纳米Co-Sn合金负极材料的制备和电化学性能

用水热法于150oC合成了CoSn2纳米合金负极材料。水热反应前还原剂NaBH4的加入速度和水热反应后的热处理均会影响产物的相组成和CoSn2合金组分的颗粒大小,从而影响电极的电化学性能。较大的CoSn2合金颗粒有利于降低电极的首次不可逆容量损失和提高循环稳定性。电极的循环性能还与循环电流密度有关,较小的初始电流密度能够充分激活活性颗粒的嵌锂通道,并在颗粒表面形成较好的固体电解质膜(SEI膜),有利于改善电极的循环性能。     

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.     

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.     

Preparation of layered oxide Li（Co1/aNi1/3Mn1/3）O2 via the sol-gel process

To obtain homogenous layered oxide Li(Co1/3Ni1/3Ni1/3Mn1/3)O2 as a lithium insertion positive electrode material,the sol-gel process using citric acid as a chelating agent was applied.The material Li(Co1/3,Ni1/3Mn1/3)O2 was synthesized at different calcination temperatures.XRD experiment indicated that the hyered Li(Co1/3Ni1/3Mn1/3)O2material could he synthesized at a lower temperature of 800℃,and the oxidation state of Co,Ni,and Mn in the cathode confirmed by XPS were 3, 2,and 4,respectively.SEM observations showed that the synthesized material could form homogenous particle morphology with the particle size of about 200nm In spite of different calcination temperatures,the charge-discharge curves of all the samples for the initial cycle were similar,and the cathode synthesized at 900℃ showed a small irreversible capacity loss of 11.24% and a high discharge capacity of 212.2 mAh.g-1 in the voltage range of 2.9-4.6 V.     

碳热还原合成SnSb合金负极材料的电化学性能

以锡和锑的氧化物为原料，采用碳热还原法，制备了锂离子电池用微米级球形SnSb合金负极材料。材料表现出较低的首次不可逆容量和较好的循环性能。首次不可逆比容量为160mAh／g，可逆比容量达650mAh／g。其较低的比表面积是其较低的首次不可逆容量的主要原因，而颗粒的多晶特性则有利于电极材料循环稳定性的提高。同时采用循环伏安和交流阻抗测试研究了SnSb合金的电极反应过程。     

Zr-Ti系贮氢合金表面改性研究

采用化学镀镍、镀钴、机械混合以及球磨几种方法对Zr-Ti系贮氢合金进行了表面改性。XRD结果表明，随着镀镍量的增加，合金越趋向微晶化；球磨时间越长，合金的衍射峰更加弥散化，充放电试验结果表明，当镀镍量为15％(质量分数，下同)时，贮氢合金在60mA.g^-1的电流密度下初始容量比未处理的合金高出130mAh．g^-1，经过6次～8次循环完全活化，最大放电容量可达400mAh．g^-1，随着镀镍量的增加，抗自放电能力增加；当镀钴量为5％时，贮氢合金在60mA．g^-1的电流密度下初始容量比未处理的合金高出40mAh．g^-1，经过7次～9次循环完全活化，最大放电容量可达390mAh．g^-1，但随着镀钴量的增加，初始容量上升较快，但放电容量在减少；而机械混合仅提高初始容量，对最大放电容量没有改善；球磨不仅改善贮氢合金的活化性能，并且其最大放电容量可达450mAh．g^-1。     

Effects of rapid quenching on structure and cycle stability of La-Mg-Ni-Co type hydrogen storage alloy

In order to improve the cycle stability of La-Mg-Ni-Co type alloy electrode, rapid quenching technology was employed. The effects of rapid quenching on the microstructure and cycle stability of the alloy were investigated. The obtained results show that the La2Mg(Ni0.85Co0.15)9M0.1 (M=B, Cr) alloy electrodes are composed of (La, Mg)Ni3 phase, LaNi5 phase and a small amount of the LaNi2 phase. A trace of the Ni2B phase exists in the as-cast MB alloy, and the Ni2B phase in the alloy nearly disappears after rapid quenching. Rapid quenching technology can slightly improve the cycling life of the alloy. When the quenching rate increases from 0 m·s -1 (As-cast is defined as quenching rate of 0 m·s-1 ) to 30 m·s -1 , the cycle lives of the MB, M Cr alloys enhance from 86 and 87 cycles to 106 and 119 cycles, respectively. On the other hand, the average capacity decay rates of the MB, M Cr alloys decrease from 1.7172 and 1.7178 mAh·g-1·cycle-1 to 1.5751 and 1.3060 mAh·g-1·cycle-1 after 86 charge-discharges cycling, respectively.     

