低冰镍衍生的具有高结构稳定性和快速扩散动力学的钠离子掺杂层状LiNi1/3Co1/3Mn1/3O2正极(英文)

通过共沉淀法合成钠离子(Na⁺)掺杂的高稳定性Li_1-xNa_xNi_1/3Co_1/3Mn_1/3O₂(NCM-Na)正极材料。首先论证采用低冰镍提取镍作为合成材料镍源的可行性。其次,在化学试剂合成的NCM(Ni,Co,Mn)材料中预先引入最优含量的Na⁺,占据部分Li⁺位点,实现具有更低Li⁺/Ni²⁺阳离子混排的稳定结构,从而提高其电化学性能。结果表明,当Na⁺掺杂量为1%(质量分数)(x=0.01)时,获得的NCM-Na正极材料在1C电流密度下,循环100次后容量保持率从76.84%提高至89.21%。特别是在5C大电流密度下,循环200次后,可逆放电比容量依然维持在110 mA·h·g^-1。这为杂原子掺杂耦合材料化冶金开发低成本、高性能锂离子电池三元LiNi_1/3Co_1/...     

Mg-Y共掺杂高电压钴酸锂正极材料的合成及其性能研究

将Co₃O₄、Li₂CO₃、Mg(OH)_2和Y₂O₃按一定化学计量比称取并混合均匀后,采用高温固相法合成LiCo_1-x-yMg_xY_yO₂正极材料并探究了Mg-Y共掺杂对钴酸锂高电压性能的影响。采用X射线衍射(XRD)和扫描电镜(SEM)分别表征其晶体结构和形貌。LiCo_1-x-yMg_xY_yO₂正极材料高电压性能测试结果表明选择Mg掺杂量为0.2%(质量分数),当Y的掺杂量为0.10%(质量分数)时,在3.0~4.6 V电压范围内0.5 C倍率下的初始放电比容量为212 mAh/g,循环50周的容量保持率为96.3%。4 C大倍率下,未掺杂Y元素样品容量保持率为54.9%,相比之下Y掺杂后容量保持率提高为60.4%。     

富镍三元层状正极材料表面残碱去除工艺：研究进展、挑战及展望

富镍LiNi_1-x-yCo_xMn_yO₂(NCM)/LiNi_1-x-yCo_xAl_yO₂(NCA)三元层状正极材料因其比容量高、成本低等优势，被认为是最具前景的锂电池正极材料之一。但由于其对空气中H₂O和CO₂的敏感效应，表面易生成残碱化合物LiOH/Li₂CO₃(RLCs)，而RLCs的存在会急剧恶化富镍三元材料热稳定性能和电化学性能，致使其大规模商业化应用面临严峻挑战。本文首先综述了RLCs的组成和形成机理，并系统概括RLCs引起的微裂纹扩展、Li⁺/Ni²⁺混排、界面副反应和晶格相变等材料失效机制以及常用RLCs去除策略；重点阐述去离子水洗涤、无水乙醇洗涤、溶液洗涤及后续一体化处理等三种RLCs去除工艺的研究进展及对材料结构、形貌及电化学性能的影响机理。最后，归纳总结上述溶液洗涤去...     

原位掺杂的高镍正极材料LiNi0.92Co0.039Mn0.038Zr0.003O2的烧结工艺与性能

采用共沉淀-固相烧结法成功制备了锆离子原位掺杂的高镍正极LiNi_0.92Co_0.039Mn_0.038Zr_0.003O₂,通过X射线衍射(XRD)、扫描电镜(SEM)、电化学阻抗(EIS)、循环伏安(CV)和恒流充放电测试等探究了不同烧结温度、烧结时间以及锂配比对高镍正极材料的结构及电化学性能的影响。结果表明：当烧结温度为720℃、烧结时间为18 h、锂配比为1∶1.02时，烧结得到的材料具有最佳的电化学性能。在30℃、0.1 C的测试条件下，其首次放电比容量为234.5 mAh·g^-1,首次库伦效率为89.9%;其在1 C倍率下循环100次后容量保持率为98.6%。     

固体氧化物燃料电池La0.6Sr0.4Co0.2Fe0.8-xScxO3-?阴极材料的晶体结构与电化学性能

采用溶胶-凝胶法合成了Sc掺杂La_0.6Sr_0.4Co_0.2Fe_0.8-xSc_xO_3-δ(LSCFSc_x,x=0,0.04,0.08)阴极粉体,系统分析了LSCFSc阴极材料的晶体结构、表面元素化学形态、催化活性及电化学性能。XRD结果表明,LSCF为立方结构,Sc³⁺掺杂后LSCFSc阴极材料由立方相向六方结构转变。LSCFSc阴极材料的电导率随着Sc³⁺的掺杂而降低,在300～800℃温度范围内LSCFSc_0.08阴极样品的电导率仍大于100 S/cm。XPS结果表明Sc³⁺掺杂提高了LSCFSc阴极材料表面吸附氧(OAds)的含量,LSCFSc_0.08阴极材料在800℃测得的极化面电阻RASR为0.026Ω·cm²,相比LSCF阴极材料RASR降低了约87.7%,显著改善了LSCFSc阴极材料对氧气...     

