Triethoxysilane with oligo（ethylene oxide） substituent as film forming additive for graphite anode

{3-[2-(2-methoxyethoxy) ethoxy]-propyl} triethoxysilane (TESM2) was synthesized and used as an electrolyte additive to improve the performances of lithium-ion batteries (LIBs). The electrochemical properties of the electrolyte (1 mol/L lithium hexafluorophosphate (LiPF₆)/ethylene carbonate (EC):diethylene carbonate (DEC):dimethyl carbonate (DMC), 1:1:1) with different contents of TESM2 were characterized by ionic conductivity measurement, galvanostatic charge/discharge test of graphite/Li half cells, and electrochemical impedance spectroscopy. Both the cycling performances and C-rate capabilities of graphite/Li half cells were significantly improved with an optimized content of 15% TESM2 in the electrolyte. The graphite/Li half cell delivered a very high specific capacity of 370 mAh/g at 0.2C rate without any capacity loss for 60 cycles, and retained a capacity of 292 mAh/g at 2C rate. The solid electrolyte interphase (SEI) film on the surface of the graphite anode was investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), indicating that TESM2 was effectively involved in the formation of SEI film on the surface of graphite.     

六方LiMnBO3/C复合物的合成及电化学性能

采用流变相法方法,成功地合成了六方晶型的LiMnBO3/C复合材料.用XRD、TG、SEM等技术对材料的结构和形貌进行表征,并对其电化学性能进行了测试,结果表明：在电压范围为1.0～4.6 V,电流密度为10 mA/g的充放电条件下,煅烧温度为800℃时,合成的样品首次放电比容量达到了139 mAh/g,而煅烧温度为800℃时,合成的样品首次放电比容量只有105mAh/g.其电化学性能有了明显的改善,具有较高的可逆比容量和优良的循环性能.     

Electrochemical properties of CoFe<Subscript>3</Subscript>Sb<Subscript>12</Subscript> as potential anode material for lithium-ion batteries

A skutterudite-related antimonide, CoFe₃Sb₁₂, was prepared with vacuum melting. XRD analysis showed the material contained Sb, FeSb₂, CoSb₂ and CoSb₃ phases. The electrochemical properties of the ball-milled CoFe₃Sb₁₂−10 wt% graphite composite were studied using pure lithium as the reference electrode. A maximal lithium inserting capacity of about 860 mAh/g was obtained in the first cycle. The reversible capacity of the material was about 560 mAh/g in the first cycle and decreased toca. 320 mAh/g and 250 mAh/g after 10 and 20 cycles respectively.Ex-situ XRD analyses showed that the antimonides in the pristine material were decomposed after the first discharge and that antimony was the active element for lithium to insert into the host material. Project supported by the National Natural Foundation of China (No. 59771032) and the RFDP of the Education Ministry of China (No. 20010335045)     

Electrochemical properties of CoFe3Sb12 as potential anode material for lithium-ion batteries

A skutterudite-related antimonide, CoFe3Sb12, was prepared with vacuum melting. XRD analysis showed the material contained Sb, FeSb2, CoSb2 and CoSb3 phases. The electrochemical properties of the ball-milled CoFe3Sb12-10 wt% graphite composite were studied using pure lithium as the reference electrode. A maximal lithium inserting capacity of about 860 mAh/g was obtained in the first cycle. The reversible capacity of the material was about 560 mAh/g in the first cycle and decreased to ca. 320 mAh/g and 250 mAh/g after 10 and 20 cycles respectively. Ex-situ XRD analyses showed that the antimonides in the pristine material were decomposed after the first discharge and that antimony was the active element for lithium to insert into the host material.     

Electrochemical properties of CoFe_3Sb_(12) as potential anode material for lithium-ion batteries

INTRODUCTIONBinaryskutteruditeshavecubicIm35()hTstructureandthechemicalformofAB3,whereArepresentsametalatomandBrepresentsapnico-genatom.Thereareeightformulaunitspercubicunitcell,inwhichthereareadditionallytwostructuralvoidswiththeradiivariedfrom1.63?forCoP3to2.040?forIrSb3.Thevoidislargeenoughforanalkalineearthorrareearthatomtoinsertintoitandtoformternarycompoundscalledfilledskutterudites.Inthesecompounds,theinsertinglooselyboundatomscanmoveorbouncearoundinsidethevoidsduetotherelative…     

纳米Co3O4/石墨烯复合材料制备及电化学性能研究

Co3O4纳米复合材料是钠离子电池重要的材料.本文采用溶剂热渗碳、水热的方法在清洗后的宏孔导电网络表面覆盖了一层Co3O4/纳米石墨烯复合材料.纳米Co3O4层由直径为200 nm的薄片构成.电化学测试表明,作为钠离子电池负极材料Co3O4/nanographene/MECN初始容量达到了815 mAh/g,可逆容量300 mAh/g,该结构的Co3O4纳米复合材料为下一代钠离子电池结构设计提供了新思路.     

