锂离子电池高比容量FeSn2-C复合负极材料的合成与性能

Sn基合金负极材料具有高达990 mAh·g^-1的理论比容量,但其也存在因脱嵌锂过程发生巨大的体积变化而导致循环性能较差的问题. 本文以Sn、Fe、石墨为原料利用简易的高能球磨法成功制备了具有核壳结构的FeSn₂-C复合物,系统研究了球磨时间、FeSn₂相含量对材料物相结构及电化学性能的影响,并分析了电极的失效机理. 研究表明,球磨时间的增加有利于FeSn₂金属间化合物相的形成及材料颗粒的细化,进而有利于材料比容量的增加及循环性能的提升;FeSn₂相含量的增加能够提高FeSn₂-C材料的比容量,但会降低FeSn₂-C电极的循环稳定性. 经工艺优化及组分调节,球磨24 h合成的Sn₂₀Fe₁₀C₇₀材料具有最优的电化学性能,材料的比容量在540 mAh·g^-1左右,并能稳定循环100次,是一种非常有发展前途的锂离子电池高比容量负极材料.     

锂离子电池用多孔硅/石墨/碳复合负极材料的研究

在两步高能球磨和酸蚀条件下制得了多孔硅/石墨复合材料，并对其进行碳包覆制成多孔硅/石墨/碳复合材料。通过TEM，SEM等测试手段研究了多孔硅材料的结构。作为锂离子电池负极材料，电化学测试结果表明多孔硅/石墨/碳复合材料相比纳米硅/石墨/碳复合材料有更好的循环稳定性。同时，改变复合体配比、热解碳前驱物、粘结剂种类和用量也会对材料的电化学性能产生较大的影响。其中使用质量分数为10％的LA132粘结剂的电极200次循环以后充电容量保持在649.9 mAh·g^-1，几乎没有衰减。良好的电化学性能主要归因于主活性体-多孔硅颗粒中的纳米孔隙很好地抑制了嵌锂过程中自身的体积膨胀，而且亚微米石墨颗粒和碳的复合也减轻了电极材料的体积效应并改善了其导电性。     

BaFeSi/C复合物作为锂离子电池负极材料的研究

采用机械球磨法制备BaFeSi/C复合物,并考察了其作为锂离子电池负极材料的电化学性能.结果表明,这种复合材料具有较高的初始放电容量、合适的充放电平台和良好的循环可逆性.XRD和XPS研究证明:BaFeSi/C复合物循环性能的提高主要源于惰性导电组分FeSi2、BaSi2和外层石墨骨架的协同作用,它们的存在不仅有效地缓冲了活性组分硅的体积变化,同时在很大程度上增强了复合材料的电子导电性和离子导电性.     

锂离子电池负极材料SnO2的形貌调控合成

SnO₂是一种重要的宽禁带半导体材料,由于具有较高的理论容量,将其作为锂离子电池的负极材料有广阔的应用前景。材料的微观形貌对其物理化学性能有重要的影响作用,因此近年来大量的研究工作围绕SnO₂的形貌调控合成开展。本文综述了作为锂离子电池负极材料SnO₂的各种形貌的调控合成,如颗粒状、片状、一维、空壳、分级结构等,以及其形貌对电化学性能的影响,分析总结了各种形貌对其电化学性能的影响规律以及形貌调控的发展趋势。     

锂离子电池TiO2纳米管负极材料

锂离子电池负极材料二氧化钛(TiO₂)由于其零应变、环境友好和高安全性近年来得到了广泛的研究,但其较低的电子电导和离子迁移率以及较低的比容量(335 mAh·g^-1)限制了其应用前景.本文梳理了一种纳米结构TiO₂纳米管(TNTs)的研究历程以及最近研究进展,综述了TNTs常见的几种制备方法,即水热法、阳极氧化法和模板法及其形成机理,归纳了各种制备方法的优缺点,讨论了制备过程中各项参量对制得TNTs的影响.阐述了其晶体结构与形貌对电化学性能的影响,指出晶格取向一致、管壁厚度小,纳米管开口且同向排列的TNTs具有更好的电化学性能.同时探讨了针对该材料电导性差、比容量低而进行的包括结构设计、掺杂、复合等一系列改进措施,指出与高电导率及高比容量材料复合是一种方便有效的改进措施.最后总结了各种改性方法取得的进展及存在的不足,展望了TNTs的研究趋势和发展前景.     

