Al2O3包覆LiNi0.03Co0.05Mn1.92O4正极材料的制备及其电化学性能

以Al(NO3)3?9H2O为包覆原料,通过燃烧法制备得到LiNi0.03Co0.05Mn1.92O4@Al2O3正极材料。通过X射线衍射(XRD),场发射扫描电子显微镜(FESEM)和透射电镜(TEM)等表征手段对材料的结构和形貌进行分析,并通过恒电流充放电、循环伏安(CV)、交流阻抗(EIS)等测试分析材料的电化学性能。结果表明,Al2O3包覆没有改变LiNi0.03Co0.05Mn1.92O4的尖晶石型结构,包覆层厚度约10.6nm。LiNi0.03Co0.05Mn1.92O4@Al2O3正极材料电化学性能得到了明显改善,1 C和10 C倍率下初始放电比容量分别为119.9 mAh?g-1和106.3 mAh?g-1,充放电循环500次后容量保持率分别为88.4%和78.2%,而未包覆的LiNi0.03Co0.05Mn1.92O4在1 C和10 C倍率下初始放电比容量分别为121.2 mAh?g-1和104.0 mAh?g-1,500次循环后容量保持率分别为84.1%和67.6%。LiNi0.03Co0.05Mn1.92O4@Al2O3活化能为32.92 kJ?mol-1,而未包覆材料的活化能为36.24 kJ?mol-1,包覆有效降低了材料Li+扩散所需克服的能垒,提高了材料的电化学性能。     

Synthesis and performance of Li3Ve(PO4)3/C composites as cathode materials

Carbon-coated Li3V2(PO4)3 cathode materials for lithium-ion batteries were prepared by a carbon-thermal reduction (CTR) method using sucrose as carbon source.The Li3V2(PO4)3/C composite cathode materials were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and electrochemical measurement.The results show that the Li3V2(PO4)3 samples synthesized using sucrose as carbon source have the same monoclinic structure as the Li3V2(PO4)3 sample synthesized using acetylene black as carbon Source.SEM image exhibits that the particle size is about 1 μm together with homogenous distribution.Electrochemical test shows that the initial discharge capacity of Li3V2(PO4)3 powders is 122 mAh·g-1 at the rate of 0.2C,and the capacity retains 111 mAh·g-1 after 50 cycles.     

Effect of LiTFSI and LiFSI on Cycling Performance of Lithium Metal Batteries Using Thermoplastic Polyurethane/Halloysite Nanotubes Solid Electrolyte

All-solid-state lithium batteries(ASSLB) are promising candidates for next-generation energy storage devices.Nevertheless,the large-scale commercial application of high energy density AS S LB with the polymer electrolyte still faces challenges.In this study,a thin solid polymer composite electrolyte(SPCE) is prepared through a facile and cost-effective strategy with an infiltration of thermoplastic polyurethane(TPU),lithium salt(LiTFSI or LiFSI),and halloysite nanotubes(HNTs) in a porous framework of polyethylene separator(PE)(TPU-HNTs-LiTFSI-PE or TPU-HNTs-LiFSI-PE).The composition,electrochemical performance,and especially the effect of anions(TFSI~-and FSI~-) on cycling performance are investigated.The results reveal that the flexible TPU-HNTs-LiTFSI-PE and TPU-HNTs-LiFSI-PE with a thickness of 34 μm exhibit wide electrochemical windows of 4.9 and 5.1 V(vs.Li+/Li) at 60℃,respectively.Reduction in FSI~-tends to form more LiF and sulfur compounds at the interface between TPU-HNTs-LiFSI-PE and Li metal anode,thus enhancing the interfacial stability.As a result,cell composed of TPU-HNTs-LiFSI-PE exhibits a smaller increase in interfacial resistance of solid electrolyte interphase(SEI) with a distinct decrease in charge-transfer resistance during cycling.Li|Li symmetric cell with TPU-HNTs-LiFSI-PE could keep its stable overpotential profile for nearly 1300 h with a low hysteresis of approximately39 mV at a current density of 0.1 mA cm~(-2),while a sudden voltage rise with internal cell impedance-surge signals was observed within 600 h for cell composed of TPU-HNTs-LiTFSI-PE.The initial capacities of NCMITPU-HNTs-LiTFSIPEILi and NCMITPU-HNTs-LiFSI-PEILi cells were 149 and 114 mAh g~(-1),with capacity retention rates of 83.52% and89.99% after 300 cycles at 0.5 C,respectively.This study provides a valuable guideline for designing flexible SPCE,which shows great application prospect in the practice of ASSLB.     

