聚合物固态电解质设计策略

电解质作为锂离子电池中最为关键的部分之一,决定了锂离子电池的性能。固态电解质相比传统的电解液具有良好的机械强度、优越的安全性等,其中聚合物固态电解质不仅极大降低了锂离子电池的安全隐患,同时表现出优异的机械加工性能,具有良好的弹性和柔韧性,易制备加工成不同的形状。相较于氧化物固态电解质,聚合物固态电解质的柔性使其能很好地贴合电极,阻抗低,合成条件较为简易,对温度、压力等环境要求不苛刻,适宜规模化生产。但聚合物固态电解质的发展应用仍然存在诸多阻碍,在室温下,其离子电导率远远达不到目前对于锂离子电池能量密度的理想需求。既要兼顾聚合物的离子电导率,又要尽可能保留机械强度,是目前需要解决的首要问题。需要搞清楚在分子层面影响聚合物固态电解质离子电导率和高压稳定性的因素,同时探索新型聚合物、共聚物、复合型材料用于其制备中。调节分子间相互作用是一种有前途的提高离子电导率的解决方案。目前相关研究主要集中在开发新型聚合物、开发有效添加剂、针对不同电池系统优化聚合物固态电解质的微观结构三个方面。     

PVDF-HFP基凝胶固态聚合物电解质的合成与锂离子电池性能

聚偏氟乙烯-六氟丙烯(PVDF-HFP)基凝胶聚合物电解质被认为是解决锂电安全性问题的一种有前途的固态电解质.然而,目前报道的是凝胶固态聚合物电解质由于含有大量易燃物质,安全性仍然无法保证.因此,本文合成制备基于PVDF-HFP的新型凝胶聚合物电解质,使用丁二腈(SN)作为塑化剂,双三氟甲基磺酰胺亚锂(LiTFSI)作为锂盐,利用热交联法原位制备了高热稳定性的新型凝胶固态聚合物电解质(GSPE).优化后的凝胶聚合物电解质离子电导率在25℃时可高达3.7×10?3 S/cm,电化学窗口室温下可达4.5 V.此外,凝胶聚合物电解质与电极具有良好的界面相容性;组装的磷酸铁锂电池在1 C下循环80次,容量保持率为89％.本项研究工作展示了高性能凝胶聚合物电解质对提升锂离子电池的循环稳定性与安全性具有较大潜在的应用价值.     

新型固态聚合物电解质在锂硫电池中的性能研究

本工作采用（氟磺酰）（三氟甲基磺酰）亚胺锂{Li[(FSO2)(CF3SO2)N],LiFTFSI}和聚氧乙烯（PEO）分别作为导电锂盐和聚合物主链,通过简单的溶液浇铸法制备了新型固态聚合物电解质（SPEs）,并采取示差扫描量热（DSC）、热重（TGA）、线性扫描伏安（LSV）、交流阻抗（EIS）和恒电位直流（DC）极化等方法研究了LiFTFSI/PEO （EO/Li+摩尔比为16）电解质的理化性质和电化学性质。结果表明,LiFTFSI/PEO电解质具有较高的室温离子电导率（σ ≈10−5 S/cm）,较高的氧化电位（4.63 V vs. Li/Li+）,并且耐热温度高达256 ℃。锂硫电池测试结果表明,该类SPEs展现出相对高的首周放电比容量（881 mA•h/g）,有效地抑制了多硫离子的“穿梭效应”,表现出良好的电池循环性能。     

石榴石型Li7La3Zr2O12固态锂金属电池的界面问题研究进展

固态锂金属电池具有高能量密度、高安全性、宽工作温度范围、长服役寿命等优势,是下一代锂电池体系的重要发展方向之一.作为典型的氧化物固态电解质,Li7La3Zr2O12(LLZO)具有锂离子电导率高、电化学窗口较宽、机械强度高和热稳定性好等优点,因此LLZO固态锂金属电池受到业界的广泛关注.但是,LLZO固态锂金属电池还存...     