可逆高储锂的锂离子电池炭负极材料的研究进展

对近几年所研究的高能可储锂炭材料进行了综述。主要为以下几个方面：石墨的改性、有机裂解炭、低温聚合物裂解炭和其它炭材料。     

锂离子电池负极硅基材料

硅基材料由于其高电化学容量是一种非常有发展前途的锂离子电池负极材料,但其在充放电过程中体积变化大、循环寿命差、首次库仑效率低等是阻碍其商业化的主要问题.本文综述了硅在脱嵌锂时晶体结构及表/界面的变化,以及改善其电化学性能方面的研究进展,并阐述其作为锂离子电池负极材料的研究前景.     

锂离子电池负极材料Cu2O的制备及电化学性能

采用多元醇法,以丙三醇、氢氧化钠、硫酸铜为原料,在油浴中共热制备Cu2O．通过X射线衍射分析（XRD）和电化学测试对材料进行了表征．结果表明,丙三醇能够将Cu^2＋还原为Cu^＋．并且,采用该方法制备出的Cu2O材料作为锂电池负极材料,具备较好的循环性能．     

硅基锂离子电池负极材料

硅是目前已知比容量(4200 mAh ·g^-1)最高的锂离子电池负极材料,但由于其巨大的体积效应(> 300%),硅电极材料在充放电过程中会粉化而从集流体上剥落,使得活性物质与活性物质、活性物质与集流体之间失去电接触,同时不断形成新的固相电解质层(SEI),最终导致电化学性能的恶化。本文介绍了硅作为锂离子电池负极材料的储能及容量衰减机理,总结了通过硅材料的选择和结构设计来解决充放电过程中巨大体积效应的相关工作,并讨论了一些具有代表性的硅基复合材料的制备方法、电化学性能和相应机理,重点介绍了硅炭复合材料。另外,介绍了一些电极的处理方法和其提高硅基负极材料电化学性能的可能机理。最后,对硅基负极材料存在的问题进行了分析,并展望了其研究前景。     

等离子体辅助球磨Si-C复合负极材料及其电化学性能研究

首次采用介质阻挡放电等离子体辅助高能两次球磨制得Si-C复合材料,其结构为微纳尺度硅颗粒均匀分散于微米级碳基体上. Si-C复合电极首周期循环放电容量为1259 mAh·g^-1,20和100周期循环的容量分别为474和396 mAh·g^-1. 该电极充放电曲线和交流阻抗测试的结果表明,复合材料中的硅和碳均参与锂离子嵌/脱反应,且其电荷传导阻抗明显低于纯Si.     

SnO_2/中空洋葱状碳纳米复合材料的制备及电化学性能

以炭黑为原料,硝酸铁为催化剂前驱体,氮气气氛下1000℃高温炭化制备了直径为40nm的中空洋葱状碳纳米颗粒(OC).用SnCl2/乙醇溶液浸渍,空气中350℃氧化得到SnO2/OC复合材料.进一步对该复合材料进行酸处理制备OC包覆的SnO2电极材料.采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和热失重分析(TGA)对OC和SnO2/OC复合材料进行表征;利用恒电流充放电和循环伏安(CV)方法对复合材料作为锂离子电池负极材料的电化学性能进行表征.结果表明:酸处理后的复合材料的循环性能得到明显改善,50次循环后可逆容量保持为446mAh·g-1,OC起到了缓冲SnO2膨胀和阻止团聚的作用.     

