LiMn2O4的Al2O3室温固相包覆及其电化学性能研究

首次采用一种室温固相法对LiMn2O4进行Al2O3表面包覆。采用X射线衍射（XRD）,扫描电镜（SEM）技术对产物的结构和形貌进行了表征,同时对其电化学性能进行了检测。结果表明,通过表面包覆,LiMn204材料的循环性能,特别是高温循环性能,得到了有效的改善。在3．25～4．35V的充放电电压区间内,表面包覆AlE0,质量分数为1％所制备的LiMn2O4材料显示出优良的电化学性能,在25℃和55℃,分别可达到0．5C 120．2mAh／g和117．9mAh／g,经过50次循环后容量保持率分别为96．59％和94．23％。     

锂离子动力电池正极材料的研究进展

介绍了锂离子电池正极材料钴酸锂、镍酸锂、磷酸铁锂和锰酸锂的性能,以及它们作为动力电池正极材料的可行性。磷酸铁锂和锰酸锂以其优异的性能成为最热的动力电池正极材料,并且锰酸锂的研究及应用进展表明锰酸锂已经成为锂离子动力电池正极材料的首选。     

锂离子电池正极材料Li_(1+x)V_3O_8的研究进展

介绍了锂离子电池正极材料Li1 x V3O8的组成、结构和性能,简单介绍了其制备方法,指出了Li1 xV3O8材料的一些缺点及今后应进一步开发研究的方向.     

固相烧结辅助高温球磨合成LiNi_xMn_(2-x)O_4

以氢氧化锂、硝酸镍、二氧化锰为原料,用固相烧结辅助高温球磨方法,合成了具有Ni掺杂的LiMn_2O_4正极材料。研究了Ni在不同掺杂量时对材料的相结构、形貌和充放电性能的影响,并与未掺杂Ni的LiMn_2O_4进行对比。结果表明,掺Ni后材料的放电比容量随着掺杂量的增大逐渐减小,而材料的容量保持率相比未掺杂时略有提高;当掺杂量x=0.05时,所得产物的充放电性能最佳,首次放电容量达到122.9mAh/g,充放电容量保持率在40次循环后为97.48%。     

尖晶石型锰酸锂性能改善方法

尖晶石型锰酸锂是非常有发展前景的锂电正极材料,叙述了改善尖晶石型锰酸锂电化学性能及加工性能的方法,包括优化其粒度分布、降低杂质含量、控制一次晶粒及整体颗粒形貌、元素掺杂、表面改性以及制备方法优化等。     

锂离子电池正极材料的研究现状

在简要介绍新一代充电电池——锂离子电池近年发展概况的基础上，阐述了锂离子电池几种正极材料（LiCoO2、LiNiO2、LiMn2O4、LiFePO4及锂钒氧化物等）的研究现状。     

锂离子电池正极材料Li0．99Re0．01FePO4的合成及性能

采用固相反应法合成了锂离子电池正极材料Li0．99Re0．01FePO4（Re=Er、Y、Gd、Nd、La）。采用X射线衍射、恒电流充放试验对试样的微观结构和电化学性能进行测试。试验结果表明：掺杂稀土金属离子对LiFePO4的晶体结构没有影响。试样Li0．99Gd0．01FePO4的电化学性能最佧,在C／10和1C倍率下放电容量均最大,分别为136．63mAh／g、121．74mAh／g。     

Influence of Doping Rare Earth on Performance of Lithium Manganese Oxide Spinels as Cathode Materials for Lithium-Ion Batteries

The cathode material plays an important role inthe performance of lithium ion batteries. Commerciallithium cells use lithium cobalt oxide cathodes and thehigh cost of this material has prompted the design andsynthesis of alternate insertion hosts. Among these al ternatives, spinel LiMn2O4 has been found to bepromising in terms of specific energy, non toxicity,and low cost[1~3]. It is thought that lithium man ganese oxides will be used in lithium ion batteries forel…     

Preparation and electrochemical properties of Y-doped Li3V2（PO4）3 cathode materials for lithium batteries

Y-doped Li3V2(PO4)3 cathode materials were prepared by a carbothermal reduction(CTR) process. The properties of the Y-doped Li3V2(PO4)3 were investigated by X-ray diffraction (XRD) and electrochemical measurements. XRD studies showed that the Y-doped Li3V2(PO4)3 had the same monoclinic structure as the undoped Li3V2(PO4)3. The Y-doped Li3V2(PO4)3 samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram (CV), and electrochemical impedance spectra (EIS). The optimal doping content of Y was x=0.03 in Li3V2-xYx(PO4)3 system. The Y-doped Li3V2(PO4)3 samples showed a better cyclic ability. The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through the Y-doping. The improved electrochemical performances of the Y-doped Li3V2(PO4)3 cathode materials were attributed to the addition of Y3+ ion by stabilizing the monoclinic structure.     