原位表征技术在固态电池界面研究中的应用

原位表征技术已被广泛应用在固态电池（SSB）的界面研究中,为揭示SSB充放电过程中界面结构演化以及工作机制提供了重要依据。与非原位表征技术相比,原位表征技术不需要对SSB进行拆卸,避免了外界环境对固态电解质（SE）和电极材料造成污染,提高测试的准确性。总结了电极/SE界面研究中经常使用的原位表征技术,包括原位X射线衍射（XRD）、原位拉曼光谱（RS）、原位扫描电镜（SEM）、原位透射电镜（TEM）以及原位X射线光电子能谱（XPS）,并结合相关应用案例进行分析。     

PEO基Li^(+)-g-C_(3)N_(4)复合固态电解质的制备及其电化学性能北大核心CSCD

利用g-C_(3)N_(4)表面丰富的官能团进行锂化,得到锂化氮化碳(L-g-C_(3)N_(4))材料,并以双三氟甲基磺酰亚胺锂(LiTFSI)为锂盐,聚环氧乙烯(PEO)为聚合物基体,采用流延-热压法制备Li^(+)-g-C_(3)N_(4)复合固态电解质。借助透射电子显微镜(TEM)、X射线衍射仪(XRD)、红外光谱仪(FT-IR)、差示扫描量热法(DSC)、线性循环伏安(LSV)、直流极化曲线、交流阻抗谱以及充放电测试等手段对复合固态电解质进行表征和测试。对比分析相同质量分数g-C_(3)N_(4)复合固态电解质与L-g-C_(3)N_(4)复合固态电解质的电化学性能,同时对不同L-g-C_(3)N_(4)含量的复合固态电解质的电化学性能进行研究。结果表明,添加质量分数为10%L-g-C_(3)N_(4)的复合固态电解质在60℃时的离子电导率为3.95×10^(-4) S/cm,锂离子迁移数为0.639,电化学窗口为4.5 V以上。以复合固态电解质组装Li/LiFePO_(4)全固态电池,在60℃以0.5 C充放电,电池的首次放电比容量为163.76 mAh/g,循环80次后容量仍有160.10 mAh/g,容量保持率为97.8%。     

甲氧基聚乙二醇丙烯酸酯在全固态电池中的应用北大核心CSCD

固态聚合物电解质作为全固态聚合物锂离子电池的核心材料,目前面临的主要难点是电导率低、电化学稳定性差等题。基于聚合物电解质的锂离子传输机理,采用甲氧基聚乙二醇丙烯酸酯和聚氧化乙烯制备出多支链固态聚合物电解质(PMEA@SSE),并以聚氧化乙烯固态电解质(PEO@SSE)作为对比样,对PMEA@SSE进行了傅里叶变换红外光谱仪(FT-IR)、电化学阻抗谱(EIS)、线性扫描伏安法(LSV)、扫描电子显微镜(SEM)、X射线能谱(EDS)、X射线衍射(XRD)以及全固态电池循环等测试和分析。结果表明,与PEO@SSE相比,PMEA@SSE具有更高的离子电导率(0.13 mS/cm vs.0.018 mS/cm,测试温度30℃),更宽的电化学窗口(4.2 V vs.3.8 V),以及更好的全固态电池循环稳定性(77次vs.31次循环,80%容量保持率,60℃下测试,0.1 C倍率,3.0~4.2 V电压范围)。本工作表明,甲氧基聚乙二醇丙烯酸酯部分替代聚氧化乙烯是一种改进聚氧化乙烯这一经典固态聚合物电解质材料的可行策略,将为后续固态聚合物电解质新材料的开发提供有益参考。     