纳米MnO锂离子电池负极材料的制备与性能

以高锰酸钾和抗坏血酸合成的MnC₂O₄·2H₂O为前驱体, 通过固相烧结制备了纳米MnO材料. 分别采用X射线衍射(XRD)、扫描电子显微镜(SEM)和恒电流充放电技术考察了其晶相结构、颗粒形貌和电化学性能.分析结果表明, 该纳米MnO具有面心立方的岩盐结构, 结晶度良好. 其颗粒是由粒径为50-100 nm的一次颗粒结合而成的二次颗粒, 大小约为400-600 nm. 当充放电电流密度为46.3 mA·g^-1时, 纳米MnO的首次库仑效率可达68.9%, 可逆比容量为679.7 mAh·g^-1. 在141.1 mA·g^-1的电流密度下循环50圈后, 比容量由584.5mAh·g^-1降至581.5 mAh·g^-1, 容量保持率高达99.5%, 表现出优异的循环性能. 此外, 当电流密度增加到494.7 mA·g^-1 (~2C)时, 其比容量依然可达290 mAh·g^-1, 表现出较好的倍率性能和快速充放电能力. 因此, 纳米MnO具有比容量高、循环稳定、倍率性能好和安全环保等优点,是一种非常有前景的锂离子电池负极材料.     

NaTiSi2O6/C复合材料用于锂离子电池负极材料

The development of human society and the continuously emerging environmental problems call for cleaner energy resources. Lithium-ion batteries, since their commercialization in the early 1990s, have been an important power source of mobile phones, laptops as well as other portable electronic devices. Their advantages include environment-friendliness, light weight, and no memory effect compared with lead-acid or nickel-cadmium batteries. Electrode materials play an important role in the performance of lithium-ion batteries. The traditional commercial anode material, graphite, has a theoretical specific capacity of 372 mAh·g^-1 and working potential close to 0 V (vs Li⁺/Li), making it prone to the formation of lithium dendrite, which may cause short circuit especially when large current is applied. Another commercial anode material Li₄Ti₅O₁₂, which also undergoes an intercalation reaction during lithiation process, has a theoretical specific capacity of 175 mAh·g^-1 along with three lithium-ion intercalations per formula unit. This is relatively small, and it has a relatively high working potential of 1.55 V (vs Li⁺/Li), which reduces its output voltage and specific energy when assembled in full battery. To overcome the shortcomings mentioned above, it is essential to search for new anode materials that are low-cost, environment-friendly, and easy to synthesize. Silicate materials have gained widespread attention owing to their low cost and facile synthesis. Herein, we report for the first time a novel titanosilicate, NaTiSi₂O₆, synthesized by sol-gel and solid sintering. It is isostructural to pyroxene jadeite NaAlSi₂O₆, belonging to monoclinic crystal system with a space group of C2/c. By in situ pyrolysis and carbonization of glucose, nanosized NaTiSi₂O₆ mixed with carbon was successfully obtained with a specific surface area of 132 m²·g^-1, calculated according to the Brunauer–Emmett–Teller formula. The specific charge/discharge capacity in the first cycle at current density of 0.1 A·g^-1 is 266.6 mAh·g^-1 and 542.9 mAh·g^-1, respectively, with an initial coulombic efficiency of 49.1%. After 100 cycles, it retains a specific charge capacity of 224.1 mAh·g^-1, corresponding to a capacity retention rate of 84.1%. The average working potential of NaTiSi₂O₆ is 1.2–1.3 V (vs Li⁺/Li), slightly lower than that of Li₄Ti₅O₁₂. The reaction mechanism while charging and discharging was determined by in situ X-ray diffraction test as well as selected area electron diffraction. The results showed that NaTiSi₂O₆ undergoes an intercalation reaction during lithiation process, with two lithium-ion intercalations per formula unit. This makes NaTiSi₂O₆ a new member of the silicate anode material family, and may provide insights into the development of new silicate electrode materials in the future.     

多壁纳米碳管约束二硫化锡作为锂离子电池负极的电化学行为

通过两步法制备多壁纳米碳管约束SnS_2纳米材料(SnS_2@MWCNT)。采用直流电弧等离子体法在甲烷气氛下制备多壁纳米碳管约束金属锡纳米结构(Sn@MWCNT)作为前驱体,再通过硫化反应获得SnS_2@MWCNT纳米结构。对材料进行Raman、X射线衍射(XRD)、透射电镜(TEM)等物理表征的结果显示多壁纳米碳管长约400nm,表面碳层晶化程度良好,碳层厚度约10 nm。以Sn S2@MWCNT纳米结构作为负极材料的锂离子电池显示出较为良好的电化学性能。其首次充放电库伦效率为71%,循环50次后,容量仍保持703 mAh?g~(-1)。SnS_2@MWCNT纳米结构电极的高容量特性源于多种活性物质共同提供容量,且各物质反应平台不同。平台呈现明显阶梯型,缓解了体积膨胀效应对电极材料的破坏。     

