SnO2/Ni复合锂离子电池负极材料的制备及其电化学性能

采用机械球磨法将纳米SnO2和Ni粉末复合,作为锂离子电池负极材料。采用XRD、SEM、TEM和EDS分析球磨过程中材料结构和形貌的变化。对SnO2/Ni复合负极材料的首次库仑效率、循环稳定性及CV曲线等进行测试分析。结果表明:将复合粉末球磨适当时间后,SnO2和Ni可形成结合充分、颗粒尺寸细小、分布均匀的复合材料;SnO2和Ni的复合可有效提高SnO2的首次库仑效率和循环稳定性;SnO2/Ni复合负极材料的循环稳定性随球磨时间的延长而增加,但电极的首次库仑效率随球磨时间的延长呈先增加后下降的趋势;Ni的引入有效减小了SnO2在首次充放电循环过程中生成Li2O的不可逆反应程度,并在随后的循环过程中部分以Li-O化合物的形式进行可逆反应。     

Nano-SnO_2 Decorated Carbon Cloth as Flexible,Self-supporting and Additive-Free Anode for Sodium/Lithium-Ion Batteries

In this study,nano-sized SnO_2 decorated on carbon cloth(SnO_2/CC) is prepared through a simple and facile solid method.The nano-sized SnO_2 is uniformly distributed on the surface of carbon fibers in carbon cloth,providing sufficient free space to relieve volume expansion and reduce electrode pulverization during cycling.The as-prepared SnO_2/CC as a flexible,self-supporting and additive-free anode electrode for sodium-ion/lithium-ion batteries(SIBs/LIBs) can demonstrate outstanding electrochemical performance.SnO_2/CC after annealing at 350℃(SC-350) as an anode for SIBs can deliver a reversible capacity of 0.587 mA h cm~(-2) at the current density of 0.3 mA cm~(-2) after 100 cycles.In addition,when cycling at 1.5 mA cm~(-2),SC-350 can maintain 1.69 mA h cm~(-2) after 500 cycles when used as LIB anode.These results illustrate that the as-prepared SnO_2/CC can be a promising flexible anode material for flexible SIBs/LIBs and provide a simple and practical method for designing new flexible electrode materials.     

Synthesis and electrochemical properties of SnO2-CuO nanocomposite powders

1 Introduction Since YOSHIO et al[1] announced the commercia- lization of tin oxide as negative electrodes of 1ithium-ion batteries, the tin oxide anode has attracted much attention due to its high specific capacity, which is about twice that of graphite…     

TiO2-coated SnO2 hollow spheres as anode materials for lithium ion batteries

TiO2-coated SnO2(TCS) hollow spheres,which are new anode materials for lithium ion(Li-ion) batteries,were prepared and characterized with X-ray diffraction(XRD) ,scanning electron microscopy(SEM) ,transmission electron microscopy(TEM) ,cyclic voltammetry(CV) ,and galvanostatic charge/discharge tests.The results obtained from XRD,SEM,and TEM show that TiO2 can be uniformly coated on the surface of SnO2 hollow spheres with the assistance of anionic surfactant.The cyclic voltammograms indicate that both TiO2 a...     

Employment of encapsulated Si with mesoporous TiO2 layer as anode material for lithium secondary batteries

Silicon composite of nano-capsule type is newly applied as an active anode material for lithium ion batteries. TiO₂-encapsulated silicon powders were synthesized by a sol-gel reaction with titanium ethoxide. Silicon nanoparticles were successfully embedded into porous titanium oxide capsules that played as a buffer layer against drastic volume changes of silicon during the charge-discharge cycling, consequently leading to the retardation of the capacity fading of intrinsic silicon materials. The electrochemical and structural properties of silicon nanocomposites with different surface areas of encapsulating TiO₂ layer were characterized by X-ray diffraction(XRD), nitrogen gas adsorption analysis by the Brunauer-Emmett-Teller(BET) equation, transmission electron microscopy(TEM), and galvanostatic charge-discharge experiments.     