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.     

Effect of Fe2P in LiFePO4/Fe2P composite on electrochemical properties synthesized by MA and control of heat condition

In order to control the size and distribution of the high conductive Fe2P in LiFePO4/Fe2P composite, two different cooling rates (Fast: 15 ℃·min-1, Slow: 2 ℃·min-1) were employed after mechanical alloying.The discharge capacity of the fast cooled was 83 mAh·g-1 and the slow cooled 121 mAh·g-1.The particle size of the synthesized powder was examined by transmission electron microscopy and distribution of Fe2P was characterized using scanning electron microscopy (SEM).In addition, two-step heat treatment was carried out for better distribution of Fe2P.X-ray diffraction (XRD) and Rietveld refinement reveal that LiFePO4/Fe2P composite consists of 95.77% LiFePO4 and 4.33% of Fe2P.     

Cu对Sn-Co/C复合材料结构和电化学性能的影响

分别以单质Cu粉和CuCO3.Cu(OH)2为Cu源,采用固相烧结法制备锂离子电池Sn-Co-Cu/C复合材料,利用SEM、XRD和电池程控测试仪研究Cu对材料结构和电化学性能的影响。结果表明:Sn-Co/C复合材料由CoSn相和微量CoSn2组成,添加Cu粉或CuCO3.Cu(OH)2的Sn-Co-Cu/C均由大量CoSn、α-Co3Sn2和少量CoSn2组成;添加的Cu固溶于Sn-Co合金,使颗粒细化,同时比表面积也增大。添加Cu粉和CuCO3.Cu(OH)2的Sn-Co-Cu/C的首次充电、放电容量分别为467、319 mA.h/g和489、326 mA.h/g,经过40次循环后容量保持率分别为83.4%和86.8%;添加Cu导致多相的形成以及颗粒的细化,增加了Li+的扩散通道和增强了材料的结构稳定性,从而显著改善了材料的电化学性能。     

非晶态纳米氢氧化镍电极材料物理特性与电化学性能

采用快速冷冻沉淀法制备出了非晶态纳米氢氧化镍。对制得材料样品进行了XRD，SEM，TEM，DSC和比表面积与孔径分析，将其制成MH-Ni电池正极材料进行充放电性能测试。结果表明：材料粉体为非品态，颗粒粒度为纳米级，类似球形。非晶纳米Ni（OH）2的热分解温度286．4℃低于常规球形Ni（OH）2的热分解温度333.8℃，同时具有较大得比表面积和孔径，分别为76．2089m^2·g^-1和37．7nm。与普通β-Ni（OH）2相比较，非晶态纳米氢氧化镍电极充电电压低，放电电压平台时间长，且高达1．258V，放电比容量为349．85mAh／g，具有较好的循环性能，20次循环后其容量衰减仅为1．28％。     

Preparation of Li[Ni1/3Co1/3Mn1/3]O2 powders for cathode material in secondary battery by solid-state method

Employing Li2CO3, NiO, Co3O4, and MnCO3 powders as starting materials, Li[Ni1/3Co1/3Mn1/3]O2 was synthesized by solid-state reaction method.Various grinding aids were applied during milling in order to optimize the synthesis process.After successive heat treatments at 650 and 950 ℃, the prepared powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy, and transmission electron microscopy.The powders prepared by adding salt (NaCl) as grinding aid exhibit a clear R3m layer structure.The powders by other grinding aids like heptane show some impurity peaks in the XRD pattern.The former powders show a uniform particle size distribution of less than 1 μm average size while the latter shows a wide distribution ranging from 1 to 10 μm.Energy dispersive X-ray (EDX) analysiss show that the ratio of Ni, Co, and Mn content in the powder is approximately 1/3, 1/3, and 1/3, respecively.The EDX data indicate no incorporation of sodium or chlorine into the powders.Charge-discharge tests gave an initial discharge capacity of 160 mAh·g-1 for the powders with NaCl addition while 70 mAh·g-1 for the powders with heptane.     

