锂离子电池负极用碳/硅复合材料的研究进展

硅(Si)因具有资源丰富、理论容量高、绿色环保等优点成为世界上最具有前景的锂离子电池负极材料之一。但硅的导电性能差,且在合金化/去合金化过程中会发生剧烈的体积膨胀导致电池循环稳定性严重下降。碳材料(C)导电性能优异且结构稳定。将C和Si进行复合,可得到容量高且循环性能好的锂离子电池负极材料。本综述从材料的制备方法着手,总结了锂离子电池C/Si复合负极材料的最新研究进展,探讨了制备方法、材料结构对C/Si复合负极材料储锂性能的影响。     

锂离子电池锡基负极材料的研究进展

锡基负极材料与碳负极材料相比,具有容量密度高,安全性好等优点,成为动力锂离子电池用新型负极材料研究的热点之一。本文综述了近年来国内外针对锡基材料首次不可逆容量高、循环性能差等问题所进行的改性研究,分别从材料的制备方法、组成结构及电化学性能等方面进行比较分析,并对锡基负极材料的进一步研究、发展应用予以展望。     

CNT@SnO_2@C纳米复合物的制备及其储锂性能

为改善锂离子电池负极循环性能,提高其安全性和稳定性,制备了氧化锡-碳锂离子电池负极材料。以有机聚合物碳纳米管(PNT)为前驱物骨架、沸石咪唑骨架材料-8(ZIF-8)为碳基修饰材料、纳米片状氧化锡为主体材料,合成出一种CNT@SnO_2@C纳米复合物,该材料的比表面积为125. 6 m~2/g。在作为锂离子电池负极材料应用时,2 A/g电流密度下循环600次,容量依然可以保持在878 mAh/g,具备优异的高比容量和持久的循环性能。     

石墨化无烟煤基锂离子电池负极材料研究

以宁夏石嘴山太西无烟煤为原料,经过粗碎、磨粉和石墨化等简单工艺制备了无烟煤基锂离子电池负极材料。测试结果表明,石墨化无烟煤基负极具有92.23%的石墨化度,表现出340.2 mA·h/g的可逆容量,与煅前石油焦基石墨负极容量相当。与针状焦基石墨负极相比较,无烟煤基石墨负极虽然克容量较低,但在电池的循环稳定性方面具有较大优势。     

高容量锂离子电池硅基负极材料的研究现状与发展北大核心

硅基材料因具有高比容量的特点成为新一代高容量锂离子电池的负极材料,但其在锂离子脱嵌锂过程中存在严重的体积效应,降低了电池的循环稳定性和初始库伦效率,从而限制了其商业化应用。本文综述了近几年来锂离子电池硅基负极材料的主要改性方法和研究进展,阐述了硅基材料作为锂离子电池负极材料存在的问题,并指出其未来的发展方向。     

高容量锂离子电池硅基负极材料的研究现状与发展

硅基材料因具有高比容量的特点成为新一代高容量锂离子电池的负极材料,但其在锂离子脱嵌锂过程中存在严重的体积效应,降低了电池的循环稳定性和初始库伦效率,从而限制了其商业化应用。本文综述了近几年来锂离子电池硅基负极材料的主要改性方法和研究进展,阐述了硅基材料作为锂离子电池负极材料存在的问题,并指出其未来的发展方向。     

磷掺杂葵花盘基活性炭在锂离子电池负极材料中的应用

通过简单水热和活化方法制备磷掺杂葵花盘基活性炭,采用SEM,TEM,BET,Raman,XRD等方法对材料进行表征,将其用作锂离子电池负极材料。结果表明,活性炭材料用作锂离子电池负极材料时比容量高,库伦效率好,循环性能稳定。在500 mA/g的电流密度下,首圈充电容量达1052 mAh/g,库伦效率为48.9%。经200次循环后,容量仍保持在1000 mAh/g以上。     

