液态金属电极的电化学储能应用

液态金属电极电导率高,电极界面容易构建,在充放电过程中可有效避免电极结构形变、枝晶生长等问题,在储能电池领域具有重要应用价值. 本文主要讨论了液态金属电极在液态金属电池、钠硫电池和ZEBRA电池中的应用进展,重点介绍了液态金属电池关键材料体系、充放电机制及电池构型等,评述了液态金属电极储能应用中涉及的熔盐电解质、固态陶瓷隔膜、多场影响因素等方面的重要研究进展,分析了高温密封、腐蚀防护等关键问题,明确了液态金属电极在储能电池应用中的发展方向.     

Nano lithium aluminate filler incorporating gel lithium triflate polymer composite: Preparation,characterization and application as an electrolyte in lithium ion batteries

Gel polymer composites electrolytes containing nano LiAlO₂ as filler were prepared using a solution cast technique and characterized using different techniques such as X-ray diffraction (XRD), thermal analysis (TG, DSC), Fourier transform infra – red spectroscopy (FT-IR) and scanning electron microscope (SEM). X-ray diffraction analysis showed the effect of lithium tri fluoro methane sulphonate (LiCF₃SO₃), poly vinyl acetate (PVAc) and nano lithium aluminate (LiAlO₂) on the crystalline structure of the poly vinylidene fluoride –co– hexa fluoro propylene (PVDF-co-HFP) matrix containing ethylene carbonate (EC) and diethyl carbonate (DEC) as plasticizers. FT-IR analysis confirmed both the good dissolution of the LiCF₃SO₃ salt and the good interaction of the nano LiAlO₂ filler with the polymer matrix. TG analysis showed the good thermal stability of the LiAlO₂ samples compared to the free one. Also, addition of nano LiAlO₂ filler enhanced the conductivity value of the polymer composites electrolytes. The sample containing 2 wt% of LiAlO₂ showed the highest conductivity value, 4.98 × 10⁻³ Ω ⁻¹ cm⁻¹ at room temperature, with good thermal stability behavior (T_d = 362 °C). This good conductive and thermally stable polymer nano composite electrolyte was evaluated as a promising membrane for lithium ion batteries application.     

微孔型聚丙烯腈固体电解质的结构与导电性能研究

用蒸汽相沉析法和液相沉析法分别制备了两类高孔隙率的聚丙烯腈 (PAN)微孔膜 .用扫描电子显微镜对微孔膜的形态进行了观察 ,发现前者为均匀的蜂窝状结构 ,而后者则具有不对称的三层次结构 .又用这两类微孔膜分别制备了两个系列的微孔型PAN电解质 .电性能测试表明前者的室温电导率较高 ,可以达到 4×10 - 3 S cm ,后者的电导率则相对较低 .微孔膜本身诸因素对微孔型PAN电解质电导率的影响顺序为微孔膜结构—孔隙率—微孔孔径     

锂离子二次电池用PVDF-HFP/PAMA共混物基聚合物电解质膜的研制

以丙烯腈(AN)、甲基丙烯酸甲酯(MMA)、丙烯醛(A)为单体,采用乳液聚合法制成一种共聚物———聚(丙烯腈 甲基丙烯酸甲酯 丙烯醛) (PAMA) .将PAMA作为第二共聚物与聚(偏氟乙烯 六氟丙烯) (PVDF -HFP)共混,并向反应体系中添加纳米级SiO2 ,充分混合后利用二次相转移法制得薄膜,并对所得薄膜的断面形貌、吸附性能、热性能、导电性能等进行了测试.研究发现,SiO2 的加入增大了膜中微孔体积,改善了微孔分布,且增大了电解液的吸附量;共聚物PAMA的组成影响薄膜的吸附性能,其中极性较大的丙烯醛单元和丙烯腈单元起着决定性作用;PAMA含量的增加使得共混膜吸附电解液量增加.制得共混膜的离子电导率达2 . 30×10 - 3S cm .     

