非水体系锂-空气电池研究进展

锂-空气电池是目前已知具有最高能量密度的二次电池,有望成为未来电动汽车的动力电源。由于其能量密度高、环境友好以及成本较低,成为广大科研工作者研究的热点,在过去二十年间与之有关的研究已经在反应机理、电极结构、催化剂及电解液等各方面都取得了很大进展,但受诸多因素限制,其实用化仍然任重道远。本文总结了近几年来非水体系锂-空气电池在反应机理、正极材料、催化剂、电解液以及锂负极等方面的最新研究进展,并在此基础上展望其未来的发展方向。     

锂嵌入型化合物-氢气电池（英文）

可充电氢气电池作为一种新兴的电池体系在大规模能源储存领域显示出富有前景的电化学性能.锂嵌入型化合物作为一大类的锂离子电池正极材料能够很好地用作可充电氢气电池的正极.本文开发了2种新型锂嵌入型化合物-氢气电池.通过使用钴酸锂与磷酸铁锂2种正极材料分别与氢气负极在硫酸锂水系电解液中进行匹配,得到了钴酸锂-氢气电池与磷酸铁锂-氢气电池.钴酸锂-氢气电池展现出约1.27 V的放电电位,约97 mA·h·g~(-1)的比容量及10C的高倍率;磷酸铁锂-氢气电池展现出约0.66 V的放电电位,约125 mA·h·g~(-1)的比容量以及10C的高倍率.虽然,钴酸锂-氢气电池和磷酸铁锂-氢气电池因为使用了未经优化的、不稳定的锂嵌入型化合物正极材料而导致全电池容量衰减,但这2种电池经过氢气负极的再循环利用均表现出优异的恢复能力.本文结果证明了氢气电池的化学稳定性及其在未来长寿命电池中具有的大规模能源储存潜力.     

多酚类化合物—丹宁酸用作锂金属负极电解液成膜添加剂

As the application of lithium-ion batteries in advanced consumer electronics, energy storage systems, plug-in hybrid electric vehicles, and electric vehicles increases, there has emerged an urgent need for increasing the energy density of such batteries. Lithium metal anode is considered as the "Holy Grail" for high-energy-density electrochemical energy storage systems because of its low reduction potential (-3.04 V vs standard hydrogen electrode) and high theoretical specific capacity (3860 mAh·g^-1). However, the practical application of lithium metal anode in rechargeable batteries is severely limited by irregular lithium dendrite growth and high reactivity with the electrolytes, leading to poor safety performance and low coulombic efficiency. Recent research progress has been well documented to suppress dendrite growth for achieving long-term stability of lithium anode, such as building artificial protection layers, developing novel electrolyte additives, constructing solid electrolytes, using functional separator, designing composite electrode or three-dimensional lithium-hosted material. Among them, the use of electrolyte additives is regarded as one of the most effective and economical methods to improve the performance of lithium-ion batteries. As a natural polyphenol compound, tannic acid (TA) is significantly cheaper and more abundant compared with dopamine, which is widely used for the material preparation and modification in the field of lithium-ion batteries. Herein, TA is first reported as an efficient electrolyte film-forming additive for lithium metal anode. By adding 0.15% (mass fraction, wt.) TA into the base electrolyte of 1 mol·L^-1 LiPF₆-EC/DMC/EMC (1 : 1 : 1, by wt.), the symmetric Li|Li cell exhibited a more stable cyclability of 270 h than that of only 170 h observed for the Li|Li cell without TA under the same current density of 1 mA·cm^-2 and capacity of 1 mAh·cm^-2 (with a cutoff voltage of 0.1 V). Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), and energy-dispersive X-ray spectroscopy (EDS) analyses demonstrated that TA participated in the formation of a dense solid electrolyte interface (SEI) layer on the surface of the lithium metal. A possible reaction mechanism is proposed here, wherein the small amount of added polyphenol compound could have facilitated the formation of LiF through the hydrolysis of LiPF₆, following which the resulting phenoxide could react with dimethyl carbonate (DMC) through transesterification to form a cross-linked polymer, thereby forming a unique organic/inorganic composite SEI film that significantly improved the electrochemical performance of the lithium metal anode. These results demonstrate that TA can be used as a promising film-forming additive for the lithium metal anode.     

锂-硫电池研究现状及展望

锂-硫电池由于具有高比能量以及硫廉价易得等优势而受到人们的广泛关注. 但其实际应用仍面临着来自于正极、电解液以及负极等方面的诸多挑战,具体包括硫正极的溶解、多硫化合物的“穿梭效应”及金属锂负极的枝晶问题. 本文以课题组近期的研究结果为主线,综述了近两年来关于锂-硫电池的研究进展,重点探讨了碳硫复合物正极、硫化锂正极、复合隔膜设计和电解液方面的研究进展,并总结了各方面存在的问题.     