钴掺杂二氧化铈基层状复合固态电解质的制备及其性能北大核心CSCD

开发具有高离子传导率和高力学性能的薄型固态电解质对于制备高性能全固态锂金属电池非常重要。本工作首先制备了钴掺杂的二氧化铈(Co^(2+)@CeO_(2))纳米片,后将其与聚氧化乙烯(PEO)混合通过真空抽滤制得厚度仅为32μm的Co^(2+)@CeO_(2)层状复合固态电解质(L-CSE)。富含氧空位的Co^(2+)@CeO_(2)纳米片在提高离子电导率和力学性能方面发挥了重要作用,同时PEO作为黏结剂确保了电解质与电极之间的紧密接触并且增强了其柔韧性。通过改变Co的掺杂量调控纳米片上氧空位含量,重点探究了氧空位含量对Li^(+)传递特性的影响,并对L-CSE的结构组成、力学性能和电化学性能进行了系统研究。结果表明:通过调控Co的掺杂量能够准确控制纳米片上氧空位的含量,且0.33Co^(2+)@CeO_(2)纳米片表面的氧空位含量最多。所制备的L-CSE具有良好的力学性能(弹性模量达到1.147 GPa);30℃下,L-CSE的离子传导率达到5.81×10^(-5) S/cm;60℃下Li^(+)迁移数达到0.59。同时由于电解质与锂负极间具有较好的界面稳定性,在0.7 mA/cm^(2)的高电流密度下,组装的锂对称电池能稳定运行40 h。此外,所组装的磷酸铁锂(LFP)/L-CSE/Li固态电池也表现出良好的循环稳定性和倍率性能,在60℃、0.5 C下,能够稳定循环200次,容量保持率为83.6%;在2 C放电倍率下,放电比容量能达到120.7 mAh/g。     

准固态电解质在染料敏化太阳电池中的应用和发展

染料敏化太阳电池（DSCs,dye-sensitized solar cells）近年已经成为一个研究热点。而电解质对电池的效率和稳定性起着重要的作用。目前常用的乙腈基液态电解质存在封装和泄漏的问题,尤其是在高温下。将准固态聚合物电解质应用到 DSCs 中可以有效解决应用液态电解质遇到的封装难稳定性差等问题,因而近年来,对准固态电解质的研究引起了广泛关注。本文综述了准固态电解质的研究进展,根据固化方式的不同将准固态电解质分为：有机小分子凝胶电解质、聚合物凝胶电解质和添加纳米粒子的凝胶电解质;讨论了每种准固态电解质的特点及存在的问题;最后对准固态电解质的发展进行展望。     

磺酸型聚乙烯亚胺单离子导体聚合物电解质的制备及其电化学性能研究

通过胺基与双键官能团的迈克尔加成反应将2-丙烯酰胺基-2-甲基丙磺酸锂(AMPSLi)接枝到聚乙烯亚胺(PEI)链上,对PEI进行功能化改性制备磺酸型单离子导体PEI-AMPSLi,再与聚丙烯腈(PAN)通过静电纺丝制备纳米纤维膜.纳米纤维膜吸收电解液后得到单离子导体聚合物电解质,经热交联处理的聚合物电解质具有10.6...     

The potential of polyurethane bio-based solid polymer electrolyte for photoelectrochemical cell application

A photoelectrochemical cell was developed from bio-based polyurethane (PU), solid polymer electrolyte with lithium iodide as conducting material. At the initial stage, PU prepolymer was prepared via prepolymerization technique by reacting palm kernel oil-based monoester-OH (PKO-p) and 2,4′-methylene diphenyl diisocyanate (2,4′-MDI). The polyurethane electrolyte film was then prepared by inclusion of varying amount of lithium iodide (LiI) via solution casting technique. The formation of urethane linkages (NHCO backbone) and the chemical interaction between segmented polyurethane and lithium ion from LiI salts were confirmed by ATR-FTIR technique. Thermal studies carried out by TGA have proven the occurrence of polymer-salt complexation. Structural analysis by XRD has revealed that polyurethane electrolytes with 25 wt.% LiI reduced the semi-crystalline characteristics of plasticized polyurethane. The SEM morphological observation on the fractured film indicated the absence of phase separation. The ionic conductivity increased with the addition of 25 wt.% LiI resulted in the highest conductivity of 7.6 × 10⁻⁴ S cm⁻¹. The temperature dependence conductivity of the electrolytes obeyed the Arrhenius law with the pre-exponential factor, σ_o of 2.4 × 10⁻³ S cm⁻¹ and activation energy, E_a of 0.11 eV. A dye-sensitized solar cell of FTO/TiO₂-dye/PU-LiI-I₂/Pt give a response under light intensity of 100 mW cm⁻² indicated the photovoltaic effect with the J_sc of 0.06 mA cm⁻² and V_oc of 0.14 V respectively. These properties exhibited promising potentials for photoelectrochemical cell giving the focus on bio-based polymer electrolyte.     

