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掺铬锂电池正E极材料 Li1+xCryMn2-y-xO4的合成及其结构性能的研究 总被引:4,自引:2,他引:2
利用液相合成法把掺元元素锂和铬同时均匀地掺入到主尖晶石相中,制得了颗粒细小、分布均匀及电化学性能优良的锂电池活性材料,利用X射线粉末衍射仪、Fourier变换红外分光光度计及电子显微镜对所合成成掺杂材料的结构进行表征,结果表明掺杂后晶胞发生收缩、Mn-O键增强、材料结构稳定、结晶性能好,电化学性能测试结果表明:混合掺杂锂铬元素可更好地改善材料的结构稳定性能,并获得较好初始容量及循环稳定性能。 相似文献
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锂钒氧化物Li1+δV3O8具有比容量高、循环寿命长、价格低等优点,因此它是一种非常有应用前景的锂离子蓄电池正极材料。作者采用传统的高温固相反应法合成了Ti、Fe、Ni、Co4种过渡金属元素部分取代Li1+δV3O8中钒的掺杂产物Li1+δMxV3-xO8,研究了不同掺杂元素及其掺杂量对材料电化学性能的影响。结果表明,掺杂Ti元素且掺杂量x≤0.1时,掺杂对材料的性能有一定的改善。掺杂没有提高其放电电压平台,降低了其比容量。但掺杂对其循环性能没有明显影响。综合考虑电化学性能,掺杂少量Ti比较适宜。 相似文献
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Fe(Ⅲ)和Al(Ⅲ)复合掺杂非晶态Ni(OH)_2的电极材料及性能 总被引:1,自引:0,他引:1
采用快速冷冻沉淀法首次成功制备出Fe(Ⅲ)和Al(Ⅲ)复合掺杂非晶态Ni(OH)2粉体材料。通过XRD、SAED、SEM、IR、Raman光谱及DSC-TG等对样品粉体的结构形态进行表征和分析,同时将样品合成电极材料并组装成MH/Ni模拟电池进行电化学性能测试,结果表明,样品材料内部结构缺陷多、无序性强、材料微粒大小比较均匀,并具有较好的分散性,结合水含量较多。将复合掺杂Fe(Ⅲ)5%和Al(Ⅲ)8%的样品材料制备镍正极并组装成MH/Ni模拟电池,在以80 mA·g-1恒流充电5.5 h,40 mA·g-1恒流放电,终止电压1.0 V的充放电制度下,进行充放电性能、比容量及其循环性能等电化学性能的测试,放电平台平稳,工作电压高达1.30 V,放电比容量达到357.6 mAh·g-1,且在电极过程中材料的稳定性增强、电化学阻抗较小,循环可逆性较好。 相似文献
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Li1+xNiyMn2-x-yO4材料的结构特征及电化学性能的研究 总被引:1,自引:0,他引:1
采用溶液相合成工艺在主尖晶石相锰酸锂中,掺入镍并对掺镍材料 电化学循环稳定性能进行了研究。利用扫描电镜,粉末X射线衍射仪,红外光谱仪以及阻抗分析仪对材料形貌及结构特征进行研究。结果表明掺杂镍可提高材料的结构稳定性能,增大材料的颗粒尺寸,减少材料的比表面积并能提高材料的结晶性能。掺杂镍可增强Mn-O键弱化Li-O键以减小锂离子在尖晶石相中的迁移电阻。电化学循环稳定性能测试表明在尖晶石相材料中掺杂镍可改善材料的循环稳定性能。 相似文献
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采用溶胶-凝胶法制备了F-和Cu2+复合掺杂的LiCu0.1Mn1.9O3.9F0.1锂离子电池正极材料. XRD和SEM表征表明合成产物具有良好的尖晶石结构,样品粒度为亚微米级,且分布均匀;电化学性能测试结果表明,掺杂后样品的电化学阻抗较小,首次放电容量达112 mA×h/g,充放电循环50次后,容量保持率为89.1%,电极材料具有较好结构稳定性和电化学性能. 同时还探讨了LiCu0.1Mn1.9O3.9F0.1的合成及掺杂机理. 相似文献
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采用快速冷冻沉淀法首次成功制备出Fe(Ⅲ)和Al(Ⅲ)复合掺杂非晶态Ni(OH)2粉体材料。通过XRD、SAED、SEM、IR、Raman光谱及DSC-TG等对样品粉体的结构形态进行表征和分析,同时将样品合成电极材料并组装成MH/Ni模拟电池进行电化学性能测试,结果表明,样品材料内部结构缺陷多、无序性强、材料微粒大小比较均匀,并具有较好的分散性,结合水含量较多。将复合掺杂Fe(Ⅲ) 5%和Al(Ⅲ) 8%的样品材料制备镍正极并组装成MH/Ni模拟电池,在以80 mA·g-1恒流充电5.5 h,40 mA·g-1恒流放电,终止电压1.0 V的充放电制度下,进行充放电性能、比容量及其循环性能等电化学性能的测试,放电平台平稳,工作电压高达1.30 V,放电比容量达到357.6 mAh·g-1,且在电极过程中材料的稳定性增强、电化学阻抗较小,循环可逆性较好。 相似文献
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Spherical lithium manganese oxide spinel was synthesized by an ultrasonic spray pyrolysis method, and has been characterized using X-ray diffraction, scanning electron microscopy, transimission electron microscopy and electrochemical cycling at 3 V regions. The LiMn2O4 powders were composed of about 10 nm-sized primary particles. The delivered discharge capacity of the synthesized nano-material was 125 mAh g−1 between 2.4 and 3.5 V and its retention was about 96% upon 50 cycling. From the high resolution transmission electron microscopic study, it was found that structural transition of the parent material did not occur even after the 50th electrochemical cycling on the 3 V region. It seems that the reversible structural change is possible for nanocrystalline LiMn2O4 as observed by the X-ray diffraction and transition electron microscopic observations. 相似文献