锂离子电池用硅基复合材料的研究进展

锂离子电池硅负极材料具有很高的理论比容量(4200 m Ah/g),但其在充放电过程中巨大的体积变化导致循环性能很差,同时较低的电导率也限制了硅在锂离子电池中的应用前景。将硅与其它材料进行复合是改善硅基负极材料循环稳定性、提高其倍率性能的主要途径。文章综述了近年来硅基复合材料的研究进展,以期为硅基复合材料的研究提供参考。     

二硫化钼/碳纳米片复合材料的制备及其锂离子电池性能研究

二硫化钼由于具有高的理论比容量和大的层间距,作为锂离子电池的负极材料引起了研究人员的广泛关注。由于其在循环过程中结构的塌陷与体积膨胀,导致容量快速衰减。本文通过模板法制备出多孔碳纳米片,进而采用水热法在其表面合成均匀的二硫化钼纳米片。通过SEM,TEM,XRD,BET等对合成的材料的微观形貌和结构进行表征。相互交织多孔碳纳米片网络能够有效缩短锂离子传输距离,提高二硫化钼的导电性,从而提升复合材料的电化学性能。将其用作锂离子电池负极材料,在100m Ag~(-1)的电流密度下,呈现出815m Ahg~(-1)的比容量,展现出良好的循环稳定性能,经过50次循环后容量保留可达96.5%,并且具有较好的倍率性能。     

铋基材料作为锂离子电池负极材料的研究进展

铋基材料因其高体积容量、电压平台较低等优点而被用作锂离子电池负极材料。本文总结了近几年铋基材料用作锂离子电池负极材料的研究进展。     

高硫石油焦基活性炭的制备及其在二次电池负极材料中的应用

以我国产量较大的山东淄博高硫石油焦为原料,利用KOH活化法,于800℃下通过改变碱焦质量比(质量比为1∶1,2∶1,3∶1,4∶1)制备得到不同比表面积的高硫石油焦基活性炭(AC-PC-X),利用比表面积分析仪对其孔结构进行了分析,并进一步利用水热法担载Mn₃O₄制备得到AC-PC-X/Mn₃O₄复合材料,分别将AC-PC-X/Mn₃O₄和高硫石油焦基活性炭作为二次电池负极材料分别应用于锂离子电池和钾离子电池中,利用JSM-7001F型热场发射扫描电子显微镜和JEM-2100F型场发射透射电子显微镜观察了负极材料的微观形貌,以及利用LAND CT2001A型电池测试系统和CHI660D型电化学工作站考察了负极材料的性能。结果表明:不同碱焦质量比条件下制备得到的高硫石油焦基活性炭均以微孔结构为主,比表面积随碱焦质量比的增加而增大;碱焦质量比为3∶1时制备得到的高硫石油焦基活性炭(AC-PC-3,比表面积为996m²/g)表现出最佳的长期循环稳定性,比表面积过大或过小的高硫石油焦基活性炭的电化学稳定性均不如ACPC-3的电化学稳定性。在锂离子电池中,AC-PC-3/Mn₃O₄在初始循环中的比容量为907mAh/g,但其循环容量衰减较慢,120次充/放电循环后其稳定比容量为400mAh/g;在钾离子电池中,ACPC-3在500次循环后比容量几乎没有衰减,稳定在95mAh/g。     

Solvothermal synthesis of nanosized CoSb2 alloy anode for Li-ion batteries

The nanocrystalline CoSb₂ was prepared by a solvothermal method at various temperatures and was investigated as a potential anode material for lithium-ion batteries. It was found that the CoSb₂ is highly crystallized at 190 °C and with almost a single-phase structure. The morphology of the alloy powder plays an important role in their cycling behavior. The large reversible capacity and better capacity retention of these nanosized CoSb₂ alloys make them promising anode materials for Li-ion batteries.     