新型球状磷酸铁锂的合成及电化学性能

在水热条件下,制备了水合碱式磷酸铁微球,500 oC焙烧后生成直径为5μm的碱式磷酸铁,接着与碳酸锂一起焙烧后生成了球形磷酸铁锂．我们的方法可以有效地控制所获得产物的尺寸和形貌,同时在产物表面形成均匀碳包覆,改善了磷酸铁锂的电化学性能．     

锂离子电池用聚合物固体电解质的新进展

综述了锂离子电池用聚合物固体电解质方面的进展。     

新型锂电池用复合隔膜的制备及其电化学性能表征

利用浸渍法在聚丙烯微孔膜(Celgard2400)表面涂覆掺有纳米二氧化硅的聚氧乙烯(PEO),制备了新型锂电池用复合隔膜.采用交流阻抗法、扣式电池充放电等实验技术测试了复合隔膜的电化学性能.     

Lithium–Sulfur Batteries: Electrochemistry,Materials, and Prospects

With the increasing demand for efficient and economic energy storage, Li‐S batteries have become attractive candidates for the next‐generation high‐energy rechargeable Li batteries because of their high theoretical energy density and cost effectiveness. Starting from a brief history of Li‐S batteries, this Review introduces the electrochemistry of Li‐S batteries, and discusses issues resulting from the electrochemistry, such as the electroactivity and the polysulfide dissolution. To address these critical issues, recent advances in Li‐S batteries are summarized, including the S cathode, Li anode, electrolyte, and new designs of Li‐S batteries with a metallic Li‐free anode. Constructing S molecules confined in the conductive microporous carbon materials to improve the cyclability of Li‐S batteries serves as a prospective strategy for the industry in the future.     

Sulfone-based high-voltage electrolytes for high energy density rechargeable lithium batteries:Progress and perspective

Further enhancement in the energy density of rechargeable lithium batteries calls for high-voltage cathode materials and stable anodes,as well as matched high-voltage electrolytes without compromising the overall property of batteries.Sulfone-based electrolytes have aroused great interest in recent years owing to their wide electrochemical window and high safety.However,significant challenges such as the complexity of synthesis,high melting point(typically above room temperature),high viscosity,and their poor compatibility with graphite-based anodes have drastically impeded their practical applications.In this review,recent progress of sulfone solvents in high energy density rechargeable lithium batteries is summarized theoretically and experimentally.More importantly,general improvement methods of sulfone-based electrolytes,such as adding additives and cosolvents,structural modifications of sulfo ne,superconcentrated salt strategy are briefly discussed.We expect that this review provides inspiration for the future developments of sulfone-based high-voltage electrolytes(SHVEs) and their widespread applications in high specific energy lithium batteries.     

New fluorine-containing plasticized low lattice energy lithium salt for plastic batteries

The synthesis of a new plasticized low lattice energy lithium salt (PLI), structurally related to lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), is described. Incorporation of the plasticizing moiety in a single salt molecule greatly simplifies the solid polymer electrolyte (SPE) processing formulation without compromising performance. Thermally and electrochemically stable polymer electrolyte films of PLI exhibit good ionic conductivity, though somewhat lower than that for LiTFSI. The pentafluorophenyl analog of LiTFSI, prepared by two approaches, exhibits behavior similar to that of LiTFSI.     

Magnesocene‐Based Electrolytes: A New Class of Electrolytes for Magnesium Batteries

Unlike ferrocene, bis(η⁵‐cyclopentadienyl)magnesium (magnesocene, MgCp₂) is slightly dissociated in solvents, such as ethers, resulting in electrolyte solutions with low conductivity. MgCp₂/tetrahydrofuran solutions make possible reversible magnesium plating and stripping with low over‐potentials for many cycles. The Mg deposits appear with a cauliflower‐like morphology. IR and NMR spectroscopy confirm that the electrolyte is stable and not decomposed during prolonged cycling. The anodic stability limit is in the range of 1.5 V (at platinum) and 1.8 V versus Mg/Mg²⁺ (at stainless steel), which may be sufficient for low‐voltage cathode materials. MgCp₂ is a first example of a completely new class of halide‐free electrolytes, which may open up a new research direction for future magnesium metal and magnesium‐ion batteries.     

