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61.
Li2MnO3-based composite cathodes for lithium batteries: A novel synthesis approach and new structures 总被引:1,自引:0,他引:1
J.R. Croy S.-H. Kang M. Balasubramanian M.M. Thackeray 《Electrochemistry communications》2011,13(10):1063-1066
A new, simple technique has been demonstrated for fabricating high-capacity composite electrode structures. In this technique, Li2MnO3 is leached in acid in the presence of soluble transition metal ions and subsequently annealed between 450 and 850 °C. The technique can be used to prepare a wide variety of composite compounds, in particular, a new family of ‘layered–rocksalt’ xLi2MnO3·(1−x)MO (e.g., M = Ni and Co) structures and modifications thereof, as well as ‘layered–layered’ xLi2MnO3·(1−x)LiMO2 (e.g., M = Mn, Ni, and Co) and ‘layered–spinel’ xLi2MnO3·(1−x)LiM2O4 (e.g., M = Mn and Ni). This novel approach also holds promise for 1) synthesizing materials that reduce the extent of internal phase transitions of composite cathode structures with a high manganese content, and 2) minimizing the extent to which cells need to be electrochemically activated to remove Li2O, thereby reducing the extent of the irreversible capacity loss on the first charge/discharge cycle. 相似文献
62.
将氢氧化物共沉淀法制备的(Ni1/3Co1/3Mn1/3)(OH)2在500℃热处理5 h得到具有尖晶石结构、纳米尺寸的氧化物M3O4(M=Ni1/3Co1/3Mn1/3).将其与LiOH及不同量的纳米MgO混合均匀,并在850℃热处理24 h制备了Li(Ni1/3Co1/3Mn1/3)1/xMgxO2(x=0,0.01,0.02,0.03,0.04,0.05)正极村料.随着Mg掺杂量的增大,正极材料的晶胞参数增大;少量的Mg掺杂增大了锂离子的扩散系数,而过度掺杂却使锂离子扩散系数有所降低,其中Li(Ni1/3Co1/3Mn1/3)0.98Mg0.02O2的锂离子扩散系数最大,其脱出和嵌入扩散系数分别为DLi-dein=29.20×10-11cm2·S-1和DLi-in=4.760×10-11cm2·s-1;其以3C倍率充放电的平均放电比容量为139.3 mAh·g-1,比未掺杂的原粉约高9.5 mAh·g-1;另外其循环性能也得到了大幅度改善. 相似文献
63.
研究了以泡沫镍载NiCo2O4纳米线阵列为阴极催化剂的Al-H2O2半燃料电池的性能. 以无模板生长法制备了泡沫镍载NiCo2O4纳米线阵列阴极材料, SEM测定结果表明, NiCo2O4纳米线几乎垂直于泡沫镍载体表面生长. 以电压和功率密度-电流密度曲线研究了H2O2浓度、电解液流速和温度对电池性能的影响, 结果显示, 以铝片为阳极, 0.6 mol/L H2O2为氧化剂的电池的开路电压约为1.40 V; 在室温和57 ℃下, 电流密度为98和172 mA/cm2时, 最大功率密度分别达到79和120 mW/cm2. 在5000 s的测试时间内, 0.70 V的恒电流密度和75 mA/cm2 的恒电压值几乎为一常数, 这表明以泡沫镍载NiCo2O4纳米线阵列为催化剂电还原H2O2具有很好的活性、稳定性和传质性能. 相似文献
64.
Structure Design and Performance of LiNixCoyMn1‐x‐yO2 Cathode Materials for Lithium‐ion Batteries: A Review 下载免费PDF全文
Xinru Zhao Jinxian Wang Xiangting Dong Guixia Liu Wensheng Yu Limin Wang 《中国化学会会志》2014,61(10):1071-1083
Lithium‐ion batteries are now considered to be the technology of choice for future hybrid electric and full electric vehicles to address global warming. One of the challenges for improving the performance of lithium ion batteries to meet increasingly demanding requirements for energy storage is the development of suitable cathode materials. The recent advancement of lithium nickel cobalt manganese oxides are investigated as advanced positive cathode materials for lithium‐ion batteries. This review aims at providing the reader with an understanding of the critical scientific challenges facing the development of LiNixCoyMn1‐x‐yO2 materials, the latest developments in crystal structure, synthesis methods, and structure designs to unravel the mechanisms of charge and mass transport processes associated with battery performance, and the outlook for future‐generation batteries that exploit gradient structures materials for significantly improved performance to meet the ever‐increasing demands of emerging technologies. 相似文献
65.
Fu Qiang KeNing Sun NaiQing Zhang ShiRu Le XiaoDong Zhu JinHuo Piao 《Journal of Solid State Electrochemistry》2009,13(3):455-467
A-site-deficient perovskite cathode material La0.58Sr0.4Co0.2Fe0.8O3 − δ
(L58SCF) is coated on the yttria-stabilized zirconia electrolyte by screen-printing technique. Several key fabrication parameters
including selection of additives (binder and pore former), effect of coating thickness, sintering temperature and time on
the microstructure, and electrochemical performance of cathode are investigated by scanning electron microscopy and electrochemical
impedance spectroscopy. We study the microstructure and the electrochemical property of the cathode with different kinds of
additives. Results show that the cathode possesses fine microstructure, enough porosity, and ideal electrochemical property
when polyvinyl butyral serves as both binder and pore former in the cathode. The cathode with three screen-printing coats
(thickness 28 ± 7 μm, weight 6.07 ± 0.72 mg cm−2) sintering at 1,000 °C for 2 h shows lower polarization resistance of 0.183 Ω cm2 at 800 °C. Based on the optimized parameters, the polarization resistances of the L58SCF–Ce0.8Gd0.2O1.9 – δ
composite cathode display the R
p values of 0.067 Ω cm2 at 800 °C, 0.106 Ω cm2 at 750 °C, 0.225 Ω cm2 at 700 °C, and 0.550 Ω cm2 at 650 °C. 相似文献
66.