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《Ceramics International》2020,46(15):23773-23779
Lithium-rich layered oxides with high energy density have been intensively investigated as advanced lithium-ion batteries cathode materials. However, capacity degradation and voltage decay caused by irreversible lattice oxygen loss and structural transformation during cycling restrict their application. Herein, we proposed a high valance cations Nb5+ doping strategy and synthesized a series of Li1.2Mn0.54-x/3Ni0.13-x/3Co0.13-x/3NbxO2 (x = 0, 0.01, 0.02 and 0.03) cathode materials. The effects of Nb5+ doping on crystallographic structure and electrochemical property were systematically studied. In virtue of the large ionic radii and strengthened Nb–O bonds, the doped samples present commendable structural stability and expanded interlayer spacing for Li-ions migration, which ensures the upgraded cyclic stability and rate performance. In particular, the electrode with x = 0.02 delivers a discharge specific capacity of 265.8 mAh g-1 at 0.2 C with decelerated voltage decay, while 86.9% capacity are remained after long-term cycles. Moreover, excellent discharge specific capacity of 153.4 mAh g−1 is still attained at 5 C accompanied with enhanced Li-ion diffusion kinetics. 相似文献
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碳包覆对LiNi_(0.5)Mn_(1.5)O_4电化学性能的影响 总被引:1,自引:0,他引:1
以蔗糖为碳源,采用溶液沉积-真空热解法制备了LiNi_(0.5)Mn_(1.5)O_4/C复合材料。用热重与差热分析、X射线衍射分析、扫描电镜分析及电化学测试等手段对LiNi_(0.5)Mn_(1.5)O_4/C的微观结构、表面形貌和电化学性能进行了研究。结果表明,蔗糖热分解后在LiNi_(0.5)Mn_(1.5)O_4颗粒的表面包覆形成了一层无定形碳。无定形碳可以有效阻止LiNi_(0.5)Mn_(1.5)O_4颗粒的聚集,增加电极的导电面积,降低电池极化,从而改善LiNi_(0.5)Mn_(1.5)O_4的电化学性能。与未包覆的LiNi_(0.5)Mn_(1.5)O_4粉末相比,LiNi_(0.5)Mn_(1.5)O_4/C复合材料具有更高的可逆容量、更稳定的循环性能和更好的倍率性能。0.2C放电时,LiNi_(0.5)Mn_(1.5)O_4/C复合材料的首次放电容量达到144.8mA.h.g-1,经60次循环后平均每次循环的容量损失仅为0.0081%。而1.0C和2.0C放电时,LiNi_(0.5)Mn_(1.5)O_4/C复合材料的首次放电容量分别保持在131.9mA.h.g-1和122.4mA.h.g-1。 相似文献
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Dmitry V. Karpinsky Igor O. Troyanchuk Michael Tovar Vadim Sikolenko Vadim Efimov Ekaterina Efimova Vladimir Ya. Shur Andrei L. Kholkin 《Journal of the American Ceramic Society》2014,97(8):2631-2638
Bi1?xLaxFeO3 and Bi1?xPrxFeO3 ceramics of the compositions near the morphotropic phase boundary have been studied by X‐ray and neutron diffraction techniques and differential thermal analysis. The structural phases characterized by the long‐range polar, antipolar, and nonpolar ordering as well as the phase coexistence regions have been identified using the diffraction data depending on the dopant concentration and temperature. As a result of these studies the three phase region has been observed for the Pr‐doped compounds and the phase diagrams have been constructed. The detailed evolution of the structural parameters permitted to itemize the factors affecting the structural phase transitions and clarify the origin of the enhanced electromechanical properties in these materials. The performed structural analysis disclosed different character of the chemical bonds in the La‐ and Pr‐doped BiFeO3 compounds. Further, the role of the rare‐earth ions in the covalency of the chemical bonds is discussed. 相似文献