Synthesis and electrochemical properties of sol-gel derived LiMn2O4cathode for lithium-ion batteries

Spinel LiMn2O4 has been considered to be the most promising alternative cathode material for the new generation of lithium-ion batteries in terms of its low cost, non-toxicity and easy manufacture. The spinel lithium manganese mixed oxides were prepared from lithium nitrate, manganese nitrate and citric acid by asol-gel method and were characterized by thermogravimetric analysis, X-ray diffraction, cyclic voltammetry and constant current charging-discharging technique. The different sintering temperatures for different time have strong influence on the structure, initial discharge capacity and cycling performance of the lithium manganese oxide. It shows that the lithium manganese oxides sintered at 700 ℃ for 10 h have a single spinel structure and better electrochemical properties. The initial discharging capacity can be up to 125.9 mAh·g-1 , even after six cycles, it still retains 109.1 mAh·g-1 .     

Electrochemical and Pseudocapacitive Analysis of Rod-Like MoO2@MoSe2@NC Heterostructures for High-Performance Lithium Ion Batteries

A micro-scale rod-like heterostructure derived from molybdenum-based metal organic framework (Mo-MOF) has been successfully prepared via subsequent annealing treatment,which assembled from N-doped carbon encapsulated MoSe2 nanosheets grown on the surface of MoO2 microrod (named as MoO2@MoSe2@NC).For this novel heterostructure,the MoO2 nanoparticles assembled into rod core not only serve as supporting substrate for facilitating the fast kinetics of Li+ cations inside the electrode but also protect the MoSe2 structure from restacking in the charge/discharge process.Moreover,the outer-layered MoSe2 nanosheets enable the fast lithium ion movement owing to its large interlayer spacing.Moreover,this unique rod-like core-shell structure composite could further effectively alleviate the structural strains caused by large volume expansion during charge/discharge process,thus leading to stable electrochemical performance when evaluated as anode material for lithium ion batteries.Electrochemical testing exhibits that the MoO2@MoSe2@NC heterostructure presents highly reversible capacity of 468 mAh g-1 at 0.5 A g-1 and superior rate capability (318 mAh g-1 even at 5.0 A g-1),which is attributed to the synergistic effect of N-doped carbon encapsulated MoSe2 nanosheets and MoO2 nanoparticles.     

PEO对固态锂电池正极/电解质界面的改性

在固态锂电池正极/氧化物电解质界面处引入聚氧化乙烯(PEO)缓冲层以改善固体接触。首先,用热压烧结法制备了密度为5.25 g·cm-3、锂离子电导率为8.33×10-4S·cm-4的Li6.4La3Zr1.4Ta0.6O12(LLZTO)固体电解质。其次,配制了PEO-LiTFSI-LLZTO缓冲层和LiFePO4复合正极浆料,用匀胶机旋涂法将PEO缓冲层和复合正极浆料依次涂覆在电解质表面,加热加压后显著改善界面接触,测得60℃下正极界面电阻值为509Ω·cm2。测试对称电池充/放电曲线证明界面稳定性良好,电池首次循环放电容量145.8 mAh·g-1,库伦效率大于97%。     

Preparation of low cobalt high rate discharge hydrogen storage alloy MlNi_(3.85)Co_(0.45) Mn_(0.4)Al_(0.3)X_(0.1)(X=Mg,Si,Sn)

1　INTRODUCTIONInrecentyears,Ni/MHbatterythatisanewgenerationbatterywithhighenergydensitywasrapidlydevelopedafterwardsNi/Cdbattery .WiththeincreasinglymatureofNi/MHbatteryproductiontechnique,itbeginstojointhefieldofhighpowerandgreatcapacitycell,andbecomesgraduallythemostpromisinggreendynamiccellthatwasappliedtoelectromotivemotor .Thehydrogenstoragealloy ,asthekeymaterialofNi/MHdynamiccell,mustbecharacterizedbyitshighspecialcapacity ,highvolt ageplatform ,goodcatalyzeactivity ,longcycl…     

SnO_2 quantum dots modified N-doped carbon as high-performance anode for lithium ion batteries by enhanced pseudocapacitance

SnO_2 is considered to be a promising candidate as anode material for lithium ion batteries,due to its high theoretical specific capacity(1494 mAh·g~(-1)).Nevertheless,SnO_2-based anodes suffer from poor electronic conductivity and serious volume variation(300%) during lithiation/delithiation process,leading to fast capacity fading.To solve these problems,SnO_2 quantum dots modified N-doped carbon spheres(SnO_2 QDs@N-C) are fabricated by facile hydrolysis process of SnCl_2,accompanied with the polymerization of polypyrrole(PPy),followed by a calcination method.When used as anodes for lithium ion batteries,SnO_2 QDs@N-C exhibits high discharge capacity,superior rate properties as well as good cyclability.The carbon matrix completely encapsulates the SnO_2 quantum dots,preventing the aggregation and volume change during cycling.Furthermore,the high N content produces abundant defects in carbon matrix.It is worth noting that SnO_2 QDs@N-C shows excellent capacitive contribution properties,which may be due to the ultra-small size of SnO_2 and high conductivity of the carbon matrix.     

