环己苯对锰酸锂离子电池过充性能的影响

研究在电解液中添加环己基苯(CHB)对锰酸锂锂离子电池的防过充性能的影响,考察CHB的加入对电池循环性能及容量等的影响.并采用红外光谱和扫描电镜等方法分析正极产物及正极表面形貌,以确定添加剂的防过充机理.结果表明:在电解液中添加2%的CHB可明显提高锰酸锂电池的耐过充性能,在3C/10 v极端条件下,电池不起火不爆炸,循环100周后,容量保持率为93.22%,CHB的防过充机理为阻断机理.     

锂离子电池的现状与发展

<正> 锂离子电池由日本索尼公司于1990年最先开发成功。它是把锂离子嵌入到碳中形成负极,取代传统锂池的金属锂或锂合金负极。负极材料主要是石油焦碳和石墨。正极材料是Lix-CoO2.LixNiO2和Li1+xMn2O4。电解质为L1AsF6+PC（丙烯碳酸）,LiAsF6+PC+EC（乙烯碳酸）及L1PF6+EC+DMC（二甲基碳酸）。该种电池也分为非再充和再充电池。非再充电池属于超薄型电池。它呈汽状,厚约0.2mm,故系世界上最薄的电池。电     

聚丙烯酸对钒电池正极热稳定性和电化学性能的影响（英文）

通过原位热稳定性试验、紫外-可见光谱、拉曼光谱、X射线光电子能谱(XPS)、循环伏安法和充/放电试验,研究了聚丙烯酸(PAA)对全钒氧化还原流电池(VRFB)正极电解液的热稳定性和电化学性能的影响。结果表明,PAA添加剂可以提高V(V)电解液的热稳定性。在室温条件下,少量的PAA添加剂对电解液电化学性能影响不大,仅能轻微地提高正极电解液的电化学性能和VRFB的能量效率。此外,以PAA添加量为3%的正极电解液组装电池,该电池在50℃时表现出良好的充/放电循环性能,其充电容量保持率高于没有添加PAA的电池。     

宽温域锂离子电池功能电解液的研究进展

分析锂离子电池在低温工作条件下的性能劣化机理,阐述溶剂物理性质对电解液低温性能的影响规律,总结目前通过低黏度及低熔点的溶剂组分、低阻抗的成膜添加剂以及新型锂盐来改善电池低温性能的研究工作。同时,探讨锂离子电池在高温工作条件下容量衰减机制,综述目前改善锂离子电池高温性能的主要方法,包括采用高温成膜添加剂、耐高温锂盐以及锂盐稳定剂。在此基础上指出目前宽温域锂离子电池发展面临的主要挑战,展望锂离子宽温域电解液的发展趋势。     

碳酸亚乙烯酯添加剂对LiFeP04／石墨电池高温循环性能的影响

研究成膜添加剂对材料结构稳定性及LiFePO4/石墨电池高温循环性能的影响。分别测试添加和未添加碳酸亚乙烯酯（VC）的18650电池的高温循环性能,并通过充放电测试、交流阻抗、扫描电镜、X射线能量色散光谱以及拉曼光谱等方法研究 VC 对电池正、负材料结构的影响。结果表明：VC 添加剂在提高石墨结构稳定性的同时显著抑制LiFePO4材料中的溶铁行为;此外,VC添加剂阻止电解液在负极表面还原分解及负极表面SEI膜的增厚,也阻止电解液在LiFePO4电极表面的分解;含有VC添加剂的电解液可以有效改善LiFePO4/石墨电池在高温下的循环稳定性。     

碳酸亚乙烯酯添加剂对LiFePO_4/石墨电池高温循环性能的影响（英文）

研究成膜添加剂对材料结构稳定性及LiFePO4/石墨电池高温循环性能的影响。分别测试添加和未添加碳酸亚乙烯酯(VC)的18650电池的高温循环性能,并通过充放电测试、交流阻抗、扫描电镜、X射线能量色散光谱以及拉曼光谱等方法研究VC对电池正、负材料结构的影响。结果表明:VC添加剂在提高石墨结构稳定性的同时显著抑制LiFePO4材料中的溶铁行为;此外,VC添加剂阻止电解液在负极表面还原分解及负极表面SEI膜的增厚,也阻止电解液在LiFePO4电极表面的分解;含有VC添加剂的电解液可以有效改善LiFePO4/石墨电池在高温下的循环稳定性。     