The Status of Representative Anode Materials for Lithium-Ion Batteries

Since the invention of lithium-ion batteries as a rechargeable energy storage system, it has uncommonly promoted the development of society. It has a wide variety of applications in electronic equipment, electric automobiles, hybrid vehicles, and aerospace. As an indispensable component of lithium-ion batteries, anode materials play an essential role in the electrochemical characteristics of lithium-ion batteries. In this review, we described the development from lithium-metal batteries to lithium-ion batteries in detail on the time axis as the first step; This was followed by an introduction to several commonly used anode materials, including graphite, silicon, and transition metal oxide with discussions the charge-discharge mechanism, challenges and corresponding strategies, and a collation of recent interesting work; Finally, three anode materials are summarized and prospected. Hopefully, this review can serve both the newcomers and the predecessors in the field.     

Synthesis of SnS2 Ultrathin Nanosheets as Anode Materials for Potassium Ion Batteries

Potassium(K)ion batteries present their promising application for large-scale energy storage systems with cost-effective characteristic.Unfortunately,the large K ion radius results in sluggish K ion diffusion kinetics and volume expansion of the electrode during the K ion insertion/extraction process.It is a challenge to explore capable anode materials with remarkable K ion storage ability.Herein,we design and prepare SnS2 ultrathin nanosheets via a facile hydrothermal process.When severing as anode materials for K ion batteries with optimized electrolyte,SnS2 presents an improved capacity and rate ability.The capable electrochemical performance is ascribed to the reduced ion diffusion pathway and capacitor-dominated K-ion storage process.In addition,the K ion storage mechanism of SnS2 is investigated by the ex-situ X-ray diffraction technique.     

AlN-Fe纳米复合薄膜:一种新型锂离子电池负极材料

采用脉冲激光沉积技术(PLD)制备了不同比例的Al N-Fe纳米复合薄膜(Al N和Fe摩尔比为3:1;2:1;1:1;1:2),首次研究了其作为锂离子电池负极材料的电化学行为。发现当Al N和Fe的比例为2:1时,复合薄膜具有最佳的电化学性能。在500 m A·g~(-1)电流密度下,Al N-Fe(2:1)经过100次循环充放电后容量仍能保持510 m Ah·g~(-1)。对其电化学反应机理研究发现,在放电过程中,Al N-Fe纳米复合薄膜中的Al N发生分解,Al N-Fe生成Li Al合金和Li_3N。纳米Fe颗粒的引入有效提高Al N的电化学活性;在充电过程中,部分Li_3N与Fe纳米颗粒反应生成了Fe_3N,其余部分Li_3N重新生成Al N。随后的充放电过程由Fe_3N、Al N和Al三者与Li的可逆反应共同参与,保证了Al N-Fe纳米复合薄膜优异的电化学性能。该研究为设计开发新型锂离子电池电极材料提供了一种新的思路。     

A Low-Cost and Scalable Carbon Coated SiO-Based Anode Material for Lithium-Ion Batteries

Silicon monoxide (SiO) is considered as one of the most promising alternative anode materials thanks to its high theoretical capacity, satisfying operating voltage and low cost. However, huge volume change, poor electrical conductivity, and poor cycle performance of SiO dramatically hindered its commercial application. In this work, we report an affordable and simple way for manufacturing carbon-coated SiO−C composites with good electrochemical performance on kilogram scales. Industrial grade SiO was modified by carbon coating using cheap and environment friendly polyvinyl pyrrolidone (PVP) as carbon source. High-resolution transmission electron microscopy (HRTEM) and Raman spectra results show that there is an amorphous carbon coating layer with a thickness of about 40 nm on the surface of SiO. The synthesized SiO−C-650 composite shows great electrochemical performance with a high capacity of 1491 mAh.g⁻¹ at 0.1 C rate and outstanding capacity retention of 67.2 % after 100 cycles. The material also displays an excellent performance with a capacity of 1100 mAh.g⁻¹ at 0.5 C rate. Electrochemical impedance spectroscopy (EIS) results also prove that the carbon coating layer can effectively improve the conductivity of the composite and thus enhance the cycling stability of SiO electrode.