High reversible capacity carbon-lithium negative electrode in polymer electrolyte

Cabonaceous materials from different types are used in polymer electrolyte-based lithium cells in order to evaluate their electrochemical performance during lithium storage in the application as the negative electrode in lithium-ion-type batteries. The formation of a passivating film during the first cathodic polarization may account for the low faradaic yield of the first cycle. It also plays an important role in the stabilization of the carbon/polymer electrolyte interface. Non-graphitized mesocarbon micro beads lead to a higher reversible capacity of 410 mAh/g than the graphitized one. It is suggested that lithium could be reversibly stored as a multilayer ‘deposit’ at the carbon surface. A model of epitaxial lithium electroplating is presented.     

Lithium polymer batteries and proton exchange membrane fuel cells as energy sources in hydrogen electric vehicles

This paper deals with the application of lithium ion polymer batteries as electric energy storage systems for hydrogen fuel cell power trains. The experimental study was firstly effected in steady state conditions, to evidence the basic features of these systems in view of their application in the automotive field, in particular charge-discharge experiments were carried at different rates (varying the current between 8 and 100 A). A comparison with conventional lead acid batteries evidenced the superior features of lithium systems in terms of both higher discharge rate capability and minor resistance in charge mode. Dynamic experiments were carried out on the overall power train equipped with PEM fuel cell stack (2 kW) and lithium batteries (47.5 V, 40 Ah) on the European R47 driving cycle. The usage of lithium ion polymer batteries permitted to follow the high dynamic requirement of this cycle in hard hybrid configuration, with a hydrogen consumption reduction of about 6% with respect to the same power train equipped with lead acid batteries.     

Electrochemical behaviour of lead oxides in aprotic organic electrolyte solutions

Of the various lead oxides tested, red lead (Pb₃O₄) proved to be the most suitable for use as cathode material in lithium cells having a voltag     

The effect of lithium addition on aluminum-reinforced α-LiAlO2 matrices for molten carbonate fuel cells

The effect of lithium hydroxide (LiOH) addition as a lithium source is discussed as a way to prevent Li-ion shortages in aluminum-based α-LiAlO₂ matrices of molten carbonate fuel cells. Our results show that the use of LiOH as a lithium source to prevent a Li-ion shortage caused by a lithiated Al-reaction during the operation of the cell allows for more stable performance and greater durability than when lithium carbonate (Li₂CO₃) is used as the lithium source. The behavior of high-lithium content mixtures is attributed to the presence of reactive aluminum particles, which promote the formation of lithium aluminate (LiAlO₂) phases at 650 °C. The incorporation of low-melting-point lithium and an efficient pathway to the aluminum in a reinforced matrix has improved the in-situ mechanical strength via the lithiated Al-reaction, and they do not lead to any noticeable loss in cell performance, even after 4000 h of operation. From the post-test results, the cell with LiOH stored in the cathode channel shows effective formation of the stable crystalline phase of α-LiAlO₂ and enhancement of the mechanical strength during cell operation.     

A high capacity, template-electroplated Ni-Sn intermetallic electrode for lithium ion battery

In this paper we describe a Ni-Sn intermetallic material obtained via template electroplating synthesis. The structure and the morphology of this material are investigated by X ray diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. We demonstrate that Ni-Sn behaves as a sub-micrometric electrode showing a favourable response when cycled in a lithium cell. The results here reported suggest that the template electroplating is a promising synthetic approach that can lead to an optimized structure and morphology of the Ni-Sn electrode, such as to confer it a role of a high capacity anode in advanced lithium ion batteries.     

