氟代碳酸乙烯酯在低温锂离子电池液体电解液开发中的应用

锂离子电池的电解液是一种锂盐的有机溶液。目前锂离子电池所采用的有机电解液主要是以碳酸乙烯酯(EC)和碳酸丙烯酯（PC）等为溶剂,以六氟磷酸锂(LiPF6)等锂盐为溶质,并添加适当添加剂所构成。为了改善锂离子电池某些特性,需要添加少量的功能性添加剂。研究开发比较多的锂离子电池添加剂有成膜添加剂、导电添加剂、阻燃添加剂以及耐过充添加剂。本文主要概述氟代碳酸乙烯酯在低温锂离子电池液体电解液开发中的应用，以供开发低温锂离子电池的研究人员参考。     

镍锰酸锂正极材料及其适配性电解液研究最新进展

随着新能源汽车产业的蓬勃发展,对高能量密度动力电池的需求日益迫切。开发高电压正极材料及其适配性电解液,成为下一代高能量密度动力电池的主要研究方向。镍锰酸锂（LiNi_0.5Mn_1.5O₄）材料以其高电压（4.7 V,vs.Li/Li ⁺）、高能量密度（达650 W·h/kg）、资源丰富且价格低廉而受到广泛关注。然而,镍锰酸锂材料在长期的充放电循环过程中,锰从电极材料中溶解,破坏了电极材料的结构,导致电池性能恶化。介绍了镍锰酸锂正极材料及其适配性电解液研究最新进展。指出离子掺杂、表面包覆、复合方法是改善镍锰酸锂电化学性能的有效途径。同时,通过引入成膜添加剂、改变锂盐的种类及浓度、调整主溶剂的种类及比例等方法,可以提高电解液的耐高压性能,提高镍锰酸锂电极与电解液的界面稳定性,也是提升镍锰酸锂电池性能的重要方法。最后提出,适用于锂离子电池的5 V高电压电解液的研发相对滞后,其是制约高电压电池体系应用的主要问题。     

锂离子二次电池电解液研究进展

电解液是锂离子电池的重要组成部分,对电池的许多性能如循环性能、安全性能等有着重要的影响。对近年来国内外涉及电解质盐及有机溶剂的最新研究成果进行了总结和分析。从电解液材料和电解液添加剂的阻燃性能两个角度对锂离子电池材料的安全性能研究进展进行综述,介绍了辅助溶剂的改良和阻燃添加剂的研究状况。     

含硼锂盐添加剂改善己二腈与石墨相容性的研究

腈类溶剂作为锂离子电池高电压电解液体系常用溶剂之一,因其特殊的结构和较高的还原电位,不能在石墨负极表面形成较好的表面钝化膜,从而造成腈类溶剂很难在高电压全电池体系中得以应用。为了解决上述问题,本文使用含硼锂盐双草酸硼酸锂(LiBOB)和二氟草酸硼酸锂(LiDFOB)作为电解液添加剂,通过优化电极/电解液界面膜,解决因己二腈与石墨相容性差而导致电池容量衰减的问题。     

磷酸铁锂电池高温循环性能影响研究

将Li Fe PO4/C锂离子电池分别在25℃(常温)、45℃、55℃下进行0%~100%DOD、1.0 C充/1.0 C放循环测试。结果显示,随温度的升高,电池的循环性能越差。本试验分别比较了电解液、负极材料对不同温度循环性能的影响。电解液中添加高沸点溶剂和抑制Li PF6分解的添加剂、负极使用小粒径中间相碳微球能够提高电池的高温循环性能。     

电解液对锂离子电池性能的影响

锂离子电池的性能与电解液有着密切的关系。电解液的组成主要是:有机溶剂、锂盐、添加剂。本文综述了电解液组成对锂离子电池电化学性能的影响规律;探讨了电解液量对锂离子电池性能的影响以及不同正极材料锂离子电池对电解液量的需求。     