Li[B(OCH2CF3)4]: Synthesis,Characterization and Electrochemical Application as a Conducting Salt for LiSB Batteries

A new Li salt with views to success in electrolytes is synthesized in excellent yields from lithium borohydride with excess 2,2,2‐trifluorethanol (HOTfe) in toluene and at least two equivalents of 1,2‐dimethoxyethane (DME). The salt Li[B(OTfe)₄] is obtained in multigram scale without impurities, as long as DME is present during the reaction. It is characterized by heteronuclear magnetic resonance and vibrational spectroscopy (IR and Raman), has high thermal stability (T_{decomposition}>271 °C, DSC) and shows long‐term stability in water. The concentration‐dependent electrical conductivity of Li[B(OTfe)₄] is measured in water, acetone, EC/DMC, EC/DMC/DME, ethyl acetate and THF at RT In DME (0.8 mol L ^?1) it is 3.9 mS cm^?1, which is satisfactory for the use in lithium‐sulfur batteries (LiSB). Cyclic voltammetry confirms the electrochemical stability of Li[B(OTfe)₄] in a potential range of 0 to 4.8 V vs. Li/Li⁺. The performance of Li[B(OTfe)₄] as conducting salt in a 0.2 mol L ^?1 solution in 1:1 wt % DME/DOL is investigated in LiSB test cells. After the 40th cycle, 86 % of the capacity remains, with a coulombic efficiency of around 97 % for each cycle. This indicates a considerable performance improvement for LiSB, if compared to the standard Li[NTf₂]/DOL/DME electrolyte system.     

低聚离子液体的体相与界面及其电化学储能应用

近年来,随着单阳离子液体的发展,新型低聚物离子液体被合成并应用。这类离子液体可看作是由几个重复的单阳离子组合而成,可以通过改变阳离子带电基团、间隔连接的长度或种类、末端链的长度以及阴离子种类来获得更多不同的结构。因此,低聚离子液体有更复杂的微观结构和内部相互作用,决定了其多特征的物化性质和电化学特性,有望满足更多对溶剂性能有特定要求的应用。例如,与单阳离子液体相比,低聚离子液体具有更大的可调节性、更宽的液态温度范围、更高的热稳定性等优点,使其在电化学储能设备中得到越来越多的应用,如用作超级电容器和锂离子电池的电解液。在本综述中,我们系统地总结并详细解释了低聚离子液体的性质和结构（包括单个离子的结构和本体液内部的纳米组织）之间的关联,主要是双阳离子液体和三阳离子液体;概括了低聚离子液体作为超级电容器和锂离子电池的电解液的相关研究,重点阐述了由低聚离子液体和不同类型电极组成的双电层的结构和性能,以及与相应单阳离子液体电解液的比较结果;提供了降低低聚离子液体粘度和加速离子扩散的优化措施,提出了低聚离子液体电解液未来可能面临的主要问题和发展前景。     

Electrochemical properties of mesoporous iron phosphate in lithium batteries

Mesoporous iron phosphate containing CTAB as templating agent was synthesized and characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy and TGA techniques. The mesoporous material shows a highly ordered structure, that collapses when submitted to extraction with acetate ions. The treatment of the exchanged samples at 573 K under nitrogen atmosphere leads to amorphous phases with an electrochemical behaviour typical of carbon-coated iron phosphate electrodes. The existence of this coating, proceeding from incomplete pyrolysis of the organic exchange agent, enhances the electronic properties of the system, as evidenced by galvanostatic experiments and impedance spectroscopy measurements.     