Proposed amendments to UN ST/SG/AC.10/11: transport of dangerous goods—lithium batteries

UN Document ST/SG/AC.10/11 [ST/SG/AC.10/11, The UN recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, 2nd revision] outlines a test plan that is fundamental to the classification for transport of lithium batteries with metallic lithium or lithium alloy anodes. Cells and batteries that fall within its scope are considered dangerous goods. The test plan requires amendment to address many shortcomings. Some tests assess risks that do not exist, other risks are not addressed. This paper outlines the issues we have identified with the test plan, the proposed amendments, the rationale behind the proposed amendments, and issues we have not addressed in the current round of amendments. Transport of lithium batteries has an excellent record. Packaging requirements are essential to continued safe transport. Tests that address known risks relevant to conditions normal to transport are discussed. It is for consideration that non-metallic anode systems such as some polymer and lithium-ion systems should be treated as distinctly different technologies with their own set of transportation risks. The use of the marketing term lithium battery when applied to lithium polymer and lithium-ion products has erroneously lead to the suggestion that they be included in the scope of UN Document ST/SG/AC.10/11. A recommendation to classify such systems under a new UN number is presented. It is suggested that UN 3090 or UN 3091 should be reserved for lithium metal or lithium metal alloy products.     

In situ detection of lithium dendrite in the failure of lithium-ion batteries

锂离子电池在应用过程中常出现一些失效现象如循环寿命缩短、自放电率变大、功率特性劣化等,甚至发生安全问题。负极析锂是导致这些失效甚至安全问题的主要因素之一,因此了解析锂的原因与过程就显得格外重要。探明析锂原因的关键是表征锂的存在和锂枝晶的生长过程。本文综述了锂离子电池负极析锂现象常用的原位检测技术,包括物理检测法和电化学法。物理检测法主要介绍：光学原位技术、原位X射线技术、原位核磁技术以及原位中子技术,电化学方法包含：充放电电压曲线法、Arrhenius法、内阻容量曲线分析法和容量衰减率法。本文针对物理检测法的原理、优缺点以及对应的特殊检测装置实例,电化学检测法的原理及分析方法等进行简要概述,并对目前析锂原位检测存在的问题进行总结及其研究方向进行展望。     

Pressure wave behavior and its effects on structure under In-box LOCA in a helium-cooled lead lithium blanket of hydrogen fusion reactors

The helium-cooled lead lithium (PbLi) blanket is considered as one of the candidate blanket concepts selected for the hydrogen fusion DEMO reactors and beyond, which has the advantages of simple structure, strong heat removal capacity and high tritium breeding ratio. However, due to the harsh environment such as high-energy neutron irradiation, high thermal load and great pressure gradient, there is a high possibility that one or some of the thousands of coolant channels will break in the breeding zone, which is so-called In-box Loss of Coolant Accident (In-box LOCA). When the accident occurs, the high pressure helium will rapidly inject into the lead lithium flow channel, generating a complex two-phase flow and great pressure shock effect, which may cause the peak pressure to exceed the design limit and threaten the integrity of the blanket structure. Therefore, it is of great significance to perform the transient analysis of in-box LOCA to improve the safety of the blanket and avoid the leakage of radioactive materials. In this paper, a two-way coupling model for fluid-solid interaction was established based on the ANSYS Workbench, and the model were validated through the experimental data obtained by injecting the high pressure helium gas into liquid lithium lead. Then the validated model was applied to the transient pressure wave propagation analysis and structural stress analysis of the Dual-Functional Lithium Lead (DFLL) blanket in order to explore the integrity of blanket structure under In-box LOCA. In addition, the effects of break location on pressure and structural stress was also investigated through six cases. The study found that the transient pressure in the DFLL blanket gone through three stages in any case: step rise, oscillate, and flatten out. Pressure peaks occurred during oscillations and their values were strongly dependent on the break location. The closer to the inlet/outlet, the higher the peak pressure was. The maximum pressure reached more than twice of the inlet pressure (up to ~16 MPa). As a result, the structural stress in some local areas has exceeded the allowable limits, and the corresponding suggestions for improvement have also been put forward. This study can provide guidance for safety design, operation and accident mitigation measures of helium-cooled lead lithium blankets.     