锂离子电池中混合锂盐电解液的应用探讨

锂离子电池因其比容量高、无记忆效应、循环寿命长等优点应用于各个领域中。本文对锂离子电池电解液现状进行了总结,并对混合锂盐电池在未来的发展方向进行梳理,最后对锂盐混合液在锂离子电池中的应用进行了分析,以期促进锂离子电池能够取得更好的发展。     

四氟草酸磷酸锂的制备及应用

四氟草酸磷酸锂主要应用于锂离子电池、锂离子电容器等非水电解液的添加剂或作为新型锂离子电池电解液用盐,能改善电解液的热稳定性和水解稳定性。与六氟磷酸锂相比,四氟草酸磷酸锂具有更好的热稳定性和对水的耐受性,在正极材料表面形成更加稳定的固体电解质界面膜(CEI膜),有效提高电池的高温循环和高温存储性能,因此在高镍、高电压领域有着广泛的应用。本文概述四氟草酸磷酸锂的制备及应用,可供锂离子电池电解液以及锂离子电池开发人员参考。     

锂离子电池低温电解液的研究进展

分析了从溶剂、锂盐和添加剂3个方面对电解液低温性能进行改进技术的研究现状.首先比较了乙烯碳酸酯(EC)基和丙烯碳酸酯(PC)基溶剂的低温性能,并针对这两类有机电解液的电化学和低温特性的改进,详细论述了几种重要的方法和措施,得出有机溶剂优化和添加剂的使用是提高电解液低温性能的有效手段的重要结论.最后指出了锂离子电池电解液低温性能的研究方向和应用前景.     

锂离子二次电池有机电解液研究进展

综述了目前国内外锂离子二次电池用有机电解液的发展状况。从新型导电锂盐的合成,高介电常数有机溶剂的配制,寻找新型电解液添加剂3个方面分析了如何改善和提高有机电解液的性能。     

锂离子电池电解液负极成膜添加剂的研究进展

解决锂离子电池电极材料和电解液相容性的关键是形成稳定且Li⁺可导的固态电解质界面膜(SEI膜),因此,对优质负极成膜添加剂的研究成为锂离子电池研发中的一个热点。本文综述了锂离子电池电解液成膜添加剂的作用原理,具体介绍了各类负极成膜添加剂的研究现状,从成膜反应机理和理论计算方面详述了近几年来负极成膜添加剂的研究进展。分析了所存在的问题主要是如何快速地挑选出更适宜、更高效的成膜添加剂,并指出了成膜添加剂未来的发展趋势为:①研究各添加剂与电解液的反应机理,着重开发对锂离子电池副反应小的负极成膜添加剂;②通过选择两种或两种以上的添加剂的协同作用,以弥补一种添加剂的不足;③提高无机成膜添加剂在电解液中的溶解度。     

The electrochemistry of lithium in ionic liquid/organic diluent mixtures

The electrochemistry of lithium is investigated in a number of electrolytes that consist of a lithium salt dissolved in a combined ionic liquid-organic diluent medium. We find that ethylene carbonate and vinylene carbonate improve electrochemical behaviour, while toluene and tetrahydrofuran are less promising.We also present insights into the electrode passivation caused by these diluents in an ionic liquid electrolyte during lithium cycling. We observe that during lithium cycling those electrolytes with carbonate based diluents are the most able to utilise their previously reported improved lithium ion diffusivities. Conversely, tetrahydrofuran, the most promising diluent of those studied in terms of its known ability to increase lithium ion diffusivity is found not to be as advantageous as a diluent. It appears that the poor electrochemical interfacial properties of the tetrahydrofuran electrolyte prevented the realisation of the benefits of the high solution lithium ion diffusivity.     