锂硫电池结构设计研究现状及展望

锂硫电池体系由于理论能量密度高和硫材料资源丰富,成为了极具发展潜力的二次电池之一.但由于放电过程中间产物多硫化物溶于有机电解液,产生穿梭效应,导致活性物质利用率低,造成电池容量损失和循环性能下降,而锂金属枝晶和界面问题同样限制了锂硫电池的进一步发展和利用.研究表明,电池结构设计和改造,如隔膜结构设计、正极夹层设计、正极载硫结构设计以及负极结构设计等方面,有效地缓解了上述问题.本文整理总结了近年来国内外在锂硫电池结构设计上研究思路和进展,并对今后的发展趋势做了进一步展望.     

非水溶剂Li-O2电池锂负极研究进展

The aprotic Li-O₂ battery has attracted considerable interest in recent years because of its high theoretical specific energy that is far greater than that achievable with state-of-the-art Li-ion technologies. To date, most Li-O₂ studies, based on a cell configuration with a Li metal anode, aprotic Li⁺ electrolyte and porous O₂ cathode, have focused on O₂ reactions at the cathode. However, these reactions might be complicated by the use of Li metal anode. This is because both the electrolyte and O₂ (from cathode) can react with the Li metal and some parasitic products could cross over to the cathode and interfere with the O₂ reactions occurring therein. In addition, the possibility of dendrite formation on the Li anode, during its multiple plating/stripping cycles, raises serious safety concerns that impede the realization of practical Li-O₂ cells. Therefore, solutions to these issues are urgently needed to achieve a reversible and safety Li anode. This review summarizes recent advances in this field and strategies for achieving high performance Li anode for use in aprotic Li-O₂ batteries. Topics include alternative counter/reference electrodes, electrolytes and additives, composite protection layers and separators, and advanced experimental techniques for studying the Li anode|electrolyte interface. Future developments in relation to Li anode for aprotic Li-O₂ batteries are also discussed.     

有机硫化合物在锂硫电池中的应用

锂硫电池具有理论能量密度高、环境友好和成本低等优点,有望成为替代锂离子电池的新一代储能系统。然而,锂硫电池充放电产物的绝缘性、可溶性多硫化锂的穿梭效应、硫正极体积膨胀及锂枝晶的不可控生长,严重影响了锂硫电池的实际容量发挥和循环稳定性。为解决上述问题,采用有机硫化合物来替代单质硫作为正极材料是有前途的策略。调控有机硫化合物的硫链、碳链及其相互作用,可改变其电化学反应过程,提高离子/电子电导,抑制穿梭效应。有机硫化合物作为电解液添加剂,可调控硫正极的反应过程并保护金属锂负极,作为聚合物电解质的改性链段可加速锂离子传导。本综述对有机硫化合物在锂硫电池的正极、电解液添加剂和固态电解质中的应用研究进展进行详细的阐述。将有机硫化合物的结构、反应机理和电化学性质联系起来,为解决锂硫电池存在的问题提供见解。最后,提出高性能有机硫化合物的设计合成和机理研究思路,以期实现可实用化的锂硫电池。     

锂硫电池电解质研究进展

锂硫电池由于其高能量密度(理论高达2600 Wh/kg)、低成本、环境友好等优点而广受关注. 但是锂硫电池仍存在正极活性物质利用率低、循环性能差等问题. 造成这些问题的主要原因是易溶于有机电解液的中间产物聚硫锂Li₂S_n (4≤n≤8)和不溶于有机电解液的硫化锂造成的. 简要介绍了锂硫电池体系的主要问题,并结合本研究小组的研究,对锂硫电池用电解质体系从有机电解液组成、电解液添加剂、聚合物电解质和无机固体电解质等方面进行了详细的综述,最后对电解质的发展前景进行了展望.     

锂氧电池关键技术研究

锂氧电池是一种用金属锂作负极,以氧气作为正极反应物的金属空气电池,由于其具备较高的理论比能量且环境友好等优势,近年来开始备受关注。本文主要概述了锂氧电池关键技术的最新研究进展,包括正极材料、催化剂、电解质、负极及电池结构等,并在此基础上对其未来发展趋势进行了展望,以期对其他金属空气电池的研究提供新思路和手段。     

高性能锂硫电池研究进展

锂硫电池具有理论比容量高(1675 m Ah·g~(-1))、能量密度高(2600 Wh·kg~(-1))、环境友好、价格低廉等性质,是一种高性能的新型储能电池。这些性能使其在电动汽车和便携式设备领域具有重要意义。然而,快速的容量衰减以及较差的循环性能,使锂硫电池还达不到商业应用的要求。本文全面总结了锂硫电池的最新研究进展,详细阐述了锂硫电池的正极、电解质、隔膜以及负极保护,分析了现有锂硫电池存在的缺陷和问题。最后,对锂硫电池未来的发展方向进行了展望。     

