Ni2+掺杂对Li3V2（PO4）3电化学性能的影响

采用X射线衍射(XRD)、透射电镜(TEM)和电化学方法,研究Ni2+掺杂对正极材料Li3V2(PO4)3的结构、形貌和电化学性能的影响。结果表明:掺杂适量的Ni2+不会改变Li3V2(PO4)3的单斜晶系结构,但可提高材料的电导率,抑制电池在充放电过程的极化。在室温下,Li3(Ni0.05V0.95)2(PO4)3以0.1C倍率放电的初始比容量为115mA.h/g,放电倍率从0.1C增加到0.4C循环60次后,比容量衰减率仅为2.7%,而未掺杂原样Li3V2(PO4)3的初始比容量为129 mA.h/g,60次循环后比容量衰减率约为30.3%;当放电倍率增至1C时,80次循环后,Li3(Ni0.05V0.95)2(PO4)3比容量为99.8 mA.h/g,而原样的比容量为84.1 mA.h/g;当放电倍率增至5C时,循环120次后,Li3(Ni0.05V0.95)2(PO4)3比容量为67.7 mA.h/g,而原样的比容量降为0。循环伏安和交流阻抗测试表明,Li3(Ni0.05V0.95)2(PO4)3的可逆性明显优于Li3V2(PO4)3的可逆性。     

Surface Modification of Li1.6(Fe0.2Ni0.2Mn0.6)O2.6 by V2O5- Coating

在采用低温共沉淀-水热-煅烧法合成锂离子电池Fe-Ni-Mn体系正极材料Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的基础上,对合成的材料Li1.6(Fe0.2Ni0.2Mn0.6)O2.6进行V2O5的包覆改性研究,以提高材料Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的首次放电比容量和循环性能。用XRD、SEM、TEM、ICP光谱和恒流充放电测试研究包覆材料的结构和电化学性能。结果表明,V2O5包覆并没有改变材料的晶体结构,只存在于材料的表面,与未包覆的材料相比,V2O5包覆后的材料具有更好的首次放电容量和容量保持率。50周循环后,添加质量分数3%V2O5样品Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的放电比容量可以维持在200.3 mAh/g,大于未添加V2O5样品Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的194.0 mAh/g。CV测试表明,包覆层的存在有效抑制了材料层状结构的转变及电极与电解液的负反应。     

固相-水热法制备LiFePO4-Li3V2（PO4）3复合材料及其电化学性能（英文）

分别采用固相-水热法和球磨法制备磷酸亚铁锂-磷酸钒锂复合正极材料(LiFePO4-Li3V2(PO4)3)。电化学性能测试表明,LiFePO4-Li3V2(PO4)3复合正极材料的电化学性能远远高于 LiFePO4和 Li3V2(PO4)3单独作为正极材料的性能,并且以固相-水热法制备的复合材料性能优于以球磨法制得的复合材料。研究发现 LiFePO4-Li3V2(PO4)3复合材料有 4 个氧化还原峰,相当于 LiFePO4 和 Li3V2(PO4)3 氧化还原峰的叠加。采用固相-水热法制备的LiFePO4-Li3V2(PO4)3 复合材料形貌较为规则,且有新相物质产生,这是导致其电化学性能较好的原因。     

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.     

高容量锂离子电池正极材料Li1+xV3O8的制备及改性研究

采用一种新型有机酸为络合剂制备正极材料Li1 xV3O8,并用自制的复合纳米凝胶聚合物电解质,组装的扣式电池具有高的比容量和好的循环性能,正极材料Li1 xV3O8在2.2～4.2 V之间放电曲线中电压平台变的平坦,改变了通常情况下正极材料Li1 xV3O8的放电曲线形状.实验表明,复合纳米凝胶聚合物电解质和新型络合剂制备的正极材料Li1 xV3O8在一定程度上可以减缓电池放电时的电压下降,使电池的容量得到明显的提高.     

Li3Ni0.1V1.9（PO4）3的电化学性能研究

采用X射线衍射和电化学方法,研究了正极材料Li3Ni0.1V1.9(PO43)的结构和电化学性能。结果表明:Li3Ni0.1V1.9(PO43)具有单斜晶系结构。在室温下,以0.1C倍率放电时Li3Ni0.1V1.9(PO4)3的初始比容量为115mAh/g,从0.1C增加到0.4C经过60次循环后,比容量保持率为97.3%,而未掺杂镍的Li3V2(PO4)3,初始比容量为129mAh/g,60次循环后,比容量保持率仅为69.7%。循环伏安和交流阻抗测试表明,Li3Ni0.1V1.9(PO4)3有较低的极化电阻和较好的可逆性。     