Ion pair formation and its effect in PEO:Mg solid polymer electrolyte system

In poly(ethylene oxide) (PEO) based solid polymer electrolytes, the interaction between cations and the ether oxygen plays a major role in ion conductivity. Measurements with differential scanning calorimetry (DSC) illustrated clearly the modification of the PEO crystalline structure with increasing content of magnesium salt. FTIR spectral studies suggest interaction of Mg²⁺ cations with the ether oxygen of PEO, where a 1100 cm⁻¹ broad band corresponds to COC stretching and severe deformation occurs. A spectral band at ∼623 cm⁻¹ corresponds to the ClO₄⁻ anion and shows the growth of a shoulder at a higher wave number with increasing salt content. The apparent new envelope at ∼634.5 cm⁻¹ clearly indicates ClO₄⁻–Mg²⁺ ion pairing. Ionic conductivity increases with salt content, and is optimized at 15 wt.% Mg salt (O:Mg ratio 28:1). The decrease in ion conductivity at higher salt contents is due to ion–ion association, which leads to ion pair formation (i.e. aggregation of ionic salt) and retards the motion of ions.     

Halogen acid electrolysis in solid polymer electrolyte cells

The use of solid polymer electrolyte systems has been extended to the electrolysis of aqueous HCl and HBr. The reduced internal losses in these cells permits the production of hydrogen and the halogen at an energy consumption considerably less than that reported previously. Data are presented for the operational characteristics of the solid polymer electrolyte acid electrolysers operating over a range of current densities, pressures, feedstock compositions, and temperatures.     

固态聚合物电解质导电锂盐的研究进展

固态聚合物电解质(solid polymerelectrolytes,SPEs)具有不易泄漏、易加工、抑制锂枝晶生长等优点,能提高固态金属锂电池(solid-state lithiummetalbatteries,SSLMBs)的循环寿命和安全性。导电锂盐作为SPEs的必要组分之一,不仅能够为其离子输运提供锂离子源,而且能够在电极表面发生化学或电化学反应,参与电极/SPE界面膜的构建。因此,导电锂盐的分子结构对于调控SPEs的基础物理和电化学性质及其与电极材料的界面性能有着重要的影响。结合本团队在SPEs导电锂盐领域的相关研究工作,本文主要介绍全氟代和部分氟代磺酰亚胺锂盐作为SPEs导电盐的研究进展,并探讨了SPEs导电锂盐的未来发展方向。     

Thermal and electrochemical stability of cathode materials in solid polymer electrolyte

Thermal stability of cathode materials, including LiCoO₂, LiNiO₂, LiMn₂O₄, V₂O₅, V₆O₁₃, and Li_xMnO₂ in contact with poly(ethylene oxide) (PEO) based solid polymer electrolyte was systemically investigated by means of thermal analysis in combination with X-ray diffraction technique (XRD). The differential scanning calorimetry (DSC) analysis showed significant exothermic reaction of both LiNiO₂ and LiCoO₂ in contact with the polymer electrolyte. LiMn₂O₄ was less reactive compared with LiNiO₂ and LiCoO₂. V₂O₅, V₆O₁₃, and Li_xMnO₂ were also found less reactive, especially in their discharge states. The XRD results indicated that the thermal decomposition products of the cathode material were the low valance metal oxides, suggesting the exothermic reaction was an oxidation reaction of the polymer electrolyte with active material. The decomposition temperature is somehow dependent on the potential of the cathode active materials. Cyclic voltammetry reveals that PEO based solid polymer electrolyte is stable up to 5.0 V versus Li/Li⁺ at a blocking electrode, whereas it decomposes at ca 3.8 V when contacted with a carbon composite electrode.     

