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。     

A novel organosilicon-based ionic plastic crystal as solid-state electrolyte for lithium-ion batteries

A novel organosilicon-based ionic plastic crystal, N,N,N,-diethylmethyl-N-[(trimethylsilyl)methyl]ammonium bistrifluoromethane sulfonimide ([DTMA][TFSI]) was designed and synthesized as solid-state electrolyte for lithium-ion batteries. The chemical structure and the physical and electrochemical properties were characterized in detail. The ionic conductivity of [DTMA][TFSI] was improved significantly by doping with lithium oxalyldifluoroborate (LiODFB) and propylene carbonate (PC). An optimized plastic crystal composite ([DTMA][TFSI]:LiODFB:PC=8:1:1 in molar ratio) as a solid-state electrolyte exhibited a decent cycling stability in LiFePO₄/Li half-cell, with a specific discharge capacity of 144 mA·h/g and capacity retention of 94% after 50 cycles at C/20.     

VC—Li2 CO3电解液添加剂对锂离子电池TMP基阻燃电解液电化学性能的影响

以磷酸三甲酯（TMP）为阻燃添加剂制备了4种锂离子电池电解液1mol·L^-1LiPF6（1-y％）（ECn-DMC1.0-EMC1.0）-y％TMP（（n,y）=（1,44％）,（1．5,39％）,（2,35％）,（1．0,0％））。考察了碳酸亚乙烯酯——碳酸锂添加剂对采用磷酸三甲酯阻燃添加剂的电解液的石墨负极与LiCoO2正极电化学性能的影响。结果表明,制备的1mol·L^-1 LiPF6 61％（EC1.5-DMC1．0-EMC10）-39％TMP-4％VC-0．05mol·L^-1 Li2CO3电解液具有较好的综合电化学性能,VCLi2CO3添加剂有效抑制了TMP在碳电极的分解和共嵌入行为。采用这种电解液制备的Li／graphite电池的首次放电比容量为336．5mAh·g^-1、以0．1C倍率循环20次的放电比容量为334．5mAh·g^-1,制备的Li／LiCoO2电池的首次放电比容量为145．2mAh·g^-1、以0．1C倍率循环20次的放电比容量为136．5mAh·g^-1。     

Hydrogen Bonding-Assisted Synthesis of Silica/Oxidized Mesocarbon Microbeads Encapsulated in Amorphous Carbon as Stable Anode for Optimized/Enhanced Lithium Storage

The practical application of silica-based composites as an alternative to commercial graphite anode materials is hampered by their large volumetric expansion,poor conductivity,and low Coulombic efficiency.In this work,a novel silica/oxidized mesocarbon microbead/amorphous carbon(SiO_2/O'MCMB/C) hierarchical structure in which SiO_2 is sandwiched between spherical graphite and amorphous carbon shell was succes sfully fabricated through hydrogen bonding-assisted self-assembly and post-carbon coating method.The obtained three-layer hierarchical structure effectively accommodates the volumetric expansion of SiO_2 and significantly enhances the electronic conductivity of composite materials.Moreover,the outer layer of amorphous carbon effectively increases the diffusion rate of lithium ions and promotes the formation of stable SEI film.As a result,the SiO_2/O'MCMB/C composite exhibits superior electrochemical performance with a reversible capacity of 459.5 mA h/g in the first cycle,and the corresponding Coulombic efficiency is 62.8%.After 300 cycles,the capacity climbs to around 600 mA h/g.This synthetic route provides an efficient method for preparing SiO_2 supported on graphite with excellent electrochemical performance,which is likely to promote its commercial applications.     

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…     

锂离子电池石墨烯负极材料的制备与电化学性能

以天然石墨为原料,采用Hummers法制备氧化石墨烯,在硼氢化钠为还原剂制备石墨烯材料。采用XRD、电化学阻抗谱技术（EIS）、电化学充放电测试和红外分析等方法表征了石墨烯的结构和电化学性能。结果表明,石墨烯首次放电容量为866．4mAhg^-1,首次充电容量为305．2mAhg^-1,库仑效率为35．2％。     

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.     

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．