采用水热法制备了系列富锂尖晶石型正极材料Li2+4xMn0.6+2xNi0.6-6xCr0.8O4(x=1/30,1/20,1/15,1/12),通过X射线衍射(XRD)、电感耦合等离子体-原子发射光谱(ICP-AES)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FTIR)、拉曼光谱、循环伏安(CV)和充放电测试等手段对其结构及电化学性能进行表征.结果表明,所制备的系列材料为富锂型高电压尖晶石结构正极材料,该系列样品在4.7 V左右有放电平台.x=1/15和x=1/12时,样品中的Cr为+3价,没有观测到Cr6+.随着x值的增大,样品中Li离子与过渡金属离子的混排减小,样品的充放电比容量逐渐增大,且2.7 V处的放电平台容量也增加.当x=1/12时,样品具有较好的充放电比容量和倍率特性,首次放电比容量为107.3 mA·h/g,20次循环后容量保持率为84.9%. 相似文献
67.
以柠檬酸为螯合剂和还原剂, NH4VO3为钒源,通过溶胶-凝胶法制备了锂离子电池正极材料Li3V2(PO4)3及其三元掺杂体系Li2.85Na0.15V1.9Al0.1(PO4)2.9F0.1.分别采用X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、能量损失谱(EELS)、拉曼(Raman)光谱、扫描电子显微镜(SEM)、X射线能谱(EDS)、恒流充放电、循环伏安(CV)和交流阻抗谱(EIS)等技术对材料的微观结构、颗粒形貌和电化学性能进行分析.结果表明:在残余碳包覆的基础上, Na、Al、F三元掺杂有利于稳定Li3V2(PO4)3的晶体结构,进一步减少颗粒团聚和提升材料导电特性,促进第三个锂离子的脱出和嵌入,从而显著改善Li3V2(PO4)3的实用电化学性能.未经掺杂的Li3V2(PO4)3原粉在1/9C、1C和6C倍率下的可逆比容量分别为141、119和98 mAh·g-1,而三元掺杂改性材料在1/9C、1C、8C和14C倍率下的比容量分别为172、139、119和115 mAh·g-1.在1C倍率下循环300圈后,掺杂体系的比容量依然高达118 mAh·g-1,比原粉高出32.6%.值得注意的是,这种三元掺杂还使Li3V2(PO4)3的多平台放电曲线近似转变为一条斜线,显示出可能不同的储锂机制. 相似文献
68.
Degradation induced by sodium chloride in air was investigated for (La0.8Sr0.2)0.98MnO3(LSM) and La0.6Sr0.4Co0.2Fe0.8O3(LSCF) cathodes in solid oxide fuel cells(SOFC). Cell performance was measured by volatilizing NaCl to be supplied to the cathode at a constant current density of 200 mA/cm2 for up to 100 h. At 800 ℃, an exposure of the cathode to 30 mg/L NaCl caused negligible degradation of LSM at least for 100 h. Slight change in the composition of the cathode materials was observed which may imply the gradual degradation of cell performance for the long-term. In addition, cell performance degradation was compared between 700 ℃ and 900 ℃, being poisoned by 30 mg/L NaCl. Degradation was negligible for LSM cathode, while LSCF cathode showed slightly poor tolerance at 700 ℃ due to the decomposition of the cathode material. Further studies should be done to clarify the long-term influence of NaCl on cathode performance. 相似文献
69.
以氢氧化锂、乙酸锰、硝酸镁和钛酸丁酯为原料, 以柠檬酸为螯合剂, 采用溶胶-凝胶法制备了二价镁离子与四价钛离子等摩尔共掺杂的尖晶石型锂离子电池正极材料LiMn1.9Mg0.05Ti0.05O4. 采用热重分析(TGA), X射线衍射(XRD), 扫描电子显微镜(SEM), 透射电子显微镜(TEM)和电化学性能测试(包括循环伏安(CV)和电化学交流阻抗谱(EIS)测试)对所得样品的结构、形貌及电化学性能进行了表征. 结果表明: 780℃下煅烧12 h 得到了颗粒均匀细小的尖晶石型结构的LiMn1.9Mg0.05Ti0.05O4材料, 该材料具有良好的电化学性能, 在室温下以0.5C倍率充放电, 在4.35-3.30 V电位范围内放电比容量达到126.8 mAh·g-1, 循环50 次后放电比容量仍为118.5mAh·g-1, 容量保持率为93.5%. 在55℃高温下循环30次后的放电比容量为111.9 mAh·g-1, 容量保持率达到91.9%, 远远高于未掺杂的LiMn2O4的容量保存率. 二价镁离子与四价钛离子等摩尔共掺杂LiMn2O4, 改善了尖晶石锰酸锂的电子导电和离子导电性能, 使其倍率性能和高温性能都得到了明显的提高. 相似文献
70.