锂硫电池正极材料Al-ABTC/RGO@S的制备及电化学性能

通过溶剂热法制备了一种高比表面积的铝基金属有机框架（metal organic frameworks,MOFs）材料Al-ABTC。然后通过静电吸附法将Al-ABTC与氧化石墨烯（GO）复合,并载硫得到Al-ABTC/RGO@S复合材料用于锂硫电池。采用 X 射线衍射(XRD)分析了Al-ABTC的晶体结构,采用扫描电镜(SEM)对Al-ABTC、Al-ABTC/GO和Al-ABTC/RGO@S的八面体形貌进行表征,用恒流充放电测试材料的电化学性能。结果表明,Al-ABTC/RGO@S复合电极在0.2 C电流密度下的首次放电容量达到1345.3 mAh g-1,经过200次的循环以后还能达到406.4 mAh g-1的比容量,其平均库伦效率为99.1%。此外电池即使在2 C下,首次放电比容量高达714.7 mAh g-1,经过300次循环以后容量保持在331 mAh g-1,表现出良好的长循环性能。     

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。     

Facile Preparation of NiO@graphene Nanocomposite with Superior Performances as Anode for Li-ion Batteries

Transition metal oxides gain considerable research attentions as potential anode materials for lithium ion batteries, but their applications are hindered due to their poor electronic conductivity, weak cycle stability and drastic volume change. Here, a NiO@graphene composite with a unique 3D conductive network structure is prepared through a simple strategy. When applied as anode material for Li-ion batteries, at 50 mA g^-1, the NiO@graphene displays a high reversible capacity of 1366 mAh g^-1 and a stable cyclability of 205 mAh g^-1 after 500 cycles. Even at a high rate of 10 A g^-1, it displays a favorable reversible capacity of 711 mAh g^-1. Remarkably, when it recovers back to 0.05 A g^-1, a reversible capacity of 1741 mAh g^-1 is achieved. Thus, the NiO@graphene composite with 3D structure shows good application prospects as an alternative anode for advanced lithium ion batteries.     

Highly Efficient Na+ Storage in Uniform Thorn Ball-Like a-MnSe/C Nanospheres

Because of its high theoretical capacity,MnSe has been identified as a promising candidate as the anode material for sodiumion batteries.However,its fast capacity deterioration due to the huge volume change during the intercalation/deintercalation of sodium ions severely hinders its practical application.Moreover,the sodium storage mechanism of MnSe is still under discussion and requires in-depth investigations.Herein,the unique thorn ball-like α-MnSe/C nanospheres have been prepared using manganese-containing metal organic framework (Mn-MOF) as a precursor followed by in situ gas-phase selenization at an elevated temperature.When serving as the anode material for sodium-ion battery,the as-prepared α-MnSe/C exhibits enhanced sodium storage capabilities of 416 and 405 mAh g-1 at 0.2 and 0.5 A g-1 after 100 cycles,respectively.It also shows a superior capacity retention of 275 mA h g-1 at 10 A g-1 after 2000 cycles,and a rate performance of 279 mA h g-1 at 20 A g-1.Such sodium storage properties could be attributed to the unique structure offering a highly efficient Na+ diffusion kinetics with a diffusion coefficient between 1 × 10-11 and 3 × 10-10 cm2 s-1.The density functional theory calculation indicates that the fast Na+ diffusion mainly takes place on the (100) plane of MnSe along a V-shaped path because of a relatively low diffusion energy barrier of 0.15 eV.     

Electrochemical performances of hydrogen storage alloys treated using a new milling technique

A new self-made additive of amidocyanogen-acetic salt was used in wet bail-grind technique (WBGT) for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was investigated in detail. It was found that the prepared electrode had perfect electrochemical performances, such as rapid activation, high capability, high-rate discharge (HRD) ability, and good stability. The first discharge capacitance at 0.2 C (throughout this study, n C rate means that the rated capacity of a hydrogen storage alloy (full capacity) is charged or discharged completely in 1/n h) reached 278mAh.g-1 and the discharge capacitance reached the maximum of 322mAh·g-1 only after two charge-discharge cycles. For the dry method, wet method, and WBGT, the high rate discharge (HRD) values (C5C/C0.2C ratio) were approximately 0.59, 0.76, and 0.83, respectively. The stable discharge capacity at 3 C increased from 275mAh·g-1 (dry method) to 295mAh·g-1 (WBGT).     