锂离子电池SiO/C复合负极材料的制备及性能研究

以正硅酸乙酯和蔗糖为原料,采用液相法制备了SiO/C复合负极材料。通过XRD、SEM以及恒流充放电测试等方法研究了煅烧温度、溶液pH值对SiO/C材料的相组成、颗粒形貌及电化学性能的影响。结果表明,煅烧温度为800℃、pH=6时制备的SiO/C负极材料具有高的可逆比容量(～500mAh/g)及优良的循环性能。这主要是由于煅烧温度为800℃时材料中无定形碳的碳化程度较高,pH=6时可形成较小的SiO核心颗粒。     

溶胶凝胶法制LiFePO4作为锂电池正极材料的研究

采用固相法和溶胶凝胶法（sol-gel）成功地制备出了LiFePO4．并利用X射线衍射、扫描电镜以及电化学测试等手段，系统地研究了合成条件和方法对材料的结构和电化学性能的影响．研究表明，使用sol—gel方法和固相法，制备出单一相的LiFePO4，其比容量分别为130mAh／g和80mAh／g．采用sol—gel方法制备的LiFePO4作为电池正极材料具有高的比容量和优良的电化学性能．     

Facile Fabrication of Fe_3O_4@TiO_2@C Yolk–Shell Spheres as Anode Material for Lithium Ion Batteries

Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis,high specific capacity,and environmental-friendly.In this paper,Fe_3O_4@TiO_2@C yolk-shell(Y-S) spheres,used as anode material for lithium ion batteries,were successfully fabricated by Stober method.XRD patterns reveal that Fe_3O_4@TiO_2@C Y-S spheres possess a good crystallinity.But the diffraction peaks' intensity of Fe_3O_4 crystals in the composites is much weaker than that of bare Fe_3O_4 spheres,indicating that the outer anatase TiO_2@C layer can cover up the diffraction peaks of inner Fe_3O_4 spheres.The yolk-shell structure of Fe_3O_4@TiO_2@C spheres is further characterized by TEM,HAADFSTEM,and EDS mapping.The yolk-shell structure is good for improving the cycling stability of the inner Fe_3O_4 spheres during lithium ions insertion-extraction processes.When tested at 200 mA/g,the Fe_3O_4@TiO_2@C Y-S spheres can provide a stable discharge capacity of 450 mAh/g over 100 cycles,which is much better than that of bare Fe_3O_4 spheres and TiO_2@C spheres.Furthermore,cyclic voltammetry curves show that the composites have a good cycling stability compared to bare Fe_3O_4 spheres.     

合成温度对磷酸亚铁锂电化学性能的影响

橄榄石型结构的LiFePO4是一种新的锂离子电池正极材料。从提高材料的稳定性及降低锂离子电池的生产成本两方面出发,研究了用高温固相法合成橄榄石LiFePO4时,温度对其结构及电化学性能的影响。在氮气保护下,采用高温固相反应法在350oC预分解5h,650℃焙烧24h制备的LiFePO4具有较好的晶形、放电容量和循环性能,其首次放电容量达到92mAh／g,40次循环后放电容量达到77mAh／g,容量衰减16％。     

锂离子电池材料Li_(1+x)Zn_xMn_(2-x)O_4电化学性质研究

采用溶胶-凝胶法合成了Zn2+取代的锂离子电池正极材料Li1+xZnxMn2-xO4。结构研究结果表明,用这种方法可以在比固相反应低得多的温度下得到单相的尖晶石且制得的材料粒度均匀,粒径大多在150nm左右。半电池循环测试结果表明,起始组成为x=0.06的样品性能最佳,其与锂片组成的半电池在3.0V—4.6V间,以0.10mA/cm2的电流密度进行充放电的首次充、放电容量分别为131.4mAh/g和129.2mAh/g,经35次循环后容量仍保持在100mAh/g。     

Hierarchical NiCo LDH–rGO/Ni Foam Composite as Electrode Material for High-Performance Supercapacitors

In this study, a bulk composite material symbolized as NiCo LDH-rGO/Ni F was developed by a solvothermal process for the first time. This material was fabricated through simultaneous growth of nickel-cobalt layered double hydroxide(NiCo LDH) and reduced graphene oxide(rGO) on nickel foam. This bulk composite can be used directly as a binder-free electrode for supercapacitors(SCs). The physicochemical properties of this composite were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The electrochemical properties of the composite were measured by the cyclic voltammetry and galvanostatic charge-discharge. The results show that this composite had a hierarchical structure and exhibited a significantly enhanced specific capacitance of up to 3383 F/g at 1 A/g. The asymmetric SC using this composite as a positive electrode had a high energy density of 40.54 Wh/kg at the power density of 206.5 W/kg and good cycling stability. Owing to the synergies between the metal oxides and the rGO, the preparation method of in situ growth and its hierarchical structure, this bulk composite displayed excellent electrochemical performance and had a promising application as an efficient electrode for high-performance SCs.     

