锂掺杂对石墨电化学性能的影响

研究了掺杂锂元素对用作锂离子电池负极的石墨材料的结构与性能的影响. XRD及元素分析结果表明 锂以化合物的形式存在于石墨材料中, 由于缺陷结构的增加, 掺杂后石墨材料的BET比表面积略有增大. 电化学测试结果表明 预先掺锂能够有效减少首次充放电过程中的不可逆容量, 使石墨电极的可逆容量增加. 与未掺杂的热处理石墨比较, 可逆嵌锂容量由304.5 mA*h/g增加到312.2 mA*h/g, 首次充放电不可逆容量由66.4 mA*h/g减少到52.9 mA*h/g. 以掺锂改性石墨为负极制作成063448型锂离子电池后, 电池的容量和循环稳定性均得到改善, 以1C倍率充放电时, 放电容量可达845 mA*h, 循环200次后的容量保持率为91.65%.     

碳化钙骨架碳负极材料的制备及电化学性能

以碳化钙为原料、新鲜氯气为刻蚀剂,在400～700℃范围内制备碳化钙骨架碳作为锂离子电池新型负极材料.用X射线衍射(XRD)、扫描电镜(SEM)、氮气吸附实验、恒流充放电、交流阻抗(EIS)等对碳化钙骨架负极材料进行表征及电化学性能测试,并探讨制备温度对碳化钙骨架碳结构和电化学性能的影响.结果表明:所有温度下制备的碳化钙骨架碳均为无定形碳材料,但随着制备温度的升高,材料出现部分石墨化倾向;600℃制备的碳化钙骨架碳具有良好的电化学性能,在0.1 C充放电时,首次放电比容量为890.9 mA·h/g,可逆容量为335.4mA·h/g,循环30次后的可逆容量为266.8 mA·h/g.     

锂离子电池用高容量硅/碳复合负极材料（英文）

通过镁和氧化亚硅之间的氧化还原反应制备细硅,并采用湿法混料及高温热解法合成了锂离子电池用硅/石墨/裂解碳复合负极材料。利用XRD、SEM、电化学测试考察了复合材料的结构与电化学性能,并结合循环伏安和电化学阻抗技术研究了复合材料的电化学可逆性和动力学性能。结果表明:制备的复合材料首次可逆容量为880 mAh/g,循环40次后为780 mAh/g,容量保持率可达88.6%,该方法显著改善了硅基材料作为锂离子电池负极材料的电化学性能。性能的提高主要归因于纳米结构的硅均匀分散在碳基体中,很好地抑制了充放电过程中的体积效应,同时石墨和裂解碳也充分保证了复合材料良好的导电性。     

High Reversible Capacity Si/C Composite Anodes for Lithium-Ion Rechargeable Batteries

通过镁和氧化亚硅之间的氧化还原反应制备细硅,并采用湿法混料及高温热解法合成了锂离子电池用硅/石墨/裂解碳复合负极材料。利用XRD、SEM、电化学测试考察了复合材料的结构与电化学性能,并结合循环伏安和电化学阻抗技术研究了复合材料的电化学可逆性和动力学性能。结果表明:制备的复合材料首次可逆容量为880 mAh/g,循环40次后为780 mAh/g,容量保持率可达88.6%,该方法显著改善了硅基材料作为锂离子电池负极材料的电化学性能。性能的提高主要归因于纳米结构的硅均匀分散在碳基体中,很好地抑制了充放电过程中的体积效应,同时石墨和裂解碳也充分保证了复合材料良好的导电性。     

