锂离子电池用锰酸锂(LiMn_2O_4)的研究与发展

详细论述了近年来用作锂离子电池正极材料的尖晶石型锰酸锂(LiMn_2O_4)的制备方法,以及国内外对锰酸锂正极材料通过包覆、镀膜等表面处理和掺杂金属离子、非金属离子及阴-阳离子复合掺杂等方法进行改性的研究。探讨了这些改性方法提高LiMn_2O_4正极材料电化学性能的机制。表面处理和掺杂提高了锰酸锂的循环性能,但会使其初始容量下降,因此要对不同的正极材料进行混合。最后提出了尖晶石型锰酸锂正极材料的主要发展方向。     

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。     

稀土掺杂在锂离子电池中的应用进展

阐述了锂离子电池技术发展的重要性,综述了稀土掺杂在锂离子电池正极材料、负极材料及固体电解质中的应用.重点介绍了稀土掺杂在锂离子电池正极材料中的应用,并提出稀土掺杂有利于电池比容量的提高,从而有利于进一步提高锂离子电池的比能量和循环性能.展望了稀土掺杂在锂离子电池中的发展前景,并认为这些技术将是未来锂离子电池研究的重要方向.     

尖晶石锰酸锂制备及其电化学性能的研究

锰酸锂被认为是取代商品锂离子电池正极材料LiCoO2的候选材料,以二氧化锰、碳酸锂为原料,在空气气氛下进行烧结,控制烧结温度和时间,制备锂离子电池正极材料锰酸锂。用X射线衍射仪、电子扫描电镜对产物的结构特征、微观表面形貌和恒流充放电性能进行了表征。结果表明:所制得的正极材料为尖晶石型锰酸锂,结晶度高、无杂质相、材料颗粒的粒径均匀,首次充放电比容量为117.3 mAh/g(0.2C,3.3～4.4V);50次循环后,放电比容量为107.9 mAh/g,不可逆容量损失为9.4 mAh/g,比容量保持率为92.0%,得到了很好的综合电化学性能。     

锂离子电池预锂化技术研究进展

近年来，随着锂离子电池应用日益广泛，迫切需要开发高能量密度的锂离子电池来满足日益苛刻的动力、储能电池的性能要求。采用预锂化技术对锂离子电池电极材料进行处理，可以提升锂离子电池的首次库伦效率，减小首次充放电过程中的锂不可逆损失，对高容量的硅等材料的工业应用至关重要。本文综述了近些年来锂离子电池预锂化技术的研究进展，主要阐述了化学补锂法、电化学补锂法、添加剂补锂、过锂化正极、正极添加剂等几种常见的补锂技术研究，并对未来预锂化技术发展进行了展望。     

标准助推新能源汽车产业发展——YS/T 1448-2021《包覆型镍钴锰酸锂》标准解读

<正>行业标准YS/T1448-2021《包覆型镍钴锰酸锂》于2021年12月2日发布,2022年4月1日实施,该标准是新能源汽车产业链上的正极材料标准,对于推动我国新能源汽车产业的高质量发展具有重要意义,本文将对YS/T1448-2021《包覆型镍钴锰酸锂》进行标准解读。在新能源汽车产业的带动下,近年来我国锂离子电池的产量和市场需求量迅猛增长。正极材料是锂离子电池的核心和关键材料,     

锂离子电池正极材料LiFePO4改性研究

介绍了LiFePO4正极材料的结构特点和反应机理,详细讨论了金属离子掺杂、碳包覆和控制活性材料的尺寸等改性研究对LiFePO4材料的电化学性能的影响.从而进一步优化高性能锂离子电池正极材料的改性过程,促进锂离子电池性能的改善.     

锂离子电池LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2废料直接回收及材料再生性能

通过直接热处理以及补充锂元素二次烧结的方法对锂离子电池三元镍钴锰废料进行回收,并将其重新作为锂离子电池正极材料进行应用。采用扫描电镜、红外光谱、热重、电感耦合等离子体以及电化学测试等方法对材料性能进行检测。结果表明:温度高于700℃时可以有效去除报废材料中的PVDF,高温烧结可以一定程度上修复材料容量,而通过补充锂元素进行二次烧结的方法可以有效恢复废料性能,具有商业应用价值。此方法工艺简单,可以为锂离子电池正极层状材料的回收提供参考。     

液相Al3+掺杂LiAlxMn2-xO4的化学合成及其电化学性能

采用工业上常用的碳酸锰热解法制备锰氧化物前驱体,与Li2CO3混合后焙烧得到锂离子电池正极材料LiMn2O4,并在碳酸锰制备过程中掺入铝离子制备LiAlxMn2?xO4(x=0.01,0.02,0.03,0.05,0.1)。通过X射线衍射(XRD)和扫描电镜(SEM)对样品进行表征,并对合成材料在常温和高温(55℃)下的电化学性能进行研究。结果表明:合成的前驱体及锰酸锂材料均无杂相;随着Al3+掺杂量的增加,LiAlxMn2-xO4颗粒尺寸不断长大;材料的首次充放电比容量随Al3+掺杂量的升高而下降,但循环性能提高;Al3+的掺入极大地提高了材料的循环性能,尤其是在高温条件下,当掺杂量x=0.05时,1C倍率下循环100次容量的保持率由未掺杂的72.2%升高到90.7%。     