Li3+xV2(PO4)3的合成及电化学性能研究

通过碳热还原法合成了化学计量比的Li3V2(PO4)3和富锂的锂离子电池正极材料Li3+xV2(PO4)3(x=0.02,0.04,0.05,0.06).利用XRD、SEM和电化学测试对Li3+xV2(PO4)3进行研究表明:所合成的试样均为单斜晶系结构,无杂相存在;SEM测试发现,掺锂可以明显改善Li3V2(PO4)3一次颗粒表面的结构和形貌;电化学性能测试表明,随着掺锂量的提高,试样的循环性能变好.通过研究发现,Li3.04V2(PO4)3具有较高的初始容量和良好的循环性能.     

尖晶石LiMn2O4和LiCoO2与电解液的相容性

研究锂离子电池正极活性材料尖晶石LiMn2O4和LiCoO2与6种电解液充、放电时的相容性。用X射线衍射检测自制的LiCoO2试样和尖晶石LiMn2O4试样的结构；用粉末微电极循环伏安法测定6种电解液在导电剂乙炔黑表面的氧化电位；将制得的尖晶石LiMn2O4试样和LiCoO2试样在上述电解液中进行恒电流充放电实验。结果表明：充电至高电位3．3～4．3V（vs Li／Li^＋）时，如果正极活性材料表面与电解液发生不可逆反应并在其上覆盖一薄层电子不可导的钝化膜，则将导致活性材料的充、放电效率降低，放电容量减少，即正极活性材料与电解液的相容性差；反之，则相容性好；尖晶石LiMn2O4与上述6种电解液的相容性都很好，普适性强；LiCoO2与上述6种电解液的相容性差别较大，呈选择性。     

添加剂四氟硼酸四乙基铵对石墨负极界面性能的影响

采用恒流充放电、循环伏安(CV)和交流阻抗(EIS)测试方法研究四氟硼酸四乙基铵(Et4NBF4)作为锂离子电池电解液添加剂对石墨负极材料界面性质的影响,通过傅里叶变换红外光谱(FTIR)对固体电解质界面膜(SEI)的成分变化进行分析。结果表明:添加剂Et4NBF4参与了SEI膜的形成,提高了人造石墨(AG)/Li半电池充电容量和后续的循环效率,但是降低了首次充放电效率;首次放电过程中1.0～0.5 V是SEI膜形成和生长的电位区间,而0.5 V以下SEI膜进行不断的修复;添加少量Et4NBF4降低了SEI膜阻抗,提高了电解液与石墨负极的相容性。     

聚丙烯酸对钒电池正极热稳定性和电化学性能影响的研究。

通过原位热稳定性、紫外-可见光谱、拉曼光谱、X射线光电子能谱(XPS)、循环伏安法和充放电方法,研究了聚丙烯酸(PAA)对全钒氧化还原流电池(VRFB)正极电解液的热稳定性和电化学性能的影响。结果表明,PAA添加剂可以提高V(V)电解液的热稳定性。在室温条件下,少量的PAA添加剂能轻微的提高正极电解液的电化学性和VRFB的能量效率。此外,以PAA添加量为3%的正极电解液组装电池,该电池在50 ℃ 时表现出良好的充放电循环性能,其充电容量保持率高于没有添加PAA的电池。     

Non-flammable electrolytes based on trimethyl phosphate solvent for lithium-ion batteries

1 INTRODUCTIONLithium-ion rechargeable batteries containelectrolyte solutions composed of Li salts and or-ganic solvents , typically organic carbonates . Al-most all these solutions are flammable and may beignited when hot solvents expelled from the cellscomes in contact with oxygen under abusive condi-tions such as overcharge[1 3]. In extreme case ,abused lithium-ion batteries have been reported tocombust and explode[4 6].Some separators have been used to exhibitshutdown performance to p…     