负极材料对锂离子蓄电池性能影响试验分析

为优化锂离子蓄电池性能,分析蓄电池内负极材料对电池性能的影响,设计负极材料对锂离子蓄电池性能影响的试验。负极材料以石墨为例,制备锂离子蓄电池,并通过试验分析负极材料的预处理、粒径、用量对于锂离子蓄电池性能的影响。对一部分石墨负极材料烘烤,验证负极材料烘烤处理对锂离子蓄电池性能影响;设置8、10、15、20、2和30μm 6种粒径的石墨,试验分析负极材料不同粒径对锂离子蓄电池性能的影响;选择70%、80%、90%3种石墨负极材料用量,试验分析负极材料何种用量能够提升电池性能。试验结果显示：石墨负极材料的烘烤预处理,并不会影响锂离子蓄电池的容量保持率与电压降等性能,所以无需烘烤预处理石墨负极;石墨负极注浆为20～25μm粒径时,锂离子蓄电池放电容量最稳定,性能最佳;石墨负极用量为90%时,锂离子蓄电池恒流充放电性能、倍率性能、循环性能均最佳,锂离子蓄电池内阻最低,具有最优锂离子蓄电池性能。     

锂离子电池碳负极材料的研究现状与发展

 综述了近几年碳质锂离子电池负极材料的研究进展,比较了各类碳质材料如石墨、中间相炭微球、高比容量炭化物、石油焦、纳米碳质材料等的优缺点.重点介绍一维纳米碳质材料在锂离子电池负极材料中的应用.     

锂离子电池负极材料Li_4Ti_5O_(12)的制备及电化学性能

采用嵌段聚合物型表面活性剂P123作为结构导向剂,利用溶胶-凝胶方法制备出纳米TiO2作为合成Li4Ti5O12锂离子电池负极材料的原料之一.然后采用湿法球磨辅助的固相反应合成方法,以丙酮作为球磨介质,制备出Li4Ti5O12锂离子电池负极材科,并对所制备的Li4Ti5O12电极材料进行扫描电镜SEM、透射电镜TEM、粉末X射线衍射(XRD)、循环伏安(CV)以及循环性能测试.电化学性能测试表明所制各出的锂离子电池负极材料Li4Ti5O12具有较高的放电比容量和优异的循环性能.在电流密度为16 mA/g时首次放电比容量为155 mAh/g,首次库仑效率为98.3%.300次循环结束时放电比容量仍可达150.8 mAh/g,约为首次放电比容量的97.3%,300次循环容量仅衰减了2.7%.     

石墨表面金属化处理及检测

石墨是一种较为理想的锂离子电池负极材料,但由于其与溶剂的相容性差等缺点,降低了电池的容量和寿命,研究发现,通过对石墨材料进行修饰与改性可有效提高石墨电极性能.介绍了在石墨表面进行金属化处理的方法以及处理后对石墨电化学性能的影响,并概括介绍了所包覆金属的检测方法,结果表明,石墨表面包覆一层金属后,不仅电阻率大大降低,且改善了电极在充放电过程中石墨体积的变化,降低了电极膨胀,电极热稳定性和循环性均得到了提高.     

均匀沉淀法制备SnO2-石墨复合粉及其电化学性能

以SnCl4为原料,尿素为沉淀剂,采用均匀沉淀法制备了SnO2-石墨复合粉,用XRD、SEM、TG-DTA以及电化学方法对复合粉进行了表征.结果表明:由于SnO2和石墨表面上不可避免的电化学还原,导致复合粉的首次循环具有较大的不可逆容量,经600℃煅烧4 h的复合粉具有较高的可逆容量和循环性能;含30%SnO2的复合粉在0.1 C的电流倍率下进行充放电,其初始容量达到520.0 mA·h/g,经30次循环后平均每次循环的容量衰减率为0.6%,表明SnO2-石墨复合粉是一种具有发展前途的锂离子电池负极材料.     