锂离子电池富镍正极基础科学问题：前驱体高温锂化过程结构演变及调控

为合成高性能富镍正极,需采用较优的煅烧温度、煅烧时间、降温程序等锂化特定形态的氢氧化物前驱体,以可控形成具有较优晶体结构及晶粒形态的正极材料。然而,由于煅烧过程涉及参数多且变化范围大,合理设计制备具有理想结构和形态的富镍正极所需煅烧工艺仍然具有挑战性。为此,需深入理解前驱体和锂盐高温煅烧为正极过程的物相、结构、形貌等的演变方式及形成规律,以为富镍正极煅烧工艺设计及材料定向调控提供参考。本文首先介绍了前驱体高温锂化过程物相、结构演变及反应机制,包括从热力学相平衡角度简要分析的相组成变化、基于原位测试及理论计算分析的前驱体锂化过程反应机制及物相演变以及降温过程发生的显著影响富镍正极材料性能的表面重构现象。其次,介绍了前驱体锂化过程的形貌影响因素及演变方式。最后,对富镍正极煅烧过程面临的问题进行了探讨。本文系统总结前驱体煅烧过程结构演变及调控规律,以期为相关专业人员开发富镍正极提供参考。     

超声振动对含LPSO结构的Mg98Y1.0Ni0.5Al0.5合金显微组织与力学性能的影响(英文)

低Y、Ni含量的LPSO结构增强镁合金具有低成本、优异力学性能的特点。为进一步提升其综合力学性能,掺杂Al元素及熔体超声振动处理是可行的途径。通过扫描电子显微镜、能谱分析、透射电子显微镜、X射线衍射和纳米压痕测试研究掺杂Al元素后低Y、Ni含量的Mg98Y1.0Ni0.5Al0.5合金的显微组织,对比超声振动对显微组织与力学性能的影响。掺杂Al后LPSO结构的含量降低,且在块状LPSO结构相邻处析出圆整的Al₂NiY相。Al₂NiY相与LPSO结构和Mg基体在界面处均不共格。通过对熔体施加超声振动处理后,Al₂NiY相被有效细化为短片状,并均匀分布在基体中,阻碍微裂纹的产生和扩展,从而提高Mg₉₈Ni_0.5Y_1.0Al_0.5合金的力学性能。与未经超声处理Mg₉₈Ni_0.5Y_1.0Al_0.5合金相比,其极限抗拉强度和伸长率提升至187 MPa和7.9...     

镍、锰掺杂LiFePO_4电池正极材料的合成和电化学性能研究

以Li OH·H2O,Fe SO4·7H2O,H3PO4、Ni SO4、Mn SO4为原料,采用水热法合成了Li Fe1-xNixPO4和Li Fe1-xMnxPO4。采用XRD、FESEM分析了正极材料的组成、结构及形貌,利用电池测试仪测试了正极材料的电化学性能。结果表明:镍、锰掺杂Li Fe PO4具有较好的充放电性能。Li Fe0.9Mn0.1PO4的首次充放电比容量分别为143.5、143 m Ah/g,Li Fe0.95Ni0.05PO4的首次充放电比容量分别为132、131 m Ah/g,离子掺杂能显著提高材料的充放电比容量。     

S掺杂2H-CuGaO2结构与性能的第一性原理研究

基于第一性原理的密度泛函理论平面波超软赝势方法,研究不同浓度S掺杂对2H-CuGaO₂能带结构和电子特性的影响规律。结果表明,掺杂后2H-CuGaO₂仍是间接带隙半导体,且带隙值随着掺杂浓度增加而增加;掺杂过程形成费米能级,对2H-CuGaO₂导电性产生影响。     

锂离子电池富锂材料Li[Li0.2Ni0.2Mn0.6]O2的制备及掺杂改性

以乙酸盐为原料,采用喷雾干燥法制备层状α-NaFeO2结构的富锂正极材料Li[Li0.2Ni0.2Mn0.6]O2及掺杂Cr的Li[Li0.2Ni0.15Cr0.1Mn0.55]O2。采用X射线衍射、扫描电镜、半电池充放电和电化学阻抗谱等方法研究材料的物相、结构、形貌及电化学性能。结果表明:Cr掺杂使材料的颗粒变粗,但不改变材料的结构,而使材料的层状特征更为明显;Cr掺杂后材料的电化学性能得到明显改善,电荷转移阻抗Rct从275.0降低到105.0,循环稳定性和倍率性能均有所改善,Li[Li0.2Ni0.15Cr0.1Mn0.55]O2材料1C倍率下的放电比容量为140.0 mA.h/g,循环50次后放电比容量为133.7 mA.h/g,远高于未掺杂Cr材料的比容量,未掺杂Cr材料在1C倍率下放电比容量为107.1mA.h/g,循环50次后放电比容量为102.1 mA.h/g。     