Stable interfaces constructed by concentrated ether electrolytes to render robust lithium metal batteries

Lithium metal batteries (LMBs) are highly considered as promising candidates for next-generation energy storage systems.However,routine electrolytes cannot tolerate the high potential at cathodes and low potential at anodes simultaneously,leading to severe interfacial reactions.Herein,a highly concentrated electrolyte (HCE) region trapped in porous carbon coating layer is adopted to form a stable and highly conductive solid electrolyte interphase (SEI) on Li metal surface.The protected Li metal anode can poten-tially match the high-voltage cathode in ester electrolytes.Synergistically,this ingenious design promises high-voltage-resistant interfaces at cathodes and stable SEI with abundance of inorganic components at anodes simultaneously in high-voltage LMBs.The feasibility of this interface-regulation strategy is demonstrated in Li | LiFePO4 batteries,realizing a lifespan twice as long as the routine cells,with a huge capacity retention enhancement from 46.4％ to 88.7％ after 100 cycles.This contribution proof-of-concepts the emerging principles on the formation and regulation of stable electrode/electrolyte inter-faces in the cathode and anode simultaneously towards the next-generation high-energy-density batteries.     

基于LiPF6的锂离子电池电解液的发展现状

近年来随着社会的发展和科技的进步,锂离子电池已成为重要的主流动力电池之一。分别从溶剂和添加剂2个方面综述了基于LiPF6的锂离子电池电解液的发展现状,详细介绍了适用于锂离子电池电解液的溶剂和添加剂,应用于锂离子电池电解液的常用有机溶剂有碳酸酯类、醚类和羧酸酯类有机溶剂,添加剂以其作用目的区分,可分为SEI成膜添加剂、导电添加剂、稳定添加剂、控制水分和游离酸添加剂、抗过充添加剂、阻燃添加剂及浸润性添加剂等;展望了锂离子电池电解液的研究方向。     

The behaviour of graphite, carbon black, and Li4Ti5O12 in LiBOB-based electrolytes

The film formation behaviour of lithium bis(oxalato)borate (LiBOB), a new electrolyte salt for lithium batteries, on graphite, carbon black and lithium titanate is reported. LiBOB is actively involved in the formation of the solid electrolyte interphase (SEI) at the anode. Part of this formation is an irreversible reductive reaction which takes place at potentials of around 1.75 V vs Li/Li⁺ and contributes to the irreversible capacity of anode materials in the first cycle. Carbon black interacts strongly with LiBOB-based electrolytes, which results in strong film formation and loss of electronic conductivity within the composite electrode. In LiBOB-based electrolytes the electrode kinetics increase in the order: carbon black << fine particulate graphite ~ metal powder, due to decreased film formation of the conductive additive. The influence of various solvents, surfactant additives, and potential impurities was also studied.     

Novel SEI formation of maleimide-based additives and its improvement of capability and cyclicability in lithium ion batteries

This investigation elucidates three maleimide (MI)-based aromatic molecules as additives in electrolyte that is used in lithium ion batteries. The 1.1 M LiPF₆ in ethylene carbonate (EC):propylene carbonate (PC):diethylene carbonate (DEC) (3:2:5 in volume) containing MI-based additives can prompt the formation of a solid electrolyte interface (SEI); and inhibit the entering into the irreversible state during lithium intercalation and co-intercalation. The reduction potential is 0.71-0.98 V versus Li/Li⁺ as determined by cyclic voltammetry (CV). The morphology and element analysis of the positive and negative electrode after the 100th charge-discharge cycle are examined by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS). Moreover, the MI was used in lithium ion batteries and provided 4.9% capacity increase and 16.7% capacity retention increase when cycled at 1C/1C. The MI-based additive also ensures respectable cycle-ability of lithium ion batteries. MI is decomposed electrochemically to form a long winding narrow SEI strip on the graphite surface. This novel SEI strip not only prevents exfoliation on the graphite electrode but also stabilizes the electrolyte. The MI-based additive also ensures respectable cycle-ability of lithium ion batteries.     

Electrochemical impedance characterization of FeSn2 electrodes for Li-ion batteries

This work reports the electrochemical characterization of a micro-scale FeSn₂ electrode in a lithium battery. The electrode is proposed as anode material for advanced lithium ion batteries due to its characteristics of high capacity (500 mAh g⁻¹) and low working voltage (0.6 V vs. Li). The electrochemical alloying process is studied by cyclic voltammetry and galvanostatic cycling while the interfacial properties are investigated by electrochemical impedance spectroscopy. The impedance measurements in combination with the galvanostatic cycling tests reveal relatively low overall impedance values and good electrochemical performance for the electrode, both in terms of delivered capacity and cycling stability, even at the higher C-rate regimes.     