层状LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料的多元掺杂改性

采用共沉淀法制备锂离子电池掺杂型层状LiNi1/3Co1/3Mn1/3-xMxO2(M=Mg、Al、Cr)正极材料。采用X射线衍射、扫描电镜、充放电实验和交流阻抗实验对LiNi1/3Co1/3Mn1/3-xMxO2正极材料的结构、形貌、电化学性能以及动力学参数进行表征。结果表明:当掺杂量x=0.05时,Mg2+、Al3+掺杂的正极材料在2.8～4.3V、0.1C下的首次放电比容量分别为139.2、151.6mA·h/g,20次循环后的容量保持率分别为98.8%和96.7%;掺杂Mg2+或Al3+均能提高LiNi1/3Co1/3Mn1/3O2的交换电流密度和锂离子扩散系数。结合实验结果和掺杂离子的离子半径和化学稳定性,解释了掺杂离子在LiNi1/3Co1/3Mn1/3O2晶格中的占位及其在充放电过程中的作用。     

锰掺杂对锂离子电池正极材料Li3V2（PO4）3/C性能的影响（英文）

采用溶胶-凝胶法合成Li3V2-2/3xMnx(PO4)3(0≤x≤0.12)。采用XRD、SEM、XPS、恒流充放电和电化学阻抗谱(EIS)研究Mn掺杂对Li3V2(PO4)3/C结构和电化学性能的影响。XRD研究表明:掺杂少量的Mn2+不会影响材料的结构,所有样品均具有单一相态的单斜结构(P21/n空间群)。XPS分析表明:在Li3V1.94Mn0.09(PO4)3/C中,V和Mn的化合价分别为+3和+2,原料中的柠檬酸在煅烧过程中分解成C而残留在Li3V1.94Mn0.09(PO4)3/C中。电化学测试表明:掺杂Mn改善了电极材料的循环性能和倍率性能,正极材料Li3V1.94Mn0.09(PO4)3/C表现出最好的循环稳定性和倍率性能。在40mA/g的放电电流密度下,循环100次后,Li3V1.94Mn0.09(PO4)3/C的放电容量从158.8mA·h/g衰减到120.5mA·h/g,容量保持率为75.9%,而未掺杂样品的放电容量从164.2mA·h/g衰减到72.6mA·h/g,容量保持率为44.2%。当放电电流密度增加到1C时,Li3V1.94Mn0.09(PO4)3/C的初始放电容量仍能达到146.4mA·h/g,循环100次后,放电容量保持为107.5mA·h/g。EIS测试表明,掺杂适量的Mn2+减小了电荷转移阻抗,这有利于Li+的脱嵌。     

空心聚吡咯/V_2O_5复合材料的制备及其电化学性能

为改善晶态V2O5（c-V2O5）正极材料实际容量较低、循环性能较差等问题,制备了空心球聚吡咯/V2O5复合材料。利用导电吡咯单体（Py）在中空型V2O5层间发生原位氧化聚合反应制备聚吡咯（PPy）/中空型V2O5复合材料（HS-PPy/V2O5）。采用X射线衍射仪（XRD）、扫描电镜（SEM）、透射电镜（TEM）对样品进行表征,采用恒流充放电测试和电化学阻抗（EIS）测试样品的电化学性能。结果表明,Py单体已插入中空型V2O5层间,与纯中空型V2O5相比,制备的HS-PPY/V2O5复合材料比容量虽然有所减小,但是循环稳定性有较大的提高。     

Li3V2(PO4)3/C复合结构正极材料的制备和电化学性能

以柠檬酸为螯合剂和碳源,采用溶胶凝胶法在强弱不同条件下制备锂离子正极材料Li3V2(PO4)3/C.利用XRD、SEM和恒电流充放电等进行测试和表征.结果表明,所有样品为纯相的单斜Li3V2(PO4)3,制备条件的不同不会影响Li3V2(PO4)3正极材料的晶型结构和晶胞参数,但对材料颗粒尺寸有较大影响,加入蔗糖可以抑制颗粒的长大和团聚,从而影响电化学性能;在3.0～4.3 V电压,由于Li3V2(PO4)3结构的稳定性,在低倍率下表现出优异的循环性能;随着颗粒的变大和团聚,材料的倍率性变差,在高倍率下充放电容量衰减快.     

锂离子电池的工作原理与关键材料

锂离子电池具有能量密度高、自放电小和循环寿命长等优点,被广泛用于便携式电子设备和电动汽车等方面,不断推动着社会朝着智能化和清洁化方向发展.简要阐述了锂离子电池的发展历程和工作原理,从材料结构和储锂机制方面对正极材料和负极材料进行分类并综述其性能特点与研究现状,介绍了液态电解液中锂盐、溶剂、添加剂以及固态电解质在锂离子电...     