钒酸镍锂离子电池负极材料的研究进展

综述了近年来国内外关于钒酸镍材料的合成方法、结构性质以及应用于锂离子电池新型负极材料的研究进展。钒酸镍(Ni3V2O8、NiV3O8等)电极材料具有成本低、环境友好、比容量高、倍率性能优异等优点,但其在充放电过程中体积的巨大变化、电导性差以及比表面积低等问题严重影响了其规模化应用。该文从三个方面阐述了近年来通过电极材料微纳米化、复合化、表面包覆等手段有针对性的进行钒酸镍电极材料改性的研究进展,积极探索了高性能钒酸镍材料的合成方法,展望了今后重点开展的研究方向,对于钒酸镍材料的广泛应用具有一定的学术价值和实用意义。     

Nanometer copper-tin alloy anode material for lithium-ion batteries

Nanometer copper-tin alloy anode materials with amorphous structure were prepared by a reverse microemulsion technique for lithium-ion batteries. It was found that the electrochemical performance of alloy was influenced by its particle size, which was controlled by appropriate surfactant content. The nanometer copper-tin alloy with particle size of 50-60 nm presented the best performance, showing a reversible specific capacity of 300 mA h/g over the full voltage range 0.0-1.2 V and capacity retention of 93.3% at 50 cycles. A great irreversible capacity was caused by the formation of a SEI layer on the surface of nanometer alloy. The contact resistance between nanometer particles resulted in the poor electric conductivity and the match of particle size and conductive agent content had a great impact on the electrochemical performance of the nanometer copper-tin alloy anode.     

Effect of particle shape on the electrochemical properties of CaSnO3 as an anode material for lithium-ion batteries

Cubic and star-shaped CaSnO₃ particles with a perovskite structure were synthesized successfully using a simple hydrothermal method at a low temperature of 140 °C. The structure and morphology of the CaSnO₃ powders were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The electrochemical properties of the CaSnO₃ as anode materials for lithium-ion batteries were tested by constant current discharge/charge and cyclic voltammetry. The large irreversible capacity in the initial cycle was similar to that of tin oxide, due to the decomposition of tin oxide into metallic tin and Li₂O, followed by a reversible Li–Sn formation. The reversible capacity of the cubic CaSnO₃ was 382 mAh g^?1 in the first cycle and was maintained at 365 mAh g^?1 in the following cycles. The cubic CaSnO₃ particles had a higher reversible capacity than the star-shaped CaSnO₃ particles and retained a capacity of about 365 mAh g^?1 after 60 cycles as well as good cycle stability, showing potential as attractive anode materials for lithium-ion batteries. It is found that the particle shape had a marked effect on electrochemical performance.     

Defect engineering on the defluorinated MWCNTs@SnO2@N-doped carbon composite for enhanced lithium storage performance

When tin oxide (SnO₂) is used in the anode of lithium-ion batteries, its capacity decreases dramatically due to poor conductivity and volume effects during the electrochemical cycle. Although composites with traditional carbon-based materials can improve this shortcoming, the low capacitance of such materials still limits the capacity of the composites. Therefore, we applied defect engineering to SnO₂/C composite electrodes for the first time, and prepared D-MWCNTs@SnO₂@N–C composite electrodes with hollow rod structures. Defects were constructed in the carbon materials to promote electron diffusion and ion storage active sites. The hollow structure can adapt to the volume change that occurs during Li-ion insertion/desorption. In addition, the detachment of F atoms and the insertion of N atoms, which are chemical processes that occur on the surface of carbon materials, promote an increase in surface porosity and defect density, thereby providing additional lithium storage sites. The double carbon effect caused by defect engineering provides a multidimensional transport path and rapid migration rate for Li-ions, which enables the electrode to display excellent electrochemical performance; thus, this work could lead to the preparation of next-generation anode materials with high energy storage capacity, high rate capability and high cycle stability.     

Electrochemical performance of Sn film reinforced by Cu nanowire

Sn/Cu nanowire composite film was electrodeposited on copper foil substrates and used as an anode material for lithium-ion batteries. The structure of the obtained composite film anode was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performance was evaluated by cyclic voltammetry, galvanostatic cycling and impedance spectroscopy. It was found that the Sn/Cu nanowire composite film anode showed a better cycle stability than Sn film anode, whereas the Sn/CNT composite film anode indicated poor capacity retention. It could be deduced that copper nanowire reinforced the Sn film anode due to the better wetting property of Sn on the surface of copper and reduced the loss of electric contact among tin particles in the Sn/Cu nanowire composite film anode.     