Li4Ti5O12/石墨复合材料的湿法制备与表征

以醋酸锂、钛酸丁酯和石墨为原料,无水乙醇为溶剂,采用湿法制备Li4Ti5O12/石墨复合材料.采用X射线衍射、红外光谱、扫描电镜和电化学测试对合成产物进行表征.结果表明:600 ℃氩气气氛中煅烧6 h可制得含碳量5%左右的Li4Ti5O12/石墨复合材料,其可逆容量达到167.1 mA·h/g;经80次循环后,0.1C放电时容量保持率为99.0%,2.0C放电时容量保持率达到105.1%.与纯Li4Ti5O12相比,Li4Ti5O12/石墨复合材料具有更好的循环性能和倍率性能,是一种优良的锂离子电池负极材料.     

Effects of modification on performance of natural graphite coated by SiO2 for anode of lithium ion batteries

A stable silicon dioxide film was coated on the surface of natural graphite anode by sol-gel method with Si（OCH2CH3）4, and effects of modification on performance of natural graphite were investigated. The structure and properties of graphite samples were determined by X-ray diffi＇actometry（XRD）, scanning electron microscopy（SEM）, energy-dispersive X-ray spectroscopy（EDS） and electrochemical measurements. The modified graphite shows mainly the layer structure, and silicon dioxide film is amorphous. Compared with the pure natural graphite, the modified graphite exhibits the higher specific capacity of 366 mA-h/g. After 40 charge-discharge cycles, the capacity retention ratio of the modified graphite reaches 99.55%, while that of natural graphite is only 83.04%. The results indicate that the surface modification of natural graphite by SiO2 is effective for improving the electrochemical performance of the natural graphite anode for lithium ion batteries.     

Effect of lithium or aluminum substitution on the characteristics of graphite for anode of lithium ion batteries

Modification of graphite for anode of lithium ion batteries is investigated. Results of X-ray diffraction shows lithium and aluminum exists as Li compound (CH3COOLi-2H2O) and Al compound (AID3) in the graphite, respectiovely. The Brunauer-Emmer-Teller (BET) surface area of the modified graphite increases. According to the electrochemical measurements of Li/C cell and prototype Li-ion batteries, the Li-doped graphite has large reversible capacity of 312.2 mA·h/g, low irreversible capacity of 52.9 mA·h/g, and high initial coulombic efficiency of 85.51 %. The 063448 size proto-type battery with Li-doped graphite anode has large discharge capacity of 845 mA·h and good cycling performance. The initial charge/discharge characteristic of Al-doped graphite is close to those of undoped graphite, but the prototype battery with Al-doped anode shows the best cycling performance with capacity retention ratio of 94.06% at the 200th cycle.     

Ag+-掺杂锂钒氧化物的合成及其电化学性能

报道了用V2O5湿凝胶、Li2CO3和Ag2CO3通过液相反应合成用于锂离子电池正极材料的Ag -LiV3O8.其前驱体和产品分别利用热分析(DTA-TG)、扫描电镜(SEM)、X射线衍射(XRD)、红外光谱(IR)技术进行表征.其电化学性能通过恒电流充放电、循环伏安法和交流阻抗技术进行研究.实验表明,活性材料在不同的放电倍率和1.8～3.6 V的电压范围内具有较高的首次放电容量;在0.15 C循环250次后保持180 mAh/g的放电容量.     

Optimization of iron sulfides usage in electrolytic composites with graphites for lithium-ion batteries

Iron sulfides were codeposited with different nature graphite for the increase of the utilization efficacy in their electrochemical reaction with lithium. Synthesized iron sulfide-graphite composites have been investigated in the galvanostatic mode using a model lithium accumulator filled with an electrolyte solution of 1 M LiClO₄ in EC, DMC. It was established that the codeposition of iron sulfides with synthetic graphite stabilizes the discharge capacity of electrolytic iron sulfides at their long cycling. Synthesized iron sulfide composites with synthetic graphite represent prospective negative electrodes for thin-layer lithium-ion batteries. The natural graphite manufactured by the Superior Graphite Company (purified surface coated natural graphite, ABG 1005, ABG 1010, formula BT SLC 1520 P) displays an unfit stabilization ability of the iron sulfide discharge capacity.     