Thermal stability of LiPF6/EC+DMC+EMC electrolyte for lithium ion batteries

The thermal stability of lithium-ion battery electrolyte could substantially affect the safety of lithium-ion battery. In order to disclose the thermal stability of 1.0 mol·L-1 LiPF6/ethylene carbonate (EC)+dimethyl carbonate (DMC)+ethylmethyl carbonate (EMC) electrolyte, a micro calorimeter C80 micro calorimeter was used in this paper. The electrolyte samples were heated in argon atmosphere, and the heat flow and pressure performances were detected. It is found that LiPF6 influences the thermal behavior remarkably, with more heat generation and lower onset temperature. LiPF6/EC shows an exothermic peak at 212 ℃ with a heat of reaction -355.4J·g-1.DMC based LiPF6 solution shows two endothermic peak temperatures at 68.5 and 187 ℃ in argon filled vessel at elevated temperature. EMC based LiPF 6 solution shows two endothermic peak temperatures at 191 and 258 ℃ in argon filled vessel.1.0mol·L-1LiPF6/EC+DMC+ EMC electrolyte shows an endothermic and exothermic process one after the other at elevated temperature. By comparing with the thermal behavior of single solvent based LiPF6 solution, it can be speculated that LiPF6 may react with EC, DMC and EMC separately in 1.0 mol·L-1LiPF6/EC+DMC+EMC electrolyte, but the exothermic peak is lower than that of 1.0 mol·L-1LiPF6/EC solution. Furthermore, The 1.0 mol·L-1 LiPF6 /EC+DMC+EMC electrolyte decomposition reaction order was calculated based on the pressure data, its value is n =1.83, and the pressure rate constants kp=6.49×10-2k Pa·-0.83·min-1 .     

Optimization of iron sulfides usage in electrolytic composites with graphites for lithium-ion batteries

Iron sulfides were codeposited with different nature graphite for the increase of the utilization efficacy in their electrochemical reaction with lithium. Synthesized iron sulfide-graphite composites have been investigated in the galvanostatic mode using a model lithium accumulator filled with an electrolyte solution of 1 M LiClO₄ in EC, DMC. It was established that the codeposition of iron sulfides with synthetic graphite stabilizes the discharge capacity of electrolytic iron sulfides at their long cycling. Synthesized iron sulfide composites with synthetic graphite represent prospective negative electrodes for thin-layer lithium-ion batteries. The natural graphite manufactured by the Superior Graphite Company (purified surface coated natural graphite, ABG 1005, ABG 1010, formula BT SLC 1520 P) displays an unfit stabilization ability of the iron sulfide discharge capacity.     

Enhancing cycle stability of Li metal anode by using polymer separators coated with Ti-containing solid electrolytes

The employment of lithium metal anode in rechargeable lithium batteries has been hindered by the safety concerns which are associated with the uncontrolled lithium dendrite growth and the unceasing side reactions with liquid electrolytes.In this work,we report that the use of Ti-containing solid electrolyte-coated separators can greatly enhance the cycle performances of lithium metal anode in cells using liquid electrolytes.The detailed morphologic studies indicate that more uniform lithium deposition is achieved in cells using Ti-containing solid electrolyte-coated separators than that using Al_2 O_3-coated separators,which is likely due to the modified anode and electrolyte interfacial properties induced by the reactive nature of Ti-containing solid electrolytes with metallic lithium.This work demonstrates an effective strategy to enhance the homogeneity of lithium deposition,which leads to the stable cycling of lithium metal anode in rechargeable lithium-ion batteries.     

Ultrathin Al_2O_3-coated reduced graphene oxide membrane for stable lithium metal anode

Lithium(Li) metal has been considered as the most attractive anode materials for Li-ion batteries(LIBs)due to its high theoretic specific capacity. The formation of unstable solid electrolyte interphase(SEI) and dendritic Li on the metal anode, however, hindered its practical application. Herein, to address the issues, a Li-free electrode with ultrathin Al_2O_3 coated on reduced graphene oxide(rGO) membrane that covers a Cu foil current collector was developed. The composite electrode exhibits excellent interfacial protection of lithium metal deposited between Cu foil and rGO electrochemically. Firstly, it affords good Li~+ permeability from the electrolyte. Secondly, the ultrathin Al_2O_3 has sufficient mechanical strength to inhibit the penetration of Li dendrite. Li metal was observed uniformly deposited between rGO membrane and Cu collector, and stable cycle performance of Li plating/stripping with Coulombic efficiency of ~91.75% at the 100 th cycle is achieved in organic carbonate electrolyte without any additives.     

