层状LiMnO2正极材料由于其高理论比容量(285 mAh g-1)、高能量密度、低成本引起了学者们的广泛注意。为了能制备出稳定的层状LiMnO2正极材料,并获得优良的循环性能,本文通过改进的高温固相法制备出了稳定的层状LiMnO2正极材料采用了XRD...层状LiMnO2正极材料由于其高理论比容量(285 mAh g-1)、高能量密度、低成本引起了学者们的广泛注意。为了能制备出稳定的层状LiMnO2正极材料,并获得优良的循环性能,本文通过改进的高温固相法制备出了稳定的层状LiMnO2正极材料采用了XRD和电化学测试等手段对材料的晶体结构组成,电化学性能进行了测试表征,研究结果如下:本文成功合成了具有层状结构的LiMnO2正极材料。对其不同温度下合成的材料进行XRD测试以及电化学性能测试,发现不同温度下制备的LiMnO2正极材料均出现一定程度的团聚,且颗粒粒径分布不均匀;在0.1C放电倍率下,750℃下制备得到的LiMnO2正极材料具有最高的放电比容量(131 mAh g-1),经过60次循环后,材料放电比容量为100 mAh g-1,容量保持率为76.3%。展开更多
Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel struct...Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4 and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2+ or Co3+ in LiMnO2 led to the structure of LiMnO2 transiting to Qα-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2 was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature.展开更多
Composite materials composed of LiMnO2, a typical electrode material for lithium ion battery, and a chiral cyanide-bridged Ni（Ⅱ）-Fe（Ⅲ） coordination polymer [NiL2][Fe（CN）6]·4H2O （Ni-Fe, H-form） （L = （1...Composite materials composed of LiMnO2, a typical electrode material for lithium ion battery, and a chiral cyanide-bridged Ni（Ⅱ）-Fe（Ⅲ） coordination polymer [NiL2][Fe（CN）6]·4H2O （Ni-Fe, H-form） （L = （1R,2R）-（-）-1,2-cyclohexane-diamine） or its deuterium isomer, [NiL2][Fe（CN）6]·4D2O （Ni-Fe, D-form） have been prepared by the various ratios （w/w） of Ni-Fe：LiMnO2 = 10：0 （pure Ni-Fe）, 9：1, 8：2, 7：3, 6：4, 5：5, 4：6, 3：7, 2：8, 1：9 and 0：10 （pure LiMnO2）. Gradual shift of IR （infrared） spectra by changing the ratios and losing difference between H-form and D-form of Ni-Fe due to isotope effects revealed adsorption of Ni-Fe onto LiMnO2 to form composite materials. Formation of composite materials of Ni-Fe and LiMnO2 could be also proved losing ferromagnetic behavior of LiMnO2 on increasing of the ratios of Ni-Fe in each composite. In contrast to smoothly positive thermal expansion of pure LiMnO2 along the crystallographic b axis, variable temperature powder XRD （X-ray diffraction） patterns at 100-300 K of the composite materials exhibited thermally-accessible lattice distortion along the b axis with different ratios. It is also proved deviation of ideal linear correlation of an evaluation function, In K = a/T ＋ b （where, K = （d（T） - d（0））/d（T）, d（T） denotes nλ/（sin 2θ） at T （K））.展开更多
美国Maxell公司（Maxell Corporationl设计CR17450 and CR17335型先进的混合电池适用于各种工业标准规格．且比相同电池的容量要高出8％～9％。电池的运行温度范围在-40℃～80℃．并且有90℃～100℃的防热温度和内部瞬时短路防护功能。...美国Maxell公司（Maxell Corporationl设计CR17450 and CR17335型先进的混合电池适用于各种工业标准规格．且比相同电池的容量要高出8％～9％。电池的运行温度范围在-40℃～80℃．并且有90℃～100℃的防热温度和内部瞬时短路防护功能。这种超前的技术可以防止内部短路．并且使用非常安全。展开更多
文摘层状LiMnO2正极材料由于其高理论比容量(285 mAh g-1)、高能量密度、低成本引起了学者们的广泛注意。为了能制备出稳定的层状LiMnO2正极材料,并获得优良的循环性能,本文通过改进的高温固相法制备出了稳定的层状LiMnO2正极材料采用了XRD和电化学测试等手段对材料的晶体结构组成,电化学性能进行了测试表征,研究结果如下:本文成功合成了具有层状结构的LiMnO2正极材料。对其不同温度下合成的材料进行XRD测试以及电化学性能测试,发现不同温度下制备的LiMnO2正极材料均出现一定程度的团聚,且颗粒粒径分布不均匀;在0.1C放电倍率下,750℃下制备得到的LiMnO2正极材料具有最高的放电比容量(131 mAh g-1),经过60次循环后,材料放电比容量为100 mAh g-1,容量保持率为76.3%。
基金supported by the National Natural Science Foundation of China under grant No.59972026.