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《Ceramics International》2022,48(3):3374-3382
As one of the most promising cathode materials for next-generation of lithium-ion batteries, Li-rich Mn-based oxides are still hindered by inferior cycling properties and poor rate performance. Surface modification is proved to be feasible to tackle these problems. Herein, we chose phytic acid to construct spinel and Li3PO4 double protection layers on the Li1.2(Ni0.17Co0.07Mn0.56)O2 cathode material via a simple synchronous approach. The 3 wt% phytic acid treated sample achieves markedly enhanced electrochemical performance, such as elevated initial Coulombic efficiency reaching 90.0%, increased capacity retention of 87.8% after 150 cycles at 1 C and alleviated average discharge voltage drop of 1.63 mV per cycle. These impressive electrochemical properties can be ascribed to the designed hierarchical interface, which not only can synergistically retain structural stability but also provide fast Li+ transport channels. Taken together, this work employs a facile and novel route to enhance the electrochemical performance of Li1.2(Ni0.17Co0.07Mn0.56)O2, which may afford inspiration to the commercialization of Li-rich cathode materials. 相似文献
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Gd and Al co-doped LiMn2-x(GdAl)xO4 (x?=?0, 0.01, 0.02, 0.03, 0.04 and 0.05) materials with spinel structure were synthesized by sol–gel method. Powder X-ray diffraction results confirm the formation of cubic spinel structure and average particle sizes are found to be between 80 and 110?nm from FE-SEM and TEM analysis. Decrease in peak potential difference as a function of doping in Cyclic Voltammetry results establishes enhancement in Li+ intercalation and de-intercalation. Electrochemical Impedance Spectroscopy (EIS) results showed that accumulation of charges on electrode has improved with doping over pristine samples. At a doping of x?=?0.02 charge transfer resistance values were found to be least. First cycle charge–discharge profiles for LiMn1.96(GdAl)0.02O4 shows 139.2?mAh/g discharge capacity over other doped derivatives and pure LiMn2O4 (119.6?mAh/g) in aqueous Li2SO4 electrolyte. Doping of x?=?0.02 exhibit good cycling performance with only a total 4% capacity loss after 30 cycles. 相似文献
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采用"熔融浸渍法"合成了Mg和F共掺杂的不同温度下的锂离子电池正极材料Li Mn2-xMgxO3.97F0.03(x=0.05,0.1);煅烧温度为700,750和800°C。通过XRD对样品进行测试,样品为单一尖晶石结构的物相;并用SEM测试,对样品进行了形貌研究。用所制备的材料作为正极材料组装了模拟锂离子电池;在室温下进行恒电流充-放电性能测试,测试条件为3.3~4.3 V和0.2mA/cm2电流密度。随着材料制备温度的升高,电池的初始放电容量有逐渐增加的趋势,但充放电循环的容量损失也逐渐增加;氟掺杂量一定,镁掺杂量较多时,对应温度下煅烧的样品的结晶程度较好,样品的电化学性能也较好。在800下°C样品Li Mn1.9Mg0.1O3.97F0.03初始容量高达108 mAh/g,60次充放电循环后,其容量保持率高达81%,具有优良的循环稳定性能。 相似文献