Preparation and magnetic properties of nanosized （La0. 47Gd0. 2 ） Sr0. 33 MnO3

1INTRODUCTION Themagneticpropertyandcrystalstructureof perovskite typelanthanummanganeseoxideswere firststudiedbyJonkerandVanSantenin1950[1].Thesematerialswereofconsiderableinterestinthe lastdecadeduetotheircolossalmagnetoresistance(CMR)effect[24].Recentlyaseriesofhole dopedperovskitemanganeseoxideswerereportedtodis playalargemagnetocaloriceffect(MCE)inthevic inityoftheferromagneticCurietemperature(Tc)[516],whichmaybeexploitedtobeappliedin magneticrefrigeratorandheatpumps[17].Idealmag…     

Synthesis and electrochemical performances of LiCoO2 recycled from the incisors bound of Li-ion batteries

A new LiCoO2 recovery technology for Li-ion batteries was studied in this paper. LiCoO2 was peeled from the Al foil with dimethyl acetamide (DMAC), and then polyvinylidene fluoride (PVDF) and carbon powders in the active material were eliminated by high tempera-1.00. The new LiCoO2 was obtained by calcining the mixture at 850℃ for 12 h in air. The structure and morphology of the recycled powders and resulting samples were studied by XRD and SEM techniques, respectively. The layered structure of LiCoO2 synthesized by adding Li2CO3 is the best, and it is found to have the best characteristics as a cathode material in terms of charge-discharge capacity and cycling mAh.g-1.     

改性钛酸锂负极材料的研究进展

尖晶石型钛酸锂作为锂离子电池负极材料,在充放电过程中其晶体结构不会发生改变,不可逆容量损失较小,被称为＂零应变＂材料。它具有循环寿命长、充电过程快、安全性高等特性,符合下一代锂离子电池的要求。本文综述了钛酸锂负极材料的研究近况,着重阐述了纳米化、引入导电碳、金属元素掺杂、阴离子掺杂以及复合改性等方法对钛酸锂进行改性,探究对其电性能的影响和以后的发展方向。     

Electrochemical properties of some cobalt antimonides as anode materi-als for lithium- ion batteries

Some cobalt antimonides have been prepared and studied as the candidate anode materials for lithium ion batter-ies. Reversible capacities of 424,423 and 546 mA·h·g-1 were measured at the first cycle for as-solidified CoSb2, CoSb3 and annealed CoSb3 respectively. A low lithium ions diffusion coefficient in the order of 10-16 m2·s-1 was estimated from the coulometric titration measurements in the annealed CoSb3 electrode. It was found that the electrochemical properties of fine powders are significantly better than coarse powders. However the SEM picture shows that the nano-sized CoSb3 powders gathered to larger granules, which worsens somewhat the capacity retention of the nano-sized materials, although the volume capacities of the annealed and ball milled CoSb3 remain near twice of that of graphite after 50 cycles.     

纳米级ITO粉体对烧结法制备靶材的影响

采用化学共沉淀法制备ITO前驱物,分别于600及1000℃下热处理前驱物,得到两种ITO粉体.粉体模压成型得到素坯,在400～1550℃内采用烧结法、氧气氛下烧结素坯制备出ITO靶材.对粉体及靶材进行表征和分析,研究了烧结过程中晶粒生长情况、靶材微结构与温度之间关系及靶材的失氧现象.得出600℃粉体为单相ITO固溶体、粒径为15 nm,1000℃粉体有少量SnO2析出、粒径为28 nm且其分散性和晶化程度优于600℃的粉体.两种粉体烧结制备靶材过程符合Coble固相烧结理论,1550℃时晶体出现类似二维成核生长方式的生长台阶.靶材密度随温度升高而增加,1550℃时随保温时间延长而增加.靶材致密化过程由团聚程度及团聚体大小决定,1000℃粉体制备的靶材密度高于600℃粉体所制靶材.两类靶材含氧量均低于理论值,1000℃粉体所制靶材含氧量高于600℃的含氧量.     