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。     

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…     

Synthesis and physicochemical properties of LiLa0.01Mnt.99O3.99F0.01 cathode materials for lithium ion batteries

Spinel lithium manganese oxide cathode materials were synthesized using the ultrasonic-assisted sol-gel method.The synthesized samples were investigated by differential thermal analysis (DTA) and thermogravimetry (TG),powder X-ray diffraction (XRD),scanning electron microscopy (SEM),cyclic voltammetry (CV),and the charge-discharge test.TG-DTA shows that significant mass loss occurs in two temperature regions during the synthesis of LiLa0.01Mn1.99O3.99F0.01.XRD data indicate that all samples exhibit the same pure spinel phase,and LiLa0.01Mn1.99O3.99F0.01 and LiLa0.01Mn1.99O4 samples have a better crystallinity than LiMn2O4. SEM images indicate that LiLa0.01Mn1.99O3.99F0.01 has a slightly smaller particle size and a more regular morphology structure with narrow size distribution.The charge-discharge test reveals that the initial capacities of LiMn2O4,LiLa0.01Mn1.99O4,and LiLa0.01Mn1.99O3.99F0.01 are 130,123,and 126 mAh·g-1,respectively,and the capacity retention rates of the initial value,after 50 cycles,are 84.8%,92.3%,and 92.1%,respectively.The electrode coulomb efficiency and CV reveal that the electrode synthesized by the ultrasonic-assistexi sol-gel (UASG) method has a better reversibility than the electrode synthesized by the sol-gel method.     

CoSb3-graphite composite anode material for lithium ion batteries

The CoSb3-graphite composite was prepared by ball-milling. The electrochemical performance of the composite material was evaluated using the lithium ion model cell Li/ LiPF6 (EC DMC) / CoSb3C4. It was found that the CoSb3C4 composite shows higher reversible capacity than the pure CoSb3 alloy, and its firSt reversible (Li-ions removal) capacity reaches 721 mA.h.g^-1, which exceeds the theoretical capacity (550 mA.h.g^-1) of CoSb3C4.     

Electrochemical hydrogen storage properties of La0.95Mg2.05Ni9 alloy prepared by mechanical alloying

1　INTRODUCTIONTheMg basedhydrogenstoragealloysastheac tivematerialsofmetalhydrideelectrodeshaveattract edattentionbecauseofhighertheoreticalcapacitiesforhydrogenabsorption/desorption ,andthelowerpricecomparedwiththeotherhydrides[17] .Recent ly ,thecharge dischargepropertiesofMg basedalloysatroomtemperaturehavebeengreatlyimprovedbysomeresearchers[813] .Inparticular ,theMg Ni REsystemalloyisoneofthemost promisinghydrides[14 16 ] .Tanakaetal[15] reportedthatthenanocrystallineMg Ni RE(R…     

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 .     

PVdF-HFP-Based Gel Polymer Electrolyte with Semi-Interpenetrating Networks For Dendrite-Free Lithium Metal Battery

The safety issues and lower energy density of the lithium metal batteries are the two main challenges that hinder their applications in the fields of electric vehicles and portable devices.In this work,the semi-interpenetrated polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP)-based gel polymer electrolyte was synthesized through UV-curing method by employing the ethoxylated trimethylolpropane triacrylate (ETPTA) monomer.The semi-interpenetrating networks formed by polymerization of ETPTA and the high liquid absorption rate of the PVdF-HFP impart the as-prepared electrolyte with a high room temperature ionic conductivity of 3.17 × 10-3 s cm-1 and a high mechanical strength of 3.46 MPa.LiFePO4 was selected as cathode materials,and the active material loading of the cathode is about 4.2 mg cm-2.The electrolyte shows superior long-term cycling properties (127 mAh g-1 after 200 cycles at 0.5 C),excellent rate performance (113 mAh g-1 at 1 C,80 mAh g-1 at 2 C,and the discharge capacity of 135 mAh g-1 can be restored when the rate goes back to 0.1 C) as well as good ability to inhibit the growth of lithium dendrite (about 150 h).The facile synthesis strategy and great electrochemical performance of the electrolyte make it a potential candidate for lithium metal batteries.