Improving the electrochemical performance of LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript>/graphite batteries using LiF additive during fabrication

LiMn2O4/graphite batteries using LiF additive were fabricated and their electrochemical performance including discharge,cycling and storage performances were tested and compared with LiF-free LiMn2O4/graphite batteries.The LiMn2O4/graphite battery with LiF added shows better capacity (107.5 mAh/g),cycling performance (capacity retention ratio of 93% after 100 cycles),and capacity recovery ratio (98.1%) than the LiF-free battery.The improvement in electrochemical performance of the LiF-added LiMn2O4/graphite...     

锂离子电池用石墨负极材料改性研究进展

石墨是目前商业化锂离子电池应用最广的负极材料,日益增长的市场需求对石墨负极材料的储锂性能提出了更高的要求。概述了锂离子电池的工作原理和石墨嵌锂机制,针对石墨负极材料理论比容量(372 mA.h/g)较低和电解液兼容性较差等问题,总结了近年来石墨负极材料的改性手段,主要分为表面改性和结构调控等2类,其中表面改性技术包括氧化和卤化处理,特点是通过调控界面化学性质,可增强石墨结构的稳定性,促进稳定SEI膜的形成,但对于石墨储锂容量的提升非常有限;结构调控包括剥层法和缺陷构筑法,特点是通过扩大石墨层间距、降低石墨维度及在石墨结构上构筑缺陷,从而增加锂离子的活性位点,提供更多锂离子扩散通道,缓解循环过程中的体积变化,改善石墨与电解液的相容性,显著提升石墨的储锂性能。最后对石墨负极材料的未来发展趋势进行了展望。     

Structure and electrochemical performance of spinel LiMn2O4 synthesized by mechanochemical process

1　INTRODUCTIONLithium ion battery was used in many areasbecause of its high voltage, high energy densityand long cycle life and so on. Spinel lithium man ganese oxide was one of the most promising mate rials in term of its environmental benign, low cost,easy preparation and temperature safety. Mainproblem is the poor cycle life. As we all know thatboth the structure and electrochemical performanceof material strongly depended on the preparingmethod and starting…     

Electrochemical properties of some cobalt antimonides as anode materi-als for lithium- ion batteries

Some cobalt antimonides have been prepared and studied as the candidate anode materials for lithium ion batter-ies. Reversible capacities of 424,423 and 546 mA·h·g-1 were measured at the first cycle for as-solidified CoSb2, CoSb3 and annealed CoSb3 respectively. A low lithium ions diffusion coefficient in the order of 10-16 m2·s-1 was estimated from the coulometric titration measurements in the annealed CoSb3 electrode. It was found that the electrochemical properties of fine powders are significantly better than coarse powders. However the SEM picture shows that the nano-sized CoSb3 powders gathered to larger granules, which worsens somewhat the capacity retention of the nano-sized materials, although the volume capacities of the annealed and ball milled CoSb3 remain near twice of that of graphite after 50 cycles.     

Hydrothermal Preparation of Homogeneous Cobalt Oxide Nanomaterials as Stable Anodes for Superior Lithium Ion Batteries

In this study,uniform Co_3O_4 nanoparticles are prepared via a simple and facile hydrothermal synthesis without calcination treatment.When the Co_3O_4 nanomaterials are investigated as anodes for lithium ion batteries,a good electrochemical property is achieved.Particularly,the reversible capacity of the as-synthesized Co_3O_4 nanoparticle has a significant growth from383 mAh g~(-1) of the initial cycle to 471 mAh g~(-1) of the 300 th cycle at 2 A g~(-1).Moreover,when it recovers to 50 mA g~(-1) after different current densities,a superior reversible capacity of 695 mAh g~(-1) can be reached.Such favorable electrochemical properties will make the as-obtained Co_3O_4 have a good application prospect as anode material for lithium ion batteries.