Electrochemical Performance of LiMn2O4/LiFePO4 Blend Cathodes for Lithium Ion Batteries

A series of LiMn₂O₄/LiFePO₄ blend cathodes was prepared by hand milling and ball milling in order to compensate the disadvantage of spinel LiMn₂O₄ and olivine LiFePO₄. The morphologies of the blends were studied by scanning electron microscopy, and their electrochemical properties were studied by charge-discharge cycling, cyclic voltammetry and electrochemical impedance spectroscopy. It is easy to obtain uniform LiMn₂O₄/LiFePO₄ blends by the hand milling technique, while significant particle agglomeration is caused by the ball milling technique. When the LiMn₂O₄:LiFePO₄ mass ratio is 1:1, the nano-sized LiFePO₄ powders not only uniformly cover the micron-sized LiMn₂O₄ particles but also effectively fill in the cavities of the LiMn₂O₄ space. Such morphology offers a good electrical contact and a high tap density, which leads to a high discharge capacity and good cycle stability.     

二次锂电池用离子液体电解质研究

合成了哌啶类离子液体N-甲基-N-丙(丁)基哌啶三氟甲基磺酰亚胺[PP13(4)-TFSI], 并与现在常用的两种离子液体1-丁基-3-甲基-咪唑六氟磷酸(BMIPF₆)及1-丁基-3-甲基-咪唑四氟硼酸(BMIBF₄)进行了各种电化学性能的对比. PP13(4)-TFSI的电化学稳定窗口可以达到5.8 V, 明显大于BMIBF₄ (4.7 V) 以及BMIPF₆ (4.6 V). 而且PP13(4)-TFSI负极极限电位(－0.3 V vs. Li/Li^＋)明显低于BMIPF₆ (0.5 V) 和BMIBF₄ (0.7 V), 有望被使用在以锂金属作为负极的二次锂电池中. 以LiTFSI /PP14-TFSI为电解质溶液测试了Li/LiCoO₂纽扣电池的电化学性能, 在0.05 mA•cm^－2的恒定电流充放电条件下, 电池的比容量可以达到150 mAh•g^－1, 初始循环以后库仑效率接近100%. 交流阻抗测试表明, 电池的阻抗特性稳定, 不存在明显的界面钝化现象.     

Nickel hydrogen gas batteries: From aerospace to grid-scale energy storage applications

The challenging requirements of high safety, low-cost, all-climate and long lifespan restrict most battery technologies for grid-scale energy storage. Historically, owing to stable electrode reactions and robust battery chemistry, aqueous nickel–hydrogen gas (Ni–H₂) batteries with outstanding durability and safety have been served in aerospace and satellite systems for over three decades ever since their first development in the 1970s. Despite their satisfactory performances, this technology has difficulty to be applied for grid-scale energy storage primarily because of their high cost resulting from the utilization of expensive platinum as anode hydrogen catalyst. In recent years, with the extensive exploration of inexpensive hydrogen evolution/oxidation reaction catalysts, advanced Ni–H₂ batteries have been revived as promising battery chemistry for grid-scale energy storage applications. This mini-review provides an overview of the development activities of Ni–H₂ batteries and highlights the recent advances in the application of advanced Ni–H₂ batteries for grid-scale energy storage. New cost-effective hydrogen evolution/oxidation reactions catalysts, novel cathode materials, and advanced Ni–H₂ battery designs toward further development of Ni–H₂ batteries are discussed. The renaissance of advanced Ni–H₂ battery technology is particularly attractive for future grid-scale energy storage applications.     

锂金属负极界面修饰及其在硫化物全固态电池中的应用

随着我国新能源产业的快速发展,全固态电池由于其理论上的高能量密度和高安全性受到广泛关注,而硫化物全固态电池具有离子电导率高的优势成为目前的研发热点,但是金属锂负极的锂枝晶生长和与硫化物电解质之间的不稳定性严重阻碍了硫化物全固态电池的研发.本工作在高温150℃下制备了均匀的LiF界面层来抑制金属锂负极/硫化物电解质之间的界面反应和锂枝晶.LiF/Li之间具有较高的界面能,所以可以有效抑制锂枝晶的生长.LiNbO₂@LiCoO₂//Li₆PS₅Cl//LiF@Li (LNO@LCO//LPSCl//LiF@Li)全电池0.05 C, 0.1 C, 0.2 C和0.5 C倍率的正极放电克容量分别为138.4 mAh/g, 105.0 mAh/g, 80.3 mAh/g和60.4 mAh/g, 0.05 C循环50周后,正极容量保持率为80.2%.该方法为后续金属锂负极在全固态电池中的应用提供了新的方案.     