A new application of the UltraBattery to hybrid fuel cell vehicles

This study involves investigation of fuel cell hybrid vehicles. The main power source in the dynamic configuration is a proton exchange membrane fuel cell. An energy performance comparison is conducted between the use of a lithium‐ion battery (Automotive Energy Supply Corporation, Japan) and the UltraBattery (Furukawa Battery Company, Japan) as auxiliary power sources. The MATLAB/Simulink for simulation is used to observe dynamic behavior and overall performance. This study describes the simulation frameworks of the proton exchange membrane fuel cell, ultracapacitor, lead–acid battery, and UltraBattery. Then, the Economic Commission for Europe 40 driving cycle is used to test and investigate the performance of the fuel cell hybrid vehicle. Four energy output models are adopted to simulate the energy demand and the energy motor output of the dual power source, namely the high‐load demand, general demand, low‐load demand, and charge models. The simulation results indicate that the lithium battery recycles 0.1% more work compared with the UltraBattery. Regarding fuel economy, the UltraBattery is only 0.1% inferior to the lithium battery. The expected cost of an UltraBattery with the same specifications is 35% less than that of a lithium battery. Considering fuel economy and cost simultaneously, the UltraBattery can compete with the lithium battery. Copyright © 2015 John Wiley & Sons, Ltd.     

Lithium electrodes with and without CO2 treatment: electrochemical behavior and effect on high rate lithium battery performance

The ionic resistivity and integrity of a solid-electrolyte interphase (SEI) film on a lithium electrode surface was investigated. The performed lithium carbonate film on the surface of the lithium electrode was found to improve the electrode behavior by maintaining a low ionic resistance. In lithium/silver vanadium oxide batteries, voltage delay can be eliminated with the use of a lithium anode pretreated with CO₂. An SEI consisting of lithium carbonate appears to be responsible. Unlike the surface film formed from lithium-electrolyte reactions, the lithium carbonate film is relatively strong and can withstand high current density pulses (∼ 20 mA/cm²) without significant damage. An ion exchange mechanism involving the carbonate anion is proposed.     

Highly efficient lithium composite anode with hydrophobic molten salt in seawater

A lithium composite anode (lithium/1-butyl-3-methyl-imidazoleum hexafluorophosphate (BMI⁺PF₆⁻)/4-VLZ) for primary lithium/seawater semi-fuel-cells is proposed to reduce lithium–water parasitic reaction and, hence, increase the lithium anodic efficiency up to 100%. The lithium composite anode was activated when in contact with artificial seawater (3% NaCl solution) and the output was a stable anodic current density at 0.2 mA/cm², which lasted about 10 h under potentiostatic polarization at +0.5 V versus open circuit potential (OCP); the anodic efficiency was indirectly measured to be 100%. With time, a small traces of water diffused through the hydrophobic molten salt, BMI⁺PF₆⁻, reached the lithium interface and formed a double layer film (LiH/LiOH). Accordingly, the current density decreased and the anodic efficiency was estimated to be 90%. The hypothesis of small traces of water penetrating the molten salt and reaching the lithium anode—after several hours of operation—is supported by the collected experimental current density and hydrogen evolution, electrochemical impedance spectrum analysis, and non-mechanistic interface film modeling of lithium/BMI⁺PF₆⁻.     

Novel composite polymeric electrolytes with surface-modified inorganic fillers

Surface-modified inorganic powders were applied as additives to plain salt-in-polymer polymeric electrolytes in order to enhance their properties and make them applicable in all-solid-state Li-polymer primary and secondary cells. These fillers consisted of alumina and titania powders (coarse and nano-sized) with superacidic groups introduced onto their surface. Then they were added to low and high molecular weight poly(ethylene oxide) (PEODME 500 and PEO 4,000,000) together with lithium perchlorate (LiClO₄, lithium tetraoxochlorate(VII)). In this way several different composite electrolytes were obtained that exhibited excellent stability versus lithium metal electrode and high lithium transference number. Herein the preparation procedure is described and preliminary results given.     

Reaction mechanisms for the limited reversibility of Li-O2 chemistry in organic carbonate electrolytes