模拟废旧锂离子电池湿法冶金浸出液再生铝掺杂LiNi0.5Co0.2Mn0.3O2正极材料

采用共沉淀法制备均相Al掺杂的LiNi0.5Co0.2Mn0.3O2正极材料,以利用Al对再生镍钴锰(NCM)正极材料的正面改性作用,并改善锂离子电池回收过程中繁琐和高成本的除杂过程.当浸出液中的Al3+含量为过渡金属(Ni、Co和Mn)总量的1％(摩尔分数)时,制备的Al掺杂NCM正极材料中晶格氧和Ni2+的浓度增加...     

Insertion/removal kinetics of lithium ion in spinel LiCuxMn2-xO4

The insertion/removal processes of lithium ion in spinel lithium manganese oxide（LiMn204） and copper doped spinel lithium manganese oxide （LiCuxMn2-xO4） on a powder microelectrode were studied by electrochemical impedance spectroscopy（EIS）, cyclic voltammetry（CV） and X-ray diffractometry（XRD）. The insertion/removal process of lithium ion in the spinel oxides consists of three steps： charge transfer of lithium ion on the surface of the spinel oxides, diffusion and occupation of lithium ion in the lattice of the spinel oxide. Similar to chromium, the doping of copper in spinel lithium manganese oxide results in the increase of the charge transfer resistance and the double layer capacitance for lithium insertion or removal, and the decrease of the diffusion coefficient of lithium ion in the lattice of spinel oxide. However, the insertion capacitance, a parameter reflecting the occupation of lithium ion in the lattice of the spinel oxide, is hardly influenced by the doping of copper. The influence of the doped copper on the kinetic process of lithium insertion/removal in spinel lithium manganese oxide is related to the contraction of spinel lattice.     

Effects of Mn-Precursor on Performances of LiMn2O4 Cathode Material for Lithium Ion Battery

通过固相烧结工艺,制备了铝掺杂的Li Mn2O4锂离子电池正极材料。其中球型化及鳞块状的Li Mn2O4分别由Al共沉积的锰氧化物(CMO)前驱体及电解二氧化锰(EMD)前驱体制备。通过X射线衍射仪、扫描电子显微镜、电感耦合等离子光谱仪及方型铝壳全电池充放电测试等手段对试样的物化指标进行了测试。结果表明两组试样都为纯相,同时以CMO为前驱体制备的Li Mn2O4材料具备较好的球型度,更高的振实密度以及更优异的电化学性能。     

动力锂离子电池正极材料的研究评述

通过衡量锂离子电池正极材料的安全性,认为LiMn2O4和LiMPO4可以作为动力电池的正极材料,综述LiMn2O4和LiMPO4正极材料的研究现状,重点对各种材料的合成、结构和性能进行总结和探讨.从目前来看,LiMn2O4仍然是主流的动力电池正极材料,但从长远来看,LiMPO4特别是Li3V2(PO4)3是动力锂电池正极材料的发展趋势.     

镍镁掺杂LiFePO4的电子结构

采用基于密度泛函理论的第一性原理研究锂离子电池正极材料LiFePO4掺杂Ni和Mg的电子结构。结果表明:Ni氧化物的电子结构和能量性质受d轨道中电子影响,用于掺杂改性时,结构稳定,带隙降低使电子电导率增加,充放电速率提高;Mg掺杂改性时,当掺杂在Li位时,带隙和总能均降低,同时Li离子的扩散运动也提高,有利于改性,而在Fe位掺杂时,费米面附近Fe-d轨道中电子影响能带,使带隙增加,不利于电子电导,键的布居分析也表明Li—O共价性增强,不利于离子扩散,即不利于改性。因此,通过掺杂可对LiFePO4的微观结构产生影响,从而影响其电化学性能,但这种微观结构主要受d轨道中电子运动对费米面附近能带的影响,而与掺杂离子的化合价和半径无关。     

Characterization of alkaline-earth oxide additions to the MnO2 cathode in an aqueous secondary battery

The effect of alkaline-earth oxide additions on aqueous rechargeable battery is investigated using microscopic and spectroscopic techniques. The alkaline-earth oxide additions such as magnesium oxide (MgO) and barium oxide (BaO) were physically mixed to the manganese dioxide (MnO₂) cathode of a cell comprising zinc as an anode and aqueous lithium hydroxide as the electrolyte. The results showed that such additions greatly improved the discharge capacity of the battery (from 145 to 195 for MgO and 265 mAh/g for BaO). Capacity fade with subsequent cycling is reduced only for MgO but not for BaO. With an aim to understand the role of these additives and its improvement in cell performance, we have used microscopy, spectroscopy, ion beam analysis and diffraction based techniques to study the process. Transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy analysis (EDS) results showed evidence of crystalline MnO₂ particles for MgO as additive, whereas, MnO₂ particles with diffused structure leading to mixture of phases is observed for BaO additives which is in agreement with X-ray diffraction (XRD) data. This work relates to improvement in the electrochemical behaviour of the Zn-MnO₂ battery while the MgO additive helps to reduce the formation of manganese and zinc such as hetaerolite that hinders the lithium intercalation.     