Pulsed laser deposited Sb2Se3 anode for lithium-ion batteries

Sb₂Se₃ thin film has been successfully fabricated by reactive pulsed laser deposition and was investigated for its electrochemistry with lithium for the first time. The reversible discharge capacities of Sb₂Se₃/Li cells cycled between 0.3 and 2.5 V were found in the range of 530.5–660.7 mAh g⁻¹ during the first 100 cycles. By using ex situ X-ray diffraction, transmission electron microscopy, and selected-area electron diffraction measurements, both classical alloying process and the selenylation/reduction of nanosized metallic antimony were proposed in the lithium electrochemical reaction of Sb₂Se₃. Sb₂Se₃ has high reversible capacity and good cycle performance, which makes it potential anode material for future lithium-ion batteries.     

快速充电锂离子电池LiEuTiO4负极材料研究进展

随着电动车产业的快速发展,锂离子电池的安全问题和快速充电问题越来越受到关注。石墨作为商业化已久的锂离电池负极材料,因其析锂平台近乎于零,而存在因负极析锂而短路的巨大安全隐患,因而不适用于快速充电的锂离子电池负极材料。具有层状钙钛矿结构LiEuTiO₄,其脱/嵌锂平台约为0.8V,实际比容量高于200 mAh/g,既可以避免析锂的发生, 又不会导致电池能量密度过低,且倍率性能良好,利用该材料有望发展出一种电动车用安全的快速充电动力电池。本工作总结了钛酸铕锂(LiEuTiO₄)负极材料的研究现状,包括分子结构、储锂机制、制备方法及亟待解决的问题,指出进一步的研究方向。     

Hierarchical CuO hollow microspheres: Controlled synthesis for enhanced lithium storage performance

In this work, hierarchical CuO hollow microspheres were hydrothermally prepared without use of any surfactants or templates. By controlling the formation reaction conditions and monitoring the relevant reaction processes using time-dependent experiments, it is demonstrated that hierarchical CuO microspheres with hollow interiors were formed through self-wrapping of a single layer of radically oriented CuO nanorods, and that hierarchical spheres could be tuned to show different morphologies and microstructures. As a consequence, the formation mechanism was proposed to proceed via a combined process of self-assembly and Ostwald's ripening. Further, these hollow microspheres were initiated as the anode material in lithium ion batteries, which showed excellent cycle performance and enhanced lithium storage capacity, most likely because of the synergetic effect of small diffusion lengths in building blocks of nanorods and proper void space that buffers the volume expansion. The strategy reported in this work is reproducible, which may help to significantly improve the electrochemical performance of transition metal oxide-based anode materials via designing the hollow structures necessary for developing lithium ion batteries and the relevant technologies.     

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.     

Performance of carbon-coated nano-ZnO prepared by carbonizing gel precursor as anodic material for secondary alkaline Zn batteries

Although carbon coating can improve the cycle life of anode for alkaline Zn batteries, the specific capacity reported is still lower compared with nanosized ZnO. Herein, carbon-coated nanosized ZnO (nano-ZnO@C) was synthesized by one-step heat treatment from a gel precursor in N₂. Commercial ZnO and homemade ZnO prepared similarly in air atmosphere were studied for comparison. Structure analysis displayed that both nano-ZnO@C and homemade ZnO had a porous hierarchical agglomerated architecture produced from primary nanoparticles with a diameter of approximately 100 nm as building blocks. Electrochemical performance measurements showed that nano-ZnO@C displayed the highest electrochemical activity, the lowest electrode resistance, the highest discharge capacity (622 mA·h/g), and the best cyclic stability. These properties were due to the combination of nanosized ZnO and the physical capping of carbon, which maintained the high utilization efficiency of nano-ZnO, and simultaneously prevented dendrite growth and densification of the anode.     