用于可充锂电池的高倍率磷酸铁(II)锂正极材料

本文以聚氧化乙烯为碳源,用柠檬酸辅助湿化学法合成了高倍率的碳包覆的LiFePO₄。使用热重、粉末X射线衍射、扫描电子显微镜、透射电子显微镜、循环伏安、电化学阻抗和恒流充放电表征材料的结构和电化学性质。结果表明,该材料组成为5 wt%疏松多孔的碳包覆相纯度很高的小的LiFePO₄颗粒。该材料适用于高倍率充放电,在5 C、10 C和20C的放电倍率下可以分别得到120、90和60 mAh·g^-1的稳定容量。     

增塑剂对聚合物电解质锂离子电池性能的影响

锂电子;碳纤维;增塑剂对聚合物电解质锂离子电池性能的影响     

以LiCoO2为阴极的全固态薄膜锂电池的研究

Amorphous and oriented polycrystalline LiCoO2 thin films, used as cathode material for an all-solid-state thin film battery, were fabricated by using RF magnetron sputtering and annealed at different temperatures. The morphology and structure of LiCoO2 thin films were characterized by scanning electron microscopy and X-ray diffraction. All-solid-state thin film batteries, comprised of LiCoO2 cathode films with different structures, lithium phosphorous oxynitride electrolyte film and metallic lithium anode film, was successfully prepared and their properties were examined by chronopotentiometry. Results showed that the structure and crystallinity of the LiCoO2 films strongly influenced the electrochemical performance of all-solid-state thin film lithium batteries. Worth nothing was the battery with an oriented polycrystalline LiCoO2 film it exhibited the best electrochemical performance, and delivered a discharge capacity of ～55.4 μAh/cm2μm. Furthermore, when subjected to over 450 charge/discharge cycles, that battery suffered no obvious fode in capacity.     

高性能LiFePO4/碳纳米笼锂离子电池正极材料

以具有高比表面积、分级孔结构和优良导电性的碳纳米笼（CNCs）为载体,制得了粒子尺寸为10～25 nm且高度分散的LiFePO₄/CNCs复合物.以LiFePO₄/CNCs复合物作为锂离子电池的正极材料,在0.1 C倍率下首次放电比容量达到163 mAh·g^-1,15 C和30 C倍率下的放电比容量可达96和75 mAh·g^-1;在15 C倍率下循环200圈后,其放电比容量仍保持在92 mAh·g^-1,显著优于LiFePO₄/CNTs复合物.这些结果表明,LiFePO₄/CNCs复合物具有优异的倍率性能和循环稳定性,是一种性能优良的锂离子电池正极材料,其性能源自CNCs载体的高比表面积、分级孔结构和优异导电性以及LiFePO₄颗粒的纳米化和高结晶度.     

磷酸铁锂表面碳包覆研究进展

橄榄石结构的LiFePO₄具有电压平台平稳、价格低廉、原料丰富和环境友好等优点,得到了人们的广泛关注. 然而,纯LiFePO₄的离子和电子导电性较差,其大范围应用受限. 研究表明,对LiFePO₄表面进行碳包覆可以有效提升其电化学性能. 结合国内外研究现状,本文综述了不同的碳包覆方法、碳源种类对LiFePO₄电化学性能的影响,以及碳包覆提升LiFePO₄正极材料电化学性能的作用机制.     

Mechanism of Lithium and Cobalt Recovery from Spent Lithium-ion Batteries by Sulfation Roasting Process

Different from the traditional pyrometallurgical recovery process of Li and Co from spent lithium-ion batteries, a new recovery method for Li and Co was established by converting LiCoO₂ into water-soluble metal sulfates by roasting a mixture of LiCoO₂ and NaHSO₄·H₂O. The evolution law of the mixture with increased roasting temperature was investigated by thermogravimetry-differential scanning calorimetry(TG-DSC), in situ X-ray diffraction(XRD), XRD, and X-ray photoelectron spectroscopy(XPS). The results show that the phase transition of LiCoO₂ mixed with NaHSO₄·H₂O with increased temperature proceeded as follows:LiCoO₂, NaHSO₄·H₂O→LiCoO₂, NaHSO₄→Li_1-xCoO₂, LiNaSO₄, Na₂S₂O₇, Na₂SO₄→Li_1-xCoO₂, Co₃O₄, LiNaSO₄, Na₂SO₄→Co₃O₄, LiNaSO₄. The reaction mechanism of this roasting process may be as follows:LiCoO₂+NaHSO₄·H₂O→1/2Li₂SO₄+ 1/2Na₂SO₄+1/3Co₃O₄+1/12O₂+3/2H₂O, Li₂SO₄+Na₂SO₄=2LiNaSO₄.