尖晶石LiMn2O4正极材料的掺杂改性研究

掺杂是目前改善LiMn2O4正极材料性能的主要途径.结合容量衰减原理,综述并分析了掺杂各种阳离子、阴离子及复合掺杂分别对材料各项性能的影响,提出了阴阳离子的复合掺杂是改善材料综合性能的有效方法.     

碳热还原法制备LiFePO4/C锂电池正极材料的研究

以Fe2O3为铁源,NH4H2PO4为磷源,Li2CO3为锂源,蔗糖为碳添加剂,应用碳热还原一步烧结法制备了LiFePO4/C复合粉体材料,系统的研究了烧结温度、烧结时间和锂铁比对样品电化学性能的影响。研究结果表明,对电化学性能影响因素最大的是烧结温度、其次是锂铁比,最后是烧结时间。当烧结温度为700℃、锂铁比为1.00、烧结时间为12 h时样品所得的电化学性能最佳,它在0.1C,0.5C和1.0C倍率下的首次放电比容量分别为130.1,118.2和105.6 mAh.g-1,经20次循环后,不同倍率下样品的容量的保持率分别为99.8%,98.9%和97.5%。     

喷雾干燥法合成锂离子电池复合正极材料xLiFePO4.yLi3V2(PO4)3及性能研究

采用喷雾干燥和高温固相法合成了一系列xLiFePO4·yLi3 V2( PO4)3复合正极材料.电化学测试结果表明,0.95LiFePO4·0.05Li3 V2( PO4)3复合正极材料具有较高的比容量、优良的循环性能和倍率性能,在电压范围为2.0V～4.3V,0.1C,1C,5C条件下的放电容量分别为162.7,147.7和122.3 mAh·g-1.0.5LiFePO4·0.5Li3 V2(PO4)3和0.3LiFePO4·0.7Li3 V2 (PO4)3复合正极材料则表现出了良好的倍率性能,5C,10C充放电条件下容量保持率分别为:77％,73％,88％,82％.     

Co掺杂对锂离子电池材料LiMn2O4性能的影响

采用高温固相法和溶胶-凝胶法制备LiCoXMn2-XO4（x=0,0.05,0.1,0.2）,研究了掺杂Co后,材料的相结构和充放电性能,并与LiMn2O4相对比.结果表明：掺杂Co后材料的充放电性能相对LiMn2O4均有所提高;两种方法制备的LiCoXMn2-XO4循环40次后,容量保持率、放电比容量均优于LiMn2O4;且当x=0.05时,两种方法制备的LiCoXMn2-XO4的充放电性能均明显优于x=0.1和x=0.2时.     

不同形貌锰酸锂材料的合成及性能研究

介绍了3种不同形貌（不规则团聚态、球形和单晶态）的锰酸锂的制备方法,并研究了他们的性能.将3种样品分别制成扣式电池、聚合物电池,研究材料形貌与电化学性能关系,同时采用XRD、DTA等测试方法,研究材料形貌对材料结构和热稳定性的影响.研究发现不规则团聚态锰酸锂各项性能指标最差;球形锰酸锂倍率放电能力最好,其他性能居中;单晶态锰酸锂压实密度最高,循环性能和热稳定性最好.     

Influences of Nd~（3＋） doping on structure and electrochemical performance of layered Li_（1.05）V_3O_8

Nd3+-doped Li1.05V3O8 was synthesized by liquid-state reactions combined calcination.The influences of Nd3+ doping on physical and electrochemical performances of Li1.05V3O8 were investigated using X-ray diffraction (XRD),cyclic voltammograms,a.c.impedance and galvanostatic charge-discharge tests,etc.Results indicated that Nd3+-doped products had well developed crystal structure of layered LiV3O8 and uniform particle size distribution.Nd3+ doping with a proper amount improved the initial discharge capacity,discharge voltage and ion conductivity of the cathode material to some extent.Nd3+ did not participate in the electrochemical reactions and was beneficial to stability of the crystal structure during cycling.     