钛酸锂表面碳包覆改性研究进展

尖晶石结构的Li4Ti5O12由于电压平台平稳、循环寿命长、"零应变"和安全性高等优点,成为锂离子电池的热门负极材料。然而纯Li4Ti5O12本身为绝缘体,导电性很差,倍率性能不佳,这限制了它的实际应用。研究表明,对Li4Ti5O12表面进行碳包覆可以有效改善其电化学性能。结合最近国内外研究情况,综述了表面碳包覆对Li4Ti5O12负极材料改性的研究进展,分析了不同的碳包覆方法、碳层厚度、碳结构和碳含量对Li4Ti5O12/C复合材料电化学性能的影响,希望促进Li4Ti5O12/C复合电极材料在锂离子电池领域的应用。     

层次孔结构双功能碳负极材料的制备及性能

在500～900℃的活化温度下,以酚醛树脂为碳源,采用模板-物理活化联合法制备系列超级电容电池用层次孔结构双功能碳负极材料。借助扫描电镜、透射电镜及比表面积测试仪分析材料的物理结构,组装模拟电容器和对锂半电池,利用恒流充放电法及循环伏安法考察其电化学行为。结果表明:制备的层次孔结构碳材料具有较大的中微孔结构和局域石墨微晶结构;在LiPF6/EC+DMC和Et4NBF4/AN两种电解液中均表现出良好的电化学性能;其中以活化温度为600℃时制备的碳材料性能最优,其锂离子半电池可逆容量达到611.2 mA.h/g(0.2C),50次循环效率为74%,6C倍率下稳定可逆容量仍高达223 mA.h/g,模拟电容器比电容高达143 F/g(0.1 A/g),且倍率性能优异。     

Synthesis of nanosized tungsten carbide from phenol formaldehyde resin coated precursors

Nanosized tungsten carbide was synthesized from phenol formaldehyde resin (PF) coated tungsten precursors.The process has three steps in which nanosized tungsten particles were first coated with PF,then the precursors were carburized at 950℃,and finally the carburized powders were treated in flowing wet hydrogen atmosphere at 940℃ to remove the uncombined carbon.The obtained powders were characterizedusing X-ray diffraction analysis (XRD),field-emission scanning electron microscopy (FESEM),small angle X-ray scattering (SAXS),andcombustion-gas-volume method.The results indicated that single-phase WC could be synthesized using excessive PF as carburizer at a muchlower temperature compared with using mixed carbon black.After wet hydrogen treating,the mean size of the obtained WC particles was 94.5nm and the total carbon content was 6.18 wt.%.     

Hydrothermal Preparation of Homogeneous Cobalt Oxide Nanomaterials as Stable Anodes for Superior Lithium Ion Batteries

In this study,uniform Co_3O_4 nanoparticles are prepared via a simple and facile hydrothermal synthesis without calcination treatment.When the Co_3O_4 nanomaterials are investigated as anodes for lithium ion batteries,a good electrochemical property is achieved.Particularly,the reversible capacity of the as-synthesized Co_3O_4 nanoparticle has a significant growth from383 mAh g~(-1) of the initial cycle to 471 mAh g~(-1) of the 300 th cycle at 2 A g~(-1).Moreover,when it recovers to 50 mA g~(-1) after different current densities,a superior reversible capacity of 695 mAh g~(-1) can be reached.Such favorable electrochemical properties will make the as-obtained Co_3O_4 have a good application prospect as anode material for lithium ion batteries.     

Synthesis and electrochemical performances of spherical LiFePO4 cathode materials for Li-ion batteries

Spherical LiFePO4 and LiFePO4/C composite powders for lithium ion batteries were synthesized by a novel processing route of co-precipitation and subsequent calcinations in a nitrogen and hydrogen atmosphere. The precursors of LiFePO4, LiFePO4/C composite and the resultant products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and the electrochemical performances were investigated by galvanostatic charge and discharge tests. The precursors composed of amorphous Fe3(PO4)2·xH2O and crystalline Li3PO4 obtained in the co-precipitation processing have a sphere-like morphology. The spherical LiFePO4 derived from the calcinations of the precursor at 700 ℃ for 10 h in a reduction atmosphere shows a discharge capacity of 119 mAh·g -1 at the C/10 rate, while the LiFePO4/C composite with 10wt.% carbon addition exhibits a discharge capacity of 140 mAh·g -1.The electrochemical performances indicate that the LiFePO4/C composite has a higher specific capacity and a more stable cycling performance than the bare olivine LiFePO4 due to the carbon addition enhancing the electronic conductivity.