含LiDFOB的FEC/PC/DMC基电解液的高电压电化学性能

利用氟代碳酸乙烯酯(FEC)和二氟草酸硼酸锂(LiDFOB)优良的成膜性、稳定性和耐高压性,研究了在1 mol/L LiPF6 FEC/碳酸丙烯酯(PC)/碳酸二甲酯(DMC)中加入LiDFOB和三(三甲基硅烷)硼酸酯(TMSB)对高电压材料LiNi0.5Mn1.5O4电化学性能的影响,利用循环伏安法和扫描电镜分析了两种电解液中电化学性能的差异. 结果表明,在FEC基电解液中加入LiDFOB和添加剂TMSB使电解液的分解电位提高至5.5 V(vs. Li/Li+)以上,对铝箔有良好的钝化作用. Li/LiNi0.5Mn1.5O4半电池在含LiDFOB和TMSB的电解液中的初始放电比容量达126.8 mA?h/g,库伦效率为99%,充放电200次后比容量仍为108.2 mA?h/g,容量保持率为85.3%. 而在不含LiDFOB和TMSB的电解液中,电池容量迅速衰减,85次充放电循环后容量保持率仅为60.7%.     

High voltage stability of LiCoO2 particles with a nano-scale Lipon coating

For high-voltage cycling of rechargeable Li batteries, a nano-scale amorphous Li-ion conductor, lithium phosphorus oxynitride (Lipon), has been coated on surfaces of LiCoO₂ particles by combining a RF-magnetron sputtering technique and mechanical agitation of LiCoO₂ powders. LiCoO₂ particles coated with 0.36 wt% (∼1 nm thick) of the amorphous Lipon, retain 90% of their original capacity compared to non-coated cathode materials that retain only 65% of their original capacity after more than 40 cycles in the 3.0–4.4 V range with a standard carbonate electrolyte. The reason for the better high-voltage cycling behavior is attributed to reduction in the side reactions that cause increase of the cell resistance during cycling. Further, Lipon coated particles are not damaged, whereas uncoated particles are badly cracked after cycling. Extending the charge of Lipon-coated LiCoO₂ to higher voltage enhances the specific capacity, but more importantly the Lipon-coated material is also more stable and tolerant of high voltage excursions. A drawback of Lipon coating, particularly as thicker films are applied to cathode powders, is the increased electronic resistance that reduces the power performance.     

High flash point electrolyte for use in lithium-ion batteries

The high flash point solvent adiponitrile (ADN) was investigated as co-solvent with ethylene carbonate (EC) for use as lithium-ion battery electrolyte. The flash point of this solvent mixture was more than 110 °C higher than that of conventional electrolyte solutions involving volatile linear carbonate components, such as diethyl carbonate (DEC) or dimethyl carbonate (DMC). The electrolyte based on EC:ADN (1:1 wt) with lithium tetrafluoroborate (LiBF₄) displayed a conductivity of 2.6 mS cm⁻¹ and no aluminum corrosion. In addition, it showed higher anodic stability on a Pt electrode than the standard electrolyte 1 M lithium hexafluorophosphate (LiPF₆) in EC:DEC (3:7 wt). Graphite/Li half cells using this electrolyte showed excellent rate capability up to 5C and good cycling stability (more than 98% capacity retention after 50 cycles at 1C). Additionally, the electrolyte was investigated in NCM/Li half cells. The cells were able to reach a capacity of 104 mAh g⁻¹ at 5C and capacity retention of more than 97% after 50 cycles. These results show that an electrolyte with a considerably increased flash point with respect to common electrolyte systems comprising linear carbonates, could be realized without any negative effects on the electrochemical performance in Li-half cells.