Preparation of natural α-tocopherol from non-α-tocopherols

Non-α-tocopherols are hydroxymethylated and hydrogenated to produce α-tocopherol in one pot process bysimultaneously reacting with paraformaldehyde and hydrogen in the presence of catalysts of benzenesulfonic acid and 5%Pd/C in an autoclave. Effects of various operation conditions have been studied. The preferable reaction conditions are: temperature 180 ℃ to 200 ℃, pressure 5.0 MPa, acid concentration 0.5 g/100 ml ethanol, mass ratio of Pd/C to tocopherols 7.1 g/100 g, and reaction time 5.0 h. A product with α-tocopherol content of 80% was obtained by using a raw material with a total tocopherols content of 80.54%. The conversion of non-α-tocopherols is almost 100%, and the mole yield ofα-tocopherol is more than 90%.     

立方形锰氧化物的制备及其电容特性研究

目的 :制备立方形锰氧化物高电容超级电容器材料。方法:采用水热结合热分解的方法,制备结构均一的锰氧化物的立方体结构;利用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)等方法对样品进行了微观表征,使用自制的三电极体系对电极材料进行了循环伏安(CV)、充放电性能和循环稳定性研究。结果:检测结果显示,所制备的立方体结构是由一个个约为10 nm的小颗粒自组装形成的,颗粒之间具有丰富的微孔结构。电化学测试显示在电流密度为1 A/g下,担载量为2 mg/cm2的条件下,电极材料的放电比容量高达318 F/g,其作为正极材料具有比较好的电容特性。结论:此方法制备过程简单,容易工业化生产,该立方形的锰氧化物较适合作为超级电容器的正极材料。     

Effects of surface modification by Ni, Ti and B on electrochemical properties of Mg1.8Cu0.2Ni hydrogen storage alloy

Amorphous alloy Mg1.8Cu0.2Ni was successfully prepared by mechanical alloying (MA) and a series of (n?x)Nix(Ti?B) composites were synthesized by MA. The electrochemical properties of Mg1.8Cu0.2Ni coated by Ni, Ti and B were studied by cyclic charge-discharge, linear polarization curve, and hydrogen diffusion coefficient experiments. Experimental results indicate that Mg1.8Cu0.2Ni-[0.9Ni0.6(Ti?B)] composite which was MA 30 h exhibited the best performance and its initial discharge capacity arrived to 714.1 mAh/g. After 30 cycles the discharge capacity was above 530 mAh/g, which was much higher than that of Mg1.8Cu0.2Ni. And after 100 cycles it holded still 442.1 mAh/g. On all accounts, after modification by Ni, Ti and B, the initial discharge capacity and high-rate discharge ability of the electrode were evidently increased. At the same time, the cycle performance was also improved significantly.     

Density Functional Theory Calculations for the Evaluation of FePS_3 as a Promising Anode for Mg Ion Batteries

FePS_3, a classical 2D layered material with transition metal phosphorous trichalcogenides, was investigated as an anode material for Mg ion batteries. We used density functional theory to calculate the Mg storage properties of FePS_3, such as Mg adsorption energy, theoretical specifi c capacity, average voltage, diff usion energy barriers, volume change, and electronic conductivity. The theoretical specifi c capacity of the FePS_3 monolayer is 585.6 mA h/g with a relatively low average voltage of 0.483 V(vs. Mg/Mg~(2+)), which is favorable to a high energy density. The slight change in volume and good electronic conductivity of bulk FePS 3 are benefi cial to electrode stability during cycling.     

LiFePO4在季铵盐离子液体电解液中的电化学性能

应用循环伏安和恒电流充放电等方法研究了橄榄石型LiFePO4正极材料在季铵盐离子液体电解液中的电化学嵌脱锂性质。研究表明：电极的扫描速率和工作温度均可影响LiFePO4正极材料的充放电容量和循环性能。     

LiFePO4在季铵盐离子液体电解液中的电化学性能

应用循环伏安和恒电流充放电等方法研究了橄榄石型LiFePO4正极材料在季铵盐离子液体电解液中的电化学嵌脱锂性质。研究表明:电极的扫描速率和工作温度均可影响LiFePO4正极材料的充放电容量和循环性能。     

棒状钒酸锂的制备与电化学性能研究

采用水热法制备了锂离子电池正极材料LiV3O8,通过X射线衍射(XRD)、红外光谱(FT-IR)和扫描电子显微镜(SEM)表征研究了样品的结构和形貌特征;通过恒流充放电技术测试了样品的电化学性质.结果表明,水热法制备的LiV3O8样品由棒状颗粒组成,粒径约0.5μm,棒长约1-3μm.首次放电容量为276mAh/g.所制备LiV3O8材料具有较高的初始放电比容量和良好的循环性能.     

锂离子电池负极材料Sb2O3-x/rGO的氧缺陷构建及其电化学性能研究

成功制备了氧缺陷型Sb2O3-x/rGO复合材料.与纯Sb2O3材料相比,Sb2O3-x/rGO复合材料颗粒尺寸大大减小,导电性能得到提高,作为锂离子电池的负极材料,具有更高的可逆能力、更好的循环稳定性和良好的倍率性能.在电流密度为100 mAh·g^-1的情况下,Sb2O3-x/rGO复合材料的初始放电容量可达1336.6 mAh·g^-1.即使经过50次充放电循环后,其充放电容量依然可以保持在405.8 mAh·g^-1.