Improved performance of Li hybrid solid polymer electrolyte cells

The seminal research by Wright et al. on polyethylene oxide (PEO) solid polymer electrolyte (SPE) generated intense interest in all solid-state rechargeable lithium batteries. Following this a number of researchers have studied the physical, electrical and transport properties of thin film PEO electrolyte containing Li salt. These studies have clearly identified the limitations of the PEO electrolyte. Chief among the limitations are a low cation transport number (t₊), high crystallinity and segmental motion of the polymer chain, which carries the cation through the bulk electrolyte. While low t₊ leads to cell polarization and increase in cell resistance high T_g reduces conductivity at and around room temperatures. For example, the conductivity of PEO electrolyte containing lithium salt is <10⁻⁷ S cm⁻¹ at room temperature. Although modified PEO electrolytes with lower T_g exhibited higher conductivity (∼10⁻⁵ S cm⁻¹ at RT) the t₊ is still very low ∼0.25 for lithium ion. Numerous other attempts to improving t₊ have met with limited success. The latest approach involves integrating nano domains of inorganic moieties, such as silcate, alumosilicate, etc. within the polymer component. This approach yields an inorganic–organic component (OIC) based polymer electrolyte with higher conductivity and t₊ for Li⁺_. This paper describes the improved electrical and electrochemical properties of OIC-based polymer electrolyte and cells containing Li anode with either a TiS₂ cathode or Mag-10 carbon electrode. Several solid polymer electrolytes derived from silicate OIC and salt-in-polymer constituent based on Li triflate (LiTf) and PEO are studied. A typical composition of the SPE investigated in this work consists of 600 kDa PEO, lithium triflate (LiTf, LiSO₃CF₃) and 55% of silicate based on (3-glycidoxypropyl)trimethoxysilane and tetramethoxysilane at molar ratio 4:1 and 0.65 mol% of aluminum(tri-sec-butoxide) (GTMOS-Al1-900k-55%). Several pouch cells consisting of Li/OIC-based–SPE/cathode containing OIC-based–SPE–LiTf binder were fabricated and tested, these cells are called modified cells. The charge/discharge and impedance characteristics of the new cells (also called modified cells) are compared with that of the pouch cells containing the conventional PEO–LiTf electrolyte as the cathode binder, these cells are called non-modified cells. The new cells can be charged and discharged at 70 °C at higher currents. However, the old cells can be charged and discharged only at 80 °C or above and at lower currents. The cell impedance for the new cells is much lower than that for the old cells.     

Effect of zwitterion on the lithium solid electrolyte interphase in ionic liquid electrolytes

An understanding of the solid electrolyte interphase (SEI) that forms on the lithium-metal surface is essential to the further development of rechargeable lithium-metal batteries. Currently, the formation of dendrites during cycling, which can lead to catastrophic failure of the cell, has mostly halted research on these power sources. The discovery of ionic liquids as electrolytes has rekindled the possibility of safe, rechargeable, lithium-metal batteries. The current limitation of ionic liquid electrolytes, however, is that when compared with conventional non-aqueous electrolytes the device rate capability is limited. Recently, we have shown that the addition of a zwitterion such as N-methyl-N-(butyl sulfonate) pyrrolidinium resulted in enhancement of the achievable current densities by 100%. It was also found that the resistance of the SEI layer in the presence of a zwitterion is 50% lower. In this study, a detailed chemical and electrochemical analysis of the SEI that forms in both the presence and absence of a zwitterion has been conducted. Clear differences in the chemical nature and also the thickness of the SEI are observed and these may account for the enhancement of operating current densities.     

Great reversible capacity of carbon lithium electrode in solid polymer electrolyte

The reversible storage capacity of lithium in a mesophase-derived semi-coke, heat-treated (HTT) below 700°C, was found by far exceeding the theoretical value corresponding to the LiC₆ composition. A capacity as high as 1660 mAh/g was obtained in the case of carbon, heat-treated at ∼ 450 °C, when poly(ethylene oxide)-based electrolyte is used in lithium cells operated at 100 °C. This great capacity is discussed on the basis of a model where lithium forms multilayers on the external basal surfaces of the nanometric size mesocarbon domains.     

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。     

Advances in oxygen evolution catalysis in solid polymer electrolyte water electrolysis

Continuous polarization of a stabilized RuO₂ oxygen anode in a solid polymer electrolyte water electrolysis cell at 1072 mA cm^?2 resulted in severe anode deterioration within 24–48 hr. In contrast, a new Ru-based mixed oxide catalyst, termed WE-3, exhibited stability in oxygen evolution over a 6700 hr period, with testing beyond that point still in progress. The activation energy for oxygen evolution on WE-3 is comparable to that observed on new RuO₂ anodes.