金属阳离子在锂辉石浮选中的活化行为及作用机理

在油酸浮选锂辉石体系中分别加入Ca^2+、Al^3+、Fe^3+离子,通过单矿物浮选试验、金属离子吸附量检测、金属离子水解组份浓度计算、矿物表面动电位测试、红外光谱检测以及量子化学模拟计算研究Ca^2+、Al^3+、Fe^3+离子对锂辉石浮选的活化行为和作用机理。结果表明:Ca^2+离子的最佳活化区间为pH大于12的强碱性条件,Al^3+离子的最佳活化pH为6.47,而Fe^3+离子的最佳活化pH为7.25;在这些pH区间内,锂辉石浮选回收率和金属离子吸附量均达到最大值。在锂辉石浮选过程中起活化作用的有效组份为它们分别对应的氢氧化物沉淀。Ca^2+、Al^3+、Fe^3+离子可使锂辉石表面动电位向正值方向显著偏移;Ca^2+离子在锂辉石表面双电层的外层发生静电吸附,Al^3+和Fe^3+离子在锂辉石表面双电层的内层发生特性吸附。钙原子与锂辉石矿物表面吸附后形成的Ca—O键的键强较小,以离子键为主;铁原子与矿物表面形成Fe—O化学键的键强较大,含有一定的共价键组份;而铝原子与矿物表面吸附后形成的Al—O键的键长、键强等参数介于钙、铁的参数之间。油酸在Ca^2+活化后的锂辉石表面发生了化学吸附和少量的物理吸附,而在Al^3+、Fe^3+活化后的锂辉石表面发生了较为强烈的化学吸附。     

二次锂电池负极材料电化学

二次锂电池的优点是高体积、高质量比容量、长循环寿命、低自放电速率，是环保型电动车驱动电源的理想候选之一。二次锂电池负极材料经历了第1代的金属锂、第2代的碳材料，即石墨嵌入化合物GIC，目前研究的焦点是锂合金负极材料。本文在总结了金属锂和碳材料的同时，综述了3年来负极锂合金材料的研究状况。     

阳极电沉积法制备锰类氧化物涂层电极的研究

综合论述了阳极电沉积法制备金属氧化物涂层电极的机理研究与发展现状,重点围绕低廉金属锰类氧化物与掺杂Mo、W、Co、Fe、Ni等的锰类氧化物涂层电极的阳极电沉积机制及研究现状进行了阐述,并总结了主要制备参数如锰离子浓度、电流密度、阳极电沉积温度及pH值等对阳极电沉积的影响规律.最后对其未来的发展及应用前景进行了展望.     

Co-intensification of gold leaching with heavy metals and hydrogen peroxide

Co-intensification was researched to accelerate gold leaching with regards to its electrochemical nature by using anodic intensifiers of heavy metal ions (Pb2+, Bi3+, Tl+, Hg2+ and Ag+) on the basis of hydrogen peroxide assistant leaching on three different types of materials which were classified as a refractory sulphide gold concentrate, an easily leachable sulphide gold concentrate, and a low grade oxide gold ore according to their leaching characteristics. The results showed that, favorable co-intensification effects on the three materials were obtained and leaching time of gold was effectively shortened to no longer than 12 h from 16 to 24 h for hydrogen peroxide assistant leaching. For the five tested heavy metal ions, Bi3+and Tl+ presented co-intensifying effect on all the three materials, and Hg2+ caused co-intensifying effect on both refractory and easily leachable sulphide gold concentrates, and Pb2+ and Ag+ only had co-intensifying effect on the easily leachable sulphide gold concentrate.     

Ingenious Interlacement of CoNiO2 on Carbon Nanotubes for Highly Stable Lithium-Ion Batteries

Nickel-cobalt oxide is considered as a promising anode for lithium-ion battery, owing to its high specific capacity, simple synthesis process and high safety. However, like most transition metal oxide anode materials, nickel-cobalt oxide suffers from poor conductivity, easy agglomeration and large volume expansion in the charging and discharging process, causing an inferior cycling lifespan. Here we report a structure design that CoNiO₂ particles are ingeniously interlaced on carbon nanotubes by a simple solvothermal method. These nanotubes are irregularly intertwined to obtain an independent electrode structure with high electronic conductivity, which can also alleviate the notorious volume expansion. Consequently, the corresponding lithium-ion battery shows superior electrochemical performance. It provides a discharge capacity of 1213.7 mAh g⁻¹ at 0.5 A g⁻¹, and can be stable over 100 cycles with a capacity retention of 96.45%. Furthermore, the battery can also deliver a reversible capacity of 544.8 mAh g⁻¹ at the high current density 3 A g⁻¹. This work provides a unique idea for the performance improvement of nickel-cobalt oxide anode for lithium-ion batteries.