具有核壳结构的高电压正极材料Li(Co_(0.9)Ni_(0.05)Mn_(0.05))O_2的制备与表征

以共沉淀法制备的Ni-Mn包覆Co_3O_4前驱体和Li_2CO_3为原料,通过高温固相法制得了具有核壳结构的锂电池正极材料Li(Co_(0.9)Ni_(0.05)Mn_(0.05))O_2.用扫描电镜(SEM)、X射线能谱仪(EDS)、X射线衍射(XRD)和充放电测试表征了样品的形貌、晶体结构和电化学性能.结果表明,所制备的核壳结构Li(Co_(0.9)Ni_(0.05)Mn_(0.05))O_2具有良好的电化学性能,在3.0~4.5 V和3.0~4.6 V,0.2 C下首次放电容量分别达到180.5 m A·h·g~(-1)和201.3 m A·h·g~(-1),在1 C下,循环50周后容量保持率分别为89.3%和63.3%.     

掺杂稀土元素对锂离子电池正极材料LiMn2O4的影响

尖晶石LiMn2O4作为锂离子电池最有潜力的正极材料已经成为研究的热点，但其在充放电过程中结构的不稳定制约了其应用。近年来，许多研究学者对LiMn2O4进行稀土掺杂，有效地提高了LiMn2O4材料的电化学性能和循环稳定性。文章综述了近几年在这方面的研究进展。     

Influence of Sc3+ on LiMn2O4 cathode materials at elevated temperature

Sc3 -doped lithium manganese oxides were synthesized by solid-state reaction. The influences of doping element on structure,mean valence of manganese, and electrochemical performances were studied by X-ray diffraction (XRD), galvanostatic charge-discharge and cyclic voltammetric tests, and also electrochemical impedance spectroscopy (EIS). XRD tests showed that doped lithium manganese oxides were pure spinel structure without other phases. Redox titration and visible spectrophotometry tests indicated that the mean valence of man-ganese in doped lithium manganese oxides was higher than that of pure one. LiSc0.02Mn1.98O4 remained 92.9% of the initial specific discharge capacity after 50th cycle at a constant current of 50 m/g, and the reversibility of LiSc0.02Mn1.98O4 was improved in comparison with pure LiMn2O4 at 50 ℃. EIS indicated that film deposition on spinel particles was suppressed because of Sc3 doping, and the charge transfer be-tween the surface film and spinel particles with increasing temperature for Sc3 -doped materials became easier as compared with undoped one.     

高温球磨烧结合成LiCoxMn2-xO4

采用液相法合成前驱体，并通过高温球磨烧结法合成了LiCoxMn2-xO4正极材料。考察Co掺杂量对材料的相结构、形貌、电化学性能的影响。结果表明，Co掺杂后材料的首次放电比容量随着Co掺杂量的增大逐渐减小，而循环性能较好。其中LiCo0.05Mn1.95O4的首次放电比容量达到119.0 mAh/g，在不同倍率下循环100次后的容量保持率为92.52%，表现出很好的电化学可逆性和循环稳定性。     

超声辅助TiO2包覆尖晶石LiMn2O4及电化学性能研究

采用超声辅助溶液法在尖晶石LiMn2O4表面包覆TiO2.通过X射线衍射、扫描电子显微镜、恒电流充放电、交流阻抗技术分析合成材料的结构、形貌及电化学性能.结果表明:TiO2包覆LiMn2O4与LiMn2O4具有相似的X射线衍射结果,衍射峰尖锐,样品颗粒大小均匀,无明显团聚.室温下0.2C充放电时,表面包覆1％TiO2的LiMn2O4首次放电比容量为123.51 mAh·g-1,略低于未包覆LiMn2O4的124.02 mAh·g-1,但在2C和4C高倍率时,表面包覆1％TiO2的LiMn2O4比容量分别为105.54和80.73 mAh·g-1,远高于未包覆的79.76和66.37 mAh·g -1.室温及55℃下以0.2C倍率循环50后,表面包覆1％ TiO2的LiMn2O4容量保持率分别为91.69％和87.36％,远高于未包覆LiMn2O4的86.58％和78.02％.室温下以1C倍率循环100次后,表面包覆1％ TiO2的容量保持率比未包覆LiMn2O4高出3.75％.表面包覆TiO2后LiMn2O4的循环性能得到了大大的提高,尤其是高温循环性能.