室温固相法制备Co/Mn包覆LiNiO_2正极材料(英文)

重点研究了室温固相法Co/Mn氢氧化物包覆Ni(OH)2的机理.采用XRD,SEM,TEM和EDS分析检测手段分析了未包覆与表面包覆材料的结构、形貌和表面成分.TEM实验结果表明,LiNiO2颗粒表面包覆了一薄层化合物;XPS实验结果表明,LiNiO2颗粒表面包覆了Co/Mn元素;SEM和EDS实验结果进一步表明,球形LiNiO2颗粒表面均匀包覆了Co/Mn化合物层.电化学性能测试结果表明,经Co/Mn包覆的LiNiO2正极材料显示了优越的循环性能.     

Synthesis and characterization of LiNi0.95-xCoxAl0.05O2 for lithium-ion batteries

Samples of LiNi0.95-xCoxAl0.05O2 （x = 0.10 and 0.15） and LiNiO2, synthesized by the solid-state reaction at 725℃ for 24 h from LiOH-H2O, Ni2O3, Co2O3, and AI（OH）3 under an oxygen stream, were characterized by TG-DTA, XRD, SEM, and electrochemical tests. Simultaneous doping of cobalt and aluminum at the Ni-site in LiNiO2 was tried to improve the cathode performance for lithium-ion batteries. The results showed that co-doping （especially, 5 at.% A1 and 10 at.% Co） definitely had a large beneficial effect in increasing the capacity （186.2 mA.h/g of the first discharge capacity for LiNio.s.42OoaoAlo.0502） and cycling behavior （180.1 mA-h/g after 10 cycles for LiNio.85CooaoAlo.osO2） compared with 180.7 mA.h/g of the first discharge capacity and 157.7 mA.h/g of the tenth discharge capacity for LiNiO2, respectively. Differen- tial capacity versus voltage curves showed that the co-doped LiNio.95_xCoxmlo.osO2 had less intensity of the phase transitions than the pristine LiNiO2.     

Electrochemical performance of LiFePO4 cathode material for Li-ion battery

In the search for improved materials for rechargeable lithium batteries, LiFePO4 offers interesting possibilities because of its low raw materials cost, environmental friendliness and safety. The main drawback with using the material is its poor electronic conductivity and this limitation has to be overcome. Here Al-doped LiFePO4/C composite cathode materials were prepared by a polymer-network synthesis technique. Testing of X-ray diffraction, charge-discharge, and cyclic voltammetry were carried out for its performance. Results show that Al-doped LiFePO4/C composite cathode materials have a high initial capacity, good cycle stability and excellent low temperature performance. The electrical conductivity of LiFePO4 material can be obviously improved by doping Al. The better electrochemical performances of Al-doped LiFePO4/C composite cathode materials have a connection with its conductivity.     

Synthesis and electrochemical properties of Li[NixCoyMn1-x-y]02 (x, y=2/8, 3/8) cathode materials for lithium ion batteries

The uniform layered Li(Ni2/8Co3/8Mn3/8)O2, Li(Ni3/8Co2/8Mn3/8)O2, and Li(Ni3/8Co3/8Mn2/8)O2 cathode materials for lithium ion batteries were prepared using the hydroxide co-precipitation method. The effects of calcination temperature and transition metal contents on the structure and electrochemical properties of the Li-Ni-Co-Mn-O were systemically studied. The results of XRD and electrochemical performance measurement show that the ideal preparation conditions were to prepare the Li(Ni3/8Co3/8Mn2/8)O2 cathode material calcined at 900℃ for 10 h. The well-ordered Li(Ni3/8Co3/8Mn2/8)O2 synthesized under the optimal conditions has the I003/I104 ratio of 1.25 and the R value of 0.48 and pedance of 558 Ω after the first cycle. The decrease of Ni content results in the decrease of discharge capacity and the bad cycling perform-ance of the Li-Ni-Co-Mn-O cathode materials, but the decreases of Mn content and Co content to a certain extent can improve the electro-chemical properties of the Li-Ni-Co-Mn-O cathode materials.     