锗基锂离子电池负极材料的制备及研究进展

随着便携式电子产品及电动汽车的快速发展,提高锂离子电池能量密度和功率密度的研究日益增多,其中负极材料作为锂离子电池必备部件之一已成为重要的研究方向。商用的石墨负极因理论容量较低限制了其应用,锗具有较高的理论比容量和优异的物理化学性质,成为锂离子电池负极材料的研究热点。本文介绍了不同形貌和组成的锗基纳米负极材料的制备方法以及国内外的研究进展,并对未来的发展方向进行了展望。     

Thermal behavior analysis of a pouch type Li[Ni_(0.7)Co_(0.15)Mn_(0.15)]O_2-based lithium-ion battery

Since lithium-ion battery with high energy density is the key component for next-generation electrical vehicles,a full understanding of its thermal behaviors at different discharge rates is quite important for the design and thermal management of lithium-ion batteries(LIBs)pack/module.In this work,a 25 Ah pouch type Li[Ni_(0.7)Co_(0.15)Mn_(0.15)]O_2/graphite LIBs with specific energy of200 Wh kg~(-1)were designed to investigate their thermal behaviors,including temperature distribution,heat generation rate,heat capacity and heat transfer coefficient with environment.Results show that the temperature increment of the charged pouch batteries strongly depends on the discharge rate and depth of discharge.The heat generation rate is mainly influenced by the irreversible heat effect,while the reversible heat is important at all discharge rates and contributes much to the middle evolution of the temperature during discharge,especially at low rate.Subsequently,a prediction model with lumped parameters was used to estimate the temperature evolution at different discharge rates of LIBs.The predicted results match well with the experimental results at all discharge rates.Therefore,the thermal model is suitable to predict the average temperature for the large-scale batteries under normal operating conditions.     

Nb2O5 nanoparticles embedding in graphite hybrid as a high-rate and long-cycle anode for lithium-ion batteries

Lithium-ion batteries(LIBs)have exhibited extraordinary prospects due to their high energy and power density.However,the future development of LIB sis largely i...     

氮掺杂纳米碳改性LiFePO4正极材料的研究进展

锂离子电池是一种高效、清洁的储能装置,在便携式电子产品、储能设施和电动汽车等领域具有广泛的应用前景,对于缓解能源危机、环境污染和优化能源结构等方面具有重要意义。橄榄石型LiFePO_4是最有前途的锂离子电池正极材料之一,但较低的本征电子电导率与锂离子扩散速率限制了其高倍率性能的发挥及在锂离子动力电池中的广泛应用。纳米碳材料,尤其氮掺杂的无定形纳米碳、碳纳米管以及石墨烯等具有电子电导率高,比表面积大,亲和力强以及热、化学稳定性好等特点,在改善LiFePO_4材料性能方面显示出独特的优势。本文从掺杂方法、形貌结构、电化学性能等方面总结氮掺杂纳米碳改性LiFePO_4正极材料的研究进展,并展望其发展前景。     

Antimony-based intermetallic compounds for lithium-ion and sodium-ion batteries: synthesis,construction and application

The development of alternative electrode materials with high energy densities and power densities for batteries has been actively pursued to satisfy the power demands for electronic devices and hybrid electric vehicles. Recently, antimony(Sb)-based intermetallic compounds have attracted considerable research interests as new candidate anode materials for high-performance lithium-ion batteries(LIBs) and sodium-ion batteries(SIBs) due to their high theoretical capacity and suitable operating voltage. However, these intermetallic systems undergo large volume change during charge and discharge processes, which prohibits them from practical application. The rational construction of advanced anode with unique structures has been proved to be an effective approach to enhance its electrochemical performance. This review highlights the recent progress in improving and understanding the electrochemical performances of various Sb-based intermetallic compound anodes. The developments of synthesis and construction of Sb-based intermetallic compounds are systematically summarized. The electrochemical performances of various Sb-based intermetallic compound anodes are compared in its typical applications(LIBs or SIBs).     