The Li-O₂ chemistry in nonaqueous liquid carbonate electrolytes and the underlying reason for its limited reversibility was systematically investigated. X-ray diffraction data showed that regardless of discharge depth lithium alkylcarbonates (lithium propylenedicarbonate (LPDC), or lithium ethylenedicarbonate (LEDC), with other related derivatives) and lithium carbonate (Li₂CO₃) are constantly the main discharge products, while lithium peroxide (Li₂O₂) or lithium oxide (Li₂O) is hardly detected. These lithium alkylcarbonates are generated from the reductive decomposition of the corresponding carbonate solvents initiated by the attack of superoxide radical anions. More significantly, in situ gas chromatography/mass spectroscopy analysis revealed that Li₂CO₃ and Li₂O cannot be oxidized even when charged to 4.6 V vs. Li/Li⁺, while LPDC, LEDC and Li₂O₂ are readily oxidized, with CO₂ and CO released from LPDC and LEDC and O₂ evolved from Li₂O₂. Therefore, the apparent reversibility of Li-O₂ chemistry in an organic carbonate-based electrolyte is actually an unsustainable process that consists of (1) the formation of lithium alkylcarbonates through the reductive decomposition of carbonate solvents during discharging and (2) the subsequent oxidation of these same alkylcarbonates during charging. Therefore, a stable electrolyte that does not lead to an irreversible by-product formation during discharging and charging is necessary for truly rechargeable Li-O₂ batteries.     

A hybrid power source with a shared electrode of polyaniline doped with LiPF6

We fabricated a hybrid power source device with three electrodes of which one was a LiPF₆-doped polyaniline (PAn) electrode playing the roles of both the positive electrode of a lithium secondary battery and an electrode of a redox supercapacitor. As a consequence, the shared electrode acts as a positive electrode or a positive terminal of a hybrid power source. The negative terminal was connected between a lithium metal electrode and another LiPF₆-doped PAn electrode. After characterizing and comparing this hybrid power source with a single lithium secondary battery, its discharge performance was superior to that of a single lithium secondary battery when adopting the sheet-type PAn-LiPF₆ electrodes and the porous separator as an electrolyte medium. In this case, the hybrid power source was shown to be advantageous in the high pulse mode of discharge.     

Fundamental scientific aspects of lithium ion batteries (XV) ——Summary and outlook

自摇椅式可充放锂电池概念由Armand M等人在1972年提出,锂离子电池的基础研究历经43年,在材料体系、电化学反应机理、热力学、动力学、结构演化、表界面反应、安全性、力学行为等方面不断取得更为深入广泛的认识,并最终推动锂离子电池技术发展和成功实现了商业化。锂离子电池面临着电池性能需要全面提升、应用领域需进一步拓宽的强劲需求,因此要求基础研究能够提供创新的、更好的技术解决方案,对锂离子电池材料复杂的构效关系能精确认识,对于电池在制造和服役过程中的失效机制有全面的理解,对各种控制策略的效果能提供可靠的科学依据。同时,锂离子电池的发展也在促进着固态电化学、固态离子学、能源材料、能源物理、纳米科学等交叉基础学科的发展。作为“锂离子电池基础科学问题”讲座的最后一篇文章,本文对锂离子电池基础研究的科学问题,存在的难点、发展趋势进行了总结。     

Superior electrode performance of mesoporous hollow TiO2 microspheres through efficient hierarchical nanostructures

Mesoporous hollow TiO₂ microspheres with controlled size and hierarchical nanostructures are designed from a process employing in suit template-assisted and hydrothermal methods. The results show that the hollow microspheres composed of mesoporous nanospheres possess very stable reversible capacity of 184 mAh g⁻¹ at 0.25C and exhibit extremely high power of 122 mAh g⁻¹ at the high rate of 10C. The superior high-rate and high-capacity performance of the sample is attributed to the efficient hierarchical nanostructures. The hollow structure could shorten the diffusion length for lithium ion in the microspheres. The large mesoporous channels between the mesoporous nanospheres provide an easily-accessed system which facilitates electrolyte transportation and lithium ion diffusion within the electrode materials. The electrolyte, flooding the mesoporous channels, can also lead to a high electrolyte/electrode contact area, facilitating transport of lithium ions across the electrolyte/electrode interface. The small mesopores in the meosporous nanospheres can make the electrolyte and lithium ion further diffuse into the interior of electrode materials and increase electrolyte/electrode contact area. The small nanoparticles can also ensure high reversible capacity.     