Mechanism of lithium insertion into NiSi2 anode material for lithium ion batteries

As a promising high capacity anode material for lithium ion batteries, the lithium insertion performance and possible insertion mechanism of binary alloy of NiSi2 were discussed. The initial lithium insertion of crystal NiSi2 can reach up to 600 mAh·g-1 , but large irreversible capacity occurrs simultaneously for serious structure transformation and the irreversible phase forms. XRD and XPS were employed to detect the crystal structure and composition changes produced by lithium insertion. The lithium insertion-extraction behavior of NiSi2 electrode is similar to that of silicon after the first discharge. The structure stability seems related to the non-stoichimometric Ni-Si compound formed by lithium insertion into NiSi2.     

A novel Zn-PANI dry rechargeable battery

Conducting polyaniline (PANI) powder was well mixed with graphite and acetylene black to obtain the optimum conductivity and porosity. The mixed powder was compressed into a pellet for cathode. Zinc powder was mixed with some metal powder, and compressed into a pellet used as the anode. The electrolyte comprised ZnCl2, NH4Cl, Triton-X100 and PVA at pH3. The battery has an open-circuit voltage of 1.44 V. The battery underwent charge-discharge cycle with a constant current density of 3 mA·cm-2 , within the voltage range of 0.40-1.68 V. It is found that the capacity of the battery is related to the charge-discharge cycles, the maximum capacity is 67.9 mAh·g-1 , and Coulombic efficiency is between 95% and 100%. The battery stability was also investigated after 78 d of standing without use. It is found that the battery experiences a self-discharge of less than 0.29% per day.     

锂离子电池正极材料LiCoO2-LiFePO4的性能

研究用LiCoO2-LiFePO4作正极的锂离子电池的电化学性能和安全性能。结果表明:电池在1、3和5C倍率的放电容量分别为347.7、327.2和322.5 mA.h,5C条件下的放电容量为1C放电容量的92.8%。在25℃、1C条件下循环150次的容量保持率为100%;在?10℃、1C条件下的放电容量为256.5 mA.h,是25℃、1C放电容量的74.8%。电池具有很好的耐过充性能,在3C、10 V条件下进行过充电,电池不漏液、起火或爆炸。短路时电池的表面温度低于LiCoO2电池的表面温度。     

Synthesis and electrochemical properties of Th-doped LiMn2O4 powders for lithium-ion batteries

To improve the cycle performance of eco-friendly and cost-effective spinel LiMN2O4 as the Li secondary batteries, the Th-doped LiThxMn1-xO4 spinel powers were synthesized by solid-state method. The starting materials, Li2CO3,MnO2 and Th(NO3)4·4H2O, were mixed uniformly using a traditional ball milling, which resulted in a uniform particle size distribution in the mixed powers. Tests of X-ray diffraction, SEM, impedance spectra and charge-discharge were carried out for LiThxMn1-xO4 cathode materials. Results show that the synthesized LiTh0.01Mn1.99O4 material exhibits standard spinel structure, regular particle morphology and excellent property of charge-discharge for big current. The capacity retention of the material modified by doping Th is more than 85.1% of the first discharge specific capacity of 111.5 mAh·g -1 after 20 cycles at the current rate 1C, while the pristine LiMN2O4 is only 57% of the first discharge specific capacity of 110.2 mAh·g-1 after the same cycles at the same current rate.     

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.     

Ni^2+掺杂对LiFePO_4正极材料电化学性能的影响

采用固相反应法在惰性气氛下合成了橄榄石型LiFePO4及其Ni^2＋掺杂正极材料,采用XRD,SEM和充放电等方法对目标材料进行了表征。XRD分析表明,掺杂少量Ni^2＋后的LiFePO4晶体结构并未发生变化;SEM观察发现,掺杂后,样品的粒径变小;充放电测试得出,比未掺杂的LiFePO4具有更好的电化学性能,首次放电比容量达145mAh·g^-1,高于纯的LiFePO4正极材料的容量90mAh·g^-1,经100次循环后掺杂Ni^2＋的LiFePO4和LiFePO4样品的容量保有率分别为91％和53％。     

磷酸铁锂/石墨烯复合材料的低温微波水热法制备及性能

采用喷雾干燥结合低温微波水热法制备了石墨烯/LiFePO₄复合正极材料,利用SEM、XRD、DLS等对其微观形貌、结构、粒度分布进行了表征,并利用恒流充放电、CV、EIS等测试研究了复合正极材料的电化学性能和电极动力学过程。结果表明,与未包覆的样品相比,石墨烯包覆的LiFePO₄具有优异的倍率性能(5C放电比容量为125.4 mAh?g_-1)和循环稳定性(1C条件下100次充放电后容量保持率在95%左右)。包覆石墨烯后LiFePO₄正极材料的电荷迁移电阻减小,电化学可逆性增强,从而提高了材料的倍率性能。本文提供了一条提高磷酸铁锂正极材料电化学性能的简便途径,具有良好的应用前景。