Realizing simultaneously enhanced energy and power density fullcell construction using mixed hard carbon/Li_4Ti_5O_(12) electrode

Practical applications of lithium-ion batteries(LIBs) with both high energy and power density are urgently demanded,which require suitable charge/discharge platform,fast charge-transfer kinetics,as well as optimal solid electrolyte interphase(SEI) layer of electrode materials.In this work,a high-performance lithium-ion battery(LIB) full cell was assembled by using commercial LiNi_(0.33)Co_(0.33)Mn_(0.33)O_2(NCM111) as the positive electrode and mixed Li_4 Li_5 O_(12)(LTO)/hard carbon(HC) as the negative electrode.It reveals that the component ratio between LTO and HC plays a critical role in manipulating the electric conductivity and the electro-reaction platform.The electrochemical test results show that when the content of HC is 10 wt%,the as-constructed full cell demonstrates the best electrochemical,with a maximum energy density of 149.2 Wh·kg~(-1) and a maximum power density of2195 W·kg~(-1) at 10 A·g~(-1)(30 C).This outperforms all the assembled systems within our work range and the state-ofthe-art literatures.The NCM//Li_4 Ti_5 O_(12)+10 wt% HC battery system also exhibits a good capacity retention after1000 cycles at the current density of 1 A·g~(-1).This work provides a new approach to enhance the full-cell performance by mixing electrode materials with different charge potentials and reaction kinetics.     

Ni-P-α-Al2O3纳米复合电镀工艺研究

采用复合电镀技术,在黄铜表面制备高硬度的Ni-P-α-Al2O3纳米复合镀层,研究了阴极电流密度、纳米α-Al2O3添加量、镀液pH值、镀液温度和电镀时间对镀层硬度的影响。结果表明:当镀液温度为45℃,阴极电流密度为4A/dm2,镀液pH值为4.0,电镀时间为40min,镀液中纳米α-Al2O3的质量浓度为10g/L时,所得镀层均匀、细致、平滑,经适当热处理后,显微硬度可达到1 332HV。     

AZ91D镁合金表面激光熔覆Al/Zr+B4C/Y2O3复合涂层组织与性能研究

目的提高AZ91D镁合金表面硬度,改善其耐腐蚀性。方法在AZ91D镁合金上涂覆Zr/B_4C/Y_2O_3混合粉末,之后使用Nd:YAG固体激光器进行激光熔覆。采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)对涂层的形貌和物相组成进行分析。利用显微硬度计以及电化学工作站对涂层的硬度和耐腐蚀性进行测定。结果涂层主要包含Zr C、Al3Zr和Al12Mg17等金属间化合物以及Al3Y等稀土化合物。添加0.8%Y_2O_3的涂层中有部分微小气孔,而添加1.6%Y_2O_3的涂层中气孔消失。析出相主要以颗粒状和棒状的形式存在,并且为了减小表面积,使得表面能降低,部分析出相聚集在一起长大。涂层硬度整体呈梯度分布,涂层外层的硬度最高(添加0.8%Y_2O_3的涂层为306.10HV,添加1.6%Y_2O_3的涂层为310.15HV)。添加0.8%Y_2O_3和1.6%Y_2O_3的涂层的平均硬度分别为291.613HV和294.495HV,相较于基体提高了4倍。添加0.8%Y_2O_3和1.6%Y_2O_3的涂层的自腐蚀电位分别为-1.269 V和-1.215 V,自腐蚀电流密度分别为7.655×10-5 A/cm2和2.048×10-6 A/cm2,相对于基体耐腐蚀性有了显著的提高。结论涂层中各种陶瓷相、金属间化合物和稀土化合物的存在使复合涂层的硬度、耐腐蚀性能均有了明显的提高。     

Thermal behavior analysis of a pouch type Li[Ni<Subscript>0.7</Subscript>Co<Subscript>0.15</Subscript>Mn<Subscript>0.15</Subscript>]O<Subscript>2</Subscript>-based lithium-ion battery

Since lithium-ion battery with high energy density is the key component for next-generation electrical vehicles,a full understanding of its thermal behaviors at different discharge rates is quite important for the design and thermal management of lithium-ion batteries（LIBs）pack/module.In this work,a 25 Ah pouch type Li[Ni_0.7Co_0.15Mn_0.15]O₂/graphite LIBs with specific energy of200 Wh kg^-1were designed to investigate their thermal behaviors,including temperature distribution,heat generation rate,heat capacity and heat transfer coefficient with environment.Results show that the temperature increment of the charged pouch batteries strongly depends on the discharge rate and depth of discharge.The heat generation rate is mainly influenced by the irreversible heat effect,while the reversible heat is important at all discharge rates and contributes much to the middle evolution of the temperature during discharge,especially at low rate.Subsequently,a prediction model with lumped parameters was used to estimate the temperature evolution at different discharge rates of LIBs.The predicted results match well with the experimental results at all discharge rates.Therefore,the thermal model is suitable to predict the average temperature for the large-scale batteries under normal operating conditions.