Preparation of LiNi_(1-y)Co_yO_2 in certain oxygen pressure

1　INTRODUCTIONLi ionbatteryisthenewlydevelopedrecharge ablebatterysubsequenttoCd/NiandMH/Nibat tery .Itshighenergypropertyisnotonlyfitforthepowersupplyofsmallscaleelectricproductdevelop ingattopspeed ,butalsofitforthepowersupplyofthelargescalemotivepowertooltoavoid pollutingtheenvironment .Thepreparationofcathodematerialisthekeylinksforthedevelopmentoflithiumionbattery .Atpresent ,thecathodematerialsusedinlithiumionbatteryareLiCoO2 ,LiNiO2 ,LiMn2 O4 andtheirderivatives .Amongthem ,…     

Al掺杂Li_2MnSiO_4锂离子电池正极材料的合成和电化学性能

以Li2SiO3、Mn(CH3COO)2.4H2O和Al(OH)3为原料,用传统高温固相合成法成功制备出Li2Al0.1Mn0.9SiO4锂离子电池正极材料。采用XRD、FESEM分析了正极材料的相组成、结构和形貌,利用电池测试仪测试了正极材料的电化学性能。研究结果表明,固相合成的产物主相为Li2Al0.1Mn0.9SiO4,同时存在少量的杂质,产物表面形貌为非球形颗粒,颗粒尺寸为100～500 nm。实验结果表明,Al掺杂后,正极材料的可逆容量和循环寿命都得到提高。正极材料电化学性能提高的机理在于Al掺杂稳定了Li2MnSiO4正极材料的结构。     

锂离子电池及相关材料进展

新能源技术对人类社会未来可持续发展至关重要,锂离子电池可望大规模应用于电动汽车和太阳能、风能等清洁电能的储存。电动汽车电池还面临重量、体积、寿命、安全、成本和系统可靠性等诸方面的挑战。评述了钴酸锂、锰酸锂、三元材料和磷酸铁锂等正极材料;石墨、钛酸锂等负极材料;电解质材料和隔膜材料等的研究和应用,重点介绍了正极材料的掺杂和表面修饰改性技术。并对电池技术的进步和新一代锂离子电池应用于电动车辆和智能电网的前景进行了展望。     

Li 含量对球形富锂正极材料结构和电化学性能的影响

富锂正极材料已经成为高能量密度锂离子电池最具有前景的正极材料之一。然而,富锂正极材料电化学性能对其本体和表面的局域结构很敏感,而这些结构跟材料的合成过程密切相关。在目前的工作中,从合成的角度提出了新的思路,Li含量x将影响着富锂Li1.2x Mn0.54 Ni0.13 Co0.13 O2材料的结构特性和电化学性能。基于电化学,XRD,Raman, XPS技术的分析结果,改变Li含量将在材料的本体和表面产生尖晶石相和Li2 CO3物种,会造成所合成的材料局部组分发生变化,进而影响其电压容量曲线。实验结果表明,在正极材料合成的过程中,相比于其他含量,Li含量过量5%(摩尔分数)所合成的样品表现出更好的电化学性能,放电容量高达270 mAh/g。     

废旧LiCoO2材料再生LiNi0.8Co0.1Mn0.1O2正极材料及性能研究

针对废旧锂离子电池数量不断增加的现状,对废旧LiCoO2电池的回收和再生流程进行探究。以废旧LiCoO2电池为原料,通过预处理,酸浸,共沉淀步骤,实现了LiNi0.8Co0.1Mn.1O2正极材料的再生。ICP-OES分析浸出液中的元素含量,SEM和XRD表征材料形貌和结构,扣式电池的电化学测试定量分析材料的电化学性能。研究表明,利用浸出液可以再生形貌和层状结构良好的正极材料,在0.2C,2.8~4.3V电压范围内进行充放电循环测试,首周放电比容量可达到210.8 mAh/g,经过50周充放电循环后的容量保持率为87%,表现出良好的循环稳定性,为废旧锂离子电池的再生提供支撑和发展方向。     

XRD simulation study of doped LiFePO4

LiFePO₄ has become a highly promising cathode material for use in the next generation of lithium-ion batteries, in which metal-doping is typically employed to improve the electrochemical properties. However, it is always difficult to resolve the issue that how the doping element and its position cause the microstructural changes and eventually influence the material properties. In this work, the X-ray diffraction (XRD) patterns of a series of metal-doped LiFePO₄ were simulated by software MS Reflex to investigate those factors since XRD is a typical technique for the study of crystal structures. The effect of simulation conditions, doping position, and types of doping elements were discussed. The results revealed that: (1) the suitable step size should be 0.02° or less, and the simulation position had little influence on the XRD pattern; (2) the peak intensity changed with doping position, and had been affected more evidently at the Li-site compare with the Fe-site; (3) there was a close relationship between the doping elements and peak intensities in XRD patterns, and the variation degree of the peak intensity increased linearly with the atomic number of doping elements.