Investigation of electrolytic tin-nickel alloys as anode materials for lithium-ion batteries

Electrolytic deposits of tin-nickel alloys as anodes for lithium-ion batteries were investigated by potentiodynamic and galvanostatic cycling methods in solutions of ethylene carbonate, dimethyl carbonate, and LiClO₄ (1 mol/L). It has been shown that the deposits of tin-nickel alloys obtained from alkaline tartrate-trilonate electrolytes in the first cycles are characterized by a high specific capacity of up to 700 mA h/g, which decreases to 500 mA h/g during the cycling. The tin-nickel alloys obtained are able to ensure high charge-discharge current densities without mechanical destruction.     

Electrochemical performance of tris(2-chloroethyl) phosphate as a flame-retarding additive for lithium-ion batteries

We studied tris(2-chloroethyl) phosphate (TCEP) as a potential flame-retarding additive and its effect on the electrochemical cell performance of lithium-ion battery electrolytes. The electrochemical cell performance of additive-containing electrolytes in combination with a cell comprised of a LiCoO₂ cathode and a mesocarbon microbeads anode was tested in coin cells. The cyclic voltammetry results show that the oxidation potential of TCEP-containing electrolyte is about 5.1 V (vs. Li/Li⁺). A cell with TCEP has a better electrochemical cell performance than a cell without TCEP in an initial charge and discharge test. In a cycling test, a cell containing a TCEP-containing electrolyte has a greater discharge capacity and better capacity retention than a TCEP-free electrolyte after cycling. The results confirm the promising potential of TCEP as a flame-retarding additive and as a means of improving the electrochemical cell performance of lithium-ion batteries.     

Electrochemical properties of rechargeable organic radical battery with PTMA cathode

The electrochemical properties of the organic radical battery (ORB) having a lithium metal anode and a cathode consisting of a nitroxide radical polymer poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) with 1M LiPF₆ as an electrolyte in ethylene carbonate (EC)/dimethyl carbonate (DMC) have been evaluated at room temperature. The cell, with a thin cathode of 17 μm thickness incorporating 40 wt.% of PTMA, exhibited the full theoretical specific capacity at current densities up to 10 C (∼1 mA/cm²). However, a decrease in the specific capacity and an increase in the ohmic resistance were observed at higher current densities. The cell performance was good even on repeated charge-discharge cycles as an excess of 85 % retention of the initial discharge capacity was observed. This was true even after 400 cycles. However, a gradual decrease in capacity, an increase in charge-discharge voltage separation, and an electrode/electrolyte interfacial resistance have been observed after a large number of cycles. The examination of the scanning electron micrographs of the cathode material revealed that prolonged cycling resulted in the agglomeration of PTMA particles. These in turn increased the resistance and decreased the capacity of the cell.     

Electrochemical Study of Monoclinic Li3V2(PO4)3 in the Voltage Range of 1.5~3.0 V

采用液相法合成了Li3V2(PO4)3(空间群P21/n)电活性材料。用XRD和恒流充放电对样品的微观结构和电化学性能进行了表征。结果表明,在1.5~4.3V电压范围内,样品在平均电压为1.81和3.77V时均发生了可逆的锂嵌入反应;锂嵌出和嵌入过程中均出现一系列复杂的相变。在1.5~3.0V电压范围内,以C/5倍率循环50周后,样品的容量衰减极小,表明锂脱嵌反应具有优良的循环稳定性。因此,Li3V2(PO4)3可以同时作为正极和负极而组成对称电池。另外,1.5~4.3V电压范围内进行的嵌锂反应可以充当一种内置的过充电安全阀。     

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。