文摘Orthorhombic LiMnO2 cathode materials were synthesized successfully at lower temperature by sol-gel method. When LiMnO2 precursor prepared by sol-gel method was fired in air, the product was a mixture of spinel structure LiMn2O4 and rock-salt structure Li2MnO3, whereas in argon single-phase orthorhombic LiMnO2 could obtain at the range of 750℃ to 920℃. The substitution of Mn by Zn2+ or Co3+ in LiMnO2 led to the structure of LiMnO2 transiting to Qα-LiFeO2. The results of electrochemical cycles indicated that the discharged capacity of orthorhombic-LiMnO2 was smaller at the initial stages, then gradually increased with the increasing of cycle number, finally the capacity stabilized to certain value after about 10th cycles. This phenomenon reveals that there is an activation process for orthorhombic LiMnO2 cathode materials during electrochemical cycles, which is a phase transition process from orthorhombic LiMnO2 to tetragonal spinel Li2Mn2O4. The capacity of orthorhombic LiMnO2 synthesized at lower temperature is larger than that synthesized at high temperature.
文摘Composite materials composed of LiMnO2, a typical electrode material for lithium ion battery, and a chiral cyanide-bridged Ni（Ⅱ）-Fe（Ⅲ） coordination polymer [NiL2][Fe（CN）6]·4H2O （Ni-Fe, H-form） （L = （1R,2R）-（-）-1,2-cyclohexane-diamine） or its deuterium isomer, [NiL2][Fe（CN）6]·4D2O （Ni-Fe, D-form） have been prepared by the various ratios （w/w） of Ni-Fe：LiMnO2 = 10：0 （pure Ni-Fe）, 9：1, 8：2, 7：3, 6：4, 5：5, 4：6, 3：7, 2：8, 1：9 and 0：10 （pure LiMnO2）. Gradual shift of IR （infrared） spectra by changing the ratios and losing difference between H-form and D-form of Ni-Fe due to isotope effects revealed adsorption of Ni-Fe onto LiMnO2 to form composite materials. Formation of composite materials of Ni-Fe and LiMnO2 could be also proved losing ferromagnetic behavior of LiMnO2 on increasing of the ratios of Ni-Fe in each composite. In contrast to smoothly positive thermal expansion of pure LiMnO2 along the crystallographic b axis, variable temperature powder XRD （X-ray diffraction） patterns at 100-300 K of the composite materials exhibited thermally-accessible lattice distortion along the b axis with different ratios. It is also proved deviation of ideal linear correlation of an evaluation function, In K = a/T ＋ b （where, K = （d（T） - d（0））/d（T）, d（T） denotes nλ/（sin 2θ） at T （K））.
文摘美国Maxell公司（Maxell Corporationl设计CR17450 and CR17335型先进的混合电池适用于各种工业标准规格．且比相同电池的容量要高出8％～9％。电池的运行温度范围在-40℃～80℃．并且有90℃～100℃的防热温度和内部瞬时短路防护功能。这种超前的技术可以防止内部短路．并且使用非常安全。
文摘Mn Cl2、Li OH、EDTA和Na Cl O混合溶液一步水热反应合成锂离子电池正极材料正交LiMnO2(o-LiMnO2),进一步在反应体系中添加碳纳米管(CNTs)制备碳纳米管改性的o-LiMnO2(o-LiMnO2/CNTs复合材料)。采用X-射线衍射和扫描/透射电镜表征产物的晶体结构、微观形貌,循环伏安法和恒流充放电测试得活性材料电化学性能。结果表明,体系中nLi∶nMn控制为8∶1,在180℃反应24 h得到目标产物;反应体系中添加CNTs形成复合材料可降低o-LiMnO2颗粒粒径、提高导电率。o-LiMnO2首次放电容量为76.0 m Ah·g-1,100周后容量保持为124.1 m Ah·g-1;o-LiMnO2/CNTs复合材料首次及100周放电容量(基于o-LiMnO2/CNTs的质量)分别高达94.1和159.8 m Ah·g-1。