Electrochemical lithium insertion in β-MoO<Subscript>3</Subscript>: novel Li<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>MoO<Subscript>3</Subscript> bronzes

New lithium molybdenum bronzes have been synthesized by electrochemical lithium insertion. Through electrochemical spectroscopy techniques we have detected that lithium insertion proceeds at least in a two-step reduction process. The maximum amount of lithium inserted in β-MoO₃ leads to a high specific capacity of the cell of 370 Ah kg^–1. However, this capacity was lost after the first charge-discharge cycle, resulting in a total loss of 25%, due to structural transformations. The structural study of the insertion process showed that each step of the process can be associated with the formation of different single phases of variable composition, Li _x MoO₃. Electronic Publication     

Electrochemical noise of a lithium electrode in organic electrolytes: A study by a correlation function method

Fluctuations of the potential of a lithium electrode in conditions of galvanostatic polarization in aprotic organic electrolytes are studied by a method of correlation functions. Computer-aided removal of heavy interference in the form of slow variation of the electrode potential proved to be possible to perform with use made of fifth-power polynomials. The time coordinate of the first zero in the correlation function weakly depends on the electrolyte type and lies within the limits 1.5–3 s. At the same time, the electrolyte type affects the dispersion of the electrode potential fluctuations in a substantial manner. In so doing, lithium systems that feature a high cycling efficiency possess a lower level of noise.     

羰基化合物在新型绿色能源有机钠离子电池中的应用

有机钠离子电池是一种以有机物作为电极材料的新型二次电池。但有机物作为钠离子电池电极材料仍存在较低的氧化还原电位、高的溶解性和低的导电性等问题。解决这些问题通常采用引入吸电子基团来提高氧化还原电位,形成聚合物来降低溶解性和引入导电基底增加导电性等方法。着重关注羰基化合物作为钠离子电池电极材料,分别介绍羰基化合物/聚合物及其与导电基底形成的复合物和柔性电极在钠离子电池中的应用。     

Hydrothermal Synthesis of Na0.28V2O5 Nanobelts and their Electrochemical Behavior in Lithium Batteries

A simple low temperature hydrothermal method was found to yield Na_0.28V₂O₅ nanobelts after two days at 130 °C in acidic medium (H₂SO₄) without using any surfactant. The obtained products were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), and Raman spectroscopy. Their morphology was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Additionally, their electrochemical behavior in a lithium battery was investigated. The XRD pattern shows that the product is composed of monoclinic Na_0.28V₂O₅ nanobelts. From the FTIR spectrum, the band centered at 961 cm^–1 is assigned to V=O stretching vibration, which is sensitive to intercalation and suggests that Na⁺ ions are inserted between the vanadium oxide layers. SEM/TEM analyses reveal that the products consist of a large quantity of nanobelts which have a thickness of 60–150 nm and a length of several tens of micrometers. The electrochemical results show that the nanobelts exhibit an initial discharge specific capacity of 390 mAh · g^–1, and its stabilized capacity still remained around 200 mAh · g^–1 after the 18th cycle.     

Electrochemical Behavior of Polypyrrole‐modified SnS2 for Use as Anode Material in Lithium‐Ion Batteries

SnS₂/polypyrrole (PPy) composites were successfully synthesized by PPy modification of SnS₂ via a simple and effective solvothermal and chemical method. The microstructure, morphology, electrical conductivity, PPy content, and electrochemical properties of these materials were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), four‐point probe technique, thermogavimetry (TG), and constant‐current charge/discharge tests, respectively. The results demonstrate that PPy is tightly coated on the 3D flower‐like SnS₂ and that the conductivity of SnS₂ /PPy composites can be greatly improved by the PPy modification. The electrochemical results indicate that PPy is not involved in the electrode reaction, but it can dramatically improve the reversible capacity and cyclic performance. The recharge capacity retention after 30 cycles remained at 523 mAh/g, which is significantly higher than that of SnS₂ without modification by PPy. The better cycling performance compared to SnS₂ nanoparticles should be due to the 3D nano‐flower‐like SnS₂ particles and the modification of SnS₂ by PPy.