Chelate complexes with boron as lithium salts for lithium battery electrolytes

The electrolytic conductivity and charge–discharge characteristics of lithium electrodes are examined in propylene carbonate (PC)- and ethylene carbonate (EC)-based binary solvent electrolytes containing lithium bis[1,2-benzenediolato(2-)-O,O′]borate (LBBB), lithium bis[2,3-naphthalenediolato(2-)-O,O′]borate (LBNB) and lithium bis[2,2′-biphenyldiolato(2-)-O,O′]borate (LBBPB). The LBBPB exhibits high thermal and electrochemical stability compared with LBBB and LBNB. Conductivities in PC-THF and EC-THF binary solvent electrolytes at XTHF (mole fraction of tetrahydrofuran, THF)=0.5 containing 0.5 M LBBB and LBNB are nearly equal to that in 0.5 M LiCF₃SO₃ electrolyte as a typical lithium battery electrolyte. The conductivity in 0.3 M LBBPB/PC-DME (DME: 1,2-dimethoxyethane) electrolyte is fairly low compared with that in other electrolytes. The energy density with the LBNB electrolyte is higher than that with LBBB or LBBPB electrolyte. In general, lithium cycling efficiencies in THF-based LBBB and LBNB electrolytes become higher than those in DME-based electrolytes. The 0.5 M LBNB/PC-THF electrolyte is a moderately rechargeable lithium battery electrolyte. The 0.3 M LBBPB/PC-DME equimolar solvent electrolyte displays the highest cycling efficiency, viz., >70%, at a high range of cycle number.     

Novel lithium titanate hydrate nanotubes with outstanding rate capabilities and long cycle life

Novel lithium titanate hydrate nanotubes for lithium ion batteries have been easily prepared via a hydrothermal method. This material demonstrates high energy density, outstanding rate capabilities and a very long cycle life comparable to those of supercapacitors. At a rate equivalent to a 10-min total charge/discharge, the as-prepared lithium titanate hydrate nanotubes exhibit a life of over 5000 charge/discharge cycles while still retaining up to 86.3% of its original capacity. The abilities of lithium titanate hydrate nanotubes to fully charge within minutes for thousands of times and still retain a large capacity may find promising applications in hybrid and plug-in hybrid electric vehicles.     

全固态薄膜锂电池研究进展

同锂离子电池相比,全固态锂电池不仅安全性好,而且在提高比能量、比功率密度以及循环性能方面也有更大的空间,从而得到广泛关注。在现有全固态锂电池中全固态薄膜锂电池（TFB）的制备工艺成熟,电池性能优异,已率先实现了商品化生产。同传统的锂离子电池不同,TFB的主要制备方法是物理成膜形成致密正极、电解质和负极薄膜,各层薄膜采用原位叠加方式形成。本文总结了近十年来TFB的研究工作,力图囊括全固态薄膜电池的完整制备过程以及各制备环节的技术进展和存在的科学技术问题。本文首先分述了固态电解质薄膜、正极薄膜、负极薄膜等三个主要构成部分的研究进展和关键问题,在此基础上,归纳了电极/电解质界面的设计、制备以及TFB制备过程及其关键问题和技术的研究进展,最后还介绍了基底、集流体、封装三个辅助部分的制备过程以及最近报道的新型特殊结构TFB。     

Fine-tuning the fluorescent properties of Li and Na intercalated C60 with hydrogen

In this work we demonstrate how hydrogen can be utilized to fine tune the emission gap of C₆₀ through the formation of direct CH bonds in sodium and lithium intercalated systems (M₆C₆₀H_x). Upon hydrogenation, a shift in the emission spectrum to shorter wavelengths (higher energy) is observed relative to alkali metal free fulleranes (C₆₀H_x) and pure C₆₀. This is attributed to the higher degree of hydrogenation of C₆₀ that can be achieved upon intercalation with alkali metals which increases the sp³ hybridization of the system (decreases conjugation). Quantum yields of the sodium and lithium intercalated fulleranes are 1.3% and 1.8% respectively which are similar to those of alkali metal free fulleranes (1.4%). We also show that polymethyl methacrylate (PMMA) can be infused with the metal intercalated fulleranes to produce a fluorescent polymer with excellent transparency over the visible spectrum. This could potentially lead to further use of these materials in luminescent down shifting applications.