象理论计算研究进展

In addition to their extensive commercial application in electronic devices such as cell phones and laptops, lithium-ion batteries (LIBs) are most suitable to fulfill the energy storage requirements of electric vehicles because of their recognized safety, portability, and high energy density. Cathodes are the most important part of LIBs, and various cathode materials have been widely investigated over the past decades. Polaron formation has been attracting increasing attention in the research of cathode materials, as it limits electron conduction. In particular, polarons are responsible for low electronic conductivity in cathode materials like olivine phosphate. Polaron is a typical crystal defect caused by the integrated motion of lattice distortion and its trapping electrons. Research on the mechanism of polaron formation will provide theoretical guidance for the design of high-electronic-conductivity cathode materials and improvement of the electrochemical performance of LIBs. Theoretical calculation is a direct and important method to study polaron formation in a specific crystal material, because the presence of polarons and their formation mechanisms can be effectively verified through this method. In this article, we first introduce the basic physical concept of polarons and their dynamical model according to the Marcus and Emin-Holstein-Austin-Mott theories. A comparison of the general properties of large and small polarons, summarized in this chapter, reveals that small polaron formation more likely occurs in cathode materials. Moreover, the theoretical characterization, electrical impact, control and challenges of polarons are reviewed. Although a universal necessary and suitable condition for the theoretical characterization of polarons has not yet been found, we still propose three criteria that are proven to be feasible and practical for the theoretical identification of polarons when applied in combination. Experimental characterizations are also introduced briefly for reference, because the comparison with the experiment is suggested to be necessary and mandatory. The electrical impact caused by polarons results in low electronic conductivity, which has been broadly reported in layered, olivine, and spinel cathode materials. Doping can weaken the influence of polarons and, thus, significantly enhance the electronic conductivity, thereby becoming the most prevalent strategy for tuning polarons. Although theoretical calculations have been widely and effectively conducted in the study of polarons, some challenges may still be faced because of the intrinsic shortcomings of the traditional density functional theory, which need to be addressed. Finally, further research on polarons from the perspective of basic theory and practical applications is prospected.     

The development of lithium ion secondary batteries

Lithium ion secondary batteries (LIBs) were successfully developed as battery systems with high volumetric and gravimetric energy densities, which were inherited from lithium secondary batteries (LSBs) with metallic lithium anodes. LSBs have several drawbacks, however, including poor cyclability and quick-charge rejection. The cell reaction in LIB is merely a topochemical one, namely the migration of lithium ions between positive and negative electroces. No chemical changes were observed in the two electrodes or in the electrolytes. This results in little chemical transformation of the active electrode materials and electrolytes, and thus, LIBs can overcome the weaknesses of LSBs; for example, LIBs show excellent cyclability and quick-charge acceptance. Many difficulties, however, were encountered during the course of development, including capacity fade during cycling and safety issues. This article is the story of the development of LIBs and it describes how the difficulties were surmounted.