中间相炭微球在锂离子电池负极材料的应用进展

中间相炭微球(MCMB)具有良好锂离子扩散性、导电性和机械稳定性等优势,是目前应用广泛、综合性能优异的锂离子电池负极材料,但较低理论比容量是制约其发展的关键因素。为了获得性能优良的MCMB基锂离子电池负极材料,改性修饰和复合材料已然成为目前研发重点。笔者论述了碳结构、表界面和复合材料等微观结构设计对MCMB负极材料电化学性能的影响。从碳堆积结构类型、有序性、层间距以及球体粒径大小等方面,论述了碳结构微观设计对MCMB电化学性能的影响。发现具有乱层结构的MCMB在充放电过程中内部产生应力较小,且碳结构较稳定,具有优异循环稳定性;内部具有大量微孔或碳层间距较大的MCMB,在充放电过程中可提高锂离子在电极中的迁移速率,并提供更多的储锂空间,一般具有优良的充放电比容量和倍率性能;小粒径MCMB具有较短的锂离子迁移路径和随之增加的比表面积,通常具有较好倍率性能,伴随着可逆比容量和充放电效率的衰减。从表界面碳层改性、包覆和掺杂改性等方面,论述了表界面改性对MCMB电化学性能的影响。表面碳层修饰可增加MCMB与电解液的相容性及其比表面积,提高了与电解液的接触面积及贮锂容量,改善了锂离子电池负极材料的电化学性能;另外,MCMB表面包覆一层无定型碳,可避免其表面与电解液直接接触,减少电化学副反应的产生,提升其可逆比容量。从碳活性物质复合材料、非碳活性物质复合材料等方面,论述了复合材料微观结构设计对MCMB电化学性能的影响。碳活性物质可降低MCMB内部碳层结构的有序性,减少锂离子嵌入过程中的内部应力,提升MCMB循环稳定性。非碳活性物质诱导MCMB生成更加有序的碳层结构,提高MCMB的比表面积,从而改善MCMB表面与电解液分子的接触能力及其嵌锂性能,有利于提升MCMB负极材料可逆比容量、循环性能和倍率性能。MCMB具有高碳层间距和多缺陷位点等结构特征,有利于钠离子自由脱嵌,应用于钠离子电池时具有良好的可逆比容量、循环稳定性和倍率性能。MCMB的不规则定向层状结构经活化等处理具有较高比表面积,可应用于超级电容器电极材料。最后提出在高性能锂离子电池电极材料快速发展的需求下,从微观结构角度设计MCMB纳米复合材料将是MCMB负极材料的研究重点。     

锂离子电池用层状LiMnO2基正极材料的研究进展

层状LiMnO2材料因其结构不稳定、循环性能差,因而需对其进行掺杂改性.层状锰系衍生物具有比容量高、循环性能稳定等优点,已成为锂离子电池新的发展方向.介绍了目前对LiMnO2的掺杂改性研究,对多元层状锰基固溶体正极材料作了重点阐述.总结了近年来关于多元层状锰基正极材料的研究发展,介绍了其晶体结构、电化学性能、合成与制备技术,以及进一步的改性研究.如果多元层状固溶体材料的高倍率放电性能得到进一步的提高,则其必将成为新的一代锂离子电池正极的首选材料.     

花状SnSe0.5S0.5@N-C复合材料的制备及其在钠离子电池中的应用

为了设计具有高容量和循环稳定性的钠离子电池负极材料,合成了有序花状SnSe,在其表面进行氮碳掺杂,并进一步硫化,得到有序花状SnSe0.5S0.5@N-C复合材料.采用SEM、TEM、XRD、XPS对复合材料的结构和形貌进行了表征,并将其作为钠离子电池负极进行了性能测试.结果表明,当SnSe0.5S0.5@N-C作为钠离子电池负极时,表现出较高的可逆容量和优异的循环性能.在0.2 A/g电流密度下,复合材料在循环100圈后的可逆比容量仍可高达430.7 mA·h/g.