掺钴对尖晶石型LiMn_2O_4正极材料性能影响

采用固相合成法制备了锂离子电池正极材料用尖晶石型LiMn2O4正极材料,并通过加入Co对材料进行了掺杂改性研究;用X射线衍射(XRD)和扫描电镜(SEM)研究了材料的晶体结构和微观形貌,充放电循环实验对材料的电化学性能进行了测试。结果表明:纯相尖晶石型LiMn2O4初始放电比容量为118.91 mA.h/g,循环25次后放电比容量为107.03mA.h/g,比容量保持率为90.01%;掺杂Co的材料同样具有尖晶石型结构,初始放电比容量略有降低,但循环性能有明显改善,掺Co改性样品Li1.05Co0.04Mn1.96O4的初始放电比容量为114.55mA.h/g,25次充放电循环后,放电比容量为105.76mA.h/g,比容量保持率为92.33%。     

锂离子电池正极材料LiMn2O4的改性研究

为改善尖晶石LiMn2O4的循环性能，采用高温固相法合成了由Li2CO3改性的尖晶石锂锰氧化物，研究了Li2CO3添加量对LiMn2O4性能的影响。通过XRD，Rietveld精细XRD分析和模拟电池等方法对产物的结构和电化学性能进行了表征与测试。结果表明，部分Li进入到尖晶石LiMn2O4的晶格中，增强了材料充放电循环过程中的结构稳定性。随着Li2CO3量的增加，产物的循环稳定性增加。当Li2CO3的加入量为0．06摩尔比时，10次循环后的高温容量衰减由改性前的15％降低到6．8％。     

锂离子电池正极材料LiMn2-xNdxO4的性能研究

采用高温固相反应法,合成了具有尖晶石结构的锂离子电池正极材料LiMn2O4,并对其掺杂不同量的Nd,得到LiMn2-xNdxO4(x=0～0.03).对材料进行了XRD、粒度分析及恒电流充放电测试.试验结果表明,掺杂微量稀土元素Nd合成的正极材料具有标准尖晶石结构,较好的循环稳定性.其中LiMn0.995Nd0.005O4具有较好的电化学性能和循环稳定性,最高容量达到132mAh·g-1.     

不同锂源对尖晶石锰酸锂性能的影响

采用溶胶凝胶法,以氢氧化锂、醋酸锂、硝酸锂为锂源制备锂离子电池正极材料尖晶石LiMn2O4,分别用XRD和SEM对产物的结构和微观形貌进行表征,并对其电化学性能进行了测试。结果表明,用硝酸锂制备的LiMn2O4有较好的的微观形貌及较高的初始比容量,用氢氧化锂制备的LiMn2O4有较好的循环性能。     

LiCrxNi0.2-xMn1.8O3.95F0.05的合成与电化学性能研究

采用sol—gel法合成了尖晶石型LiMn2O4，铬、镍、氟复合掺杂LiCrxNi0．2-xMn1．8O3．95F0．055(x=0．05，0．1，0．15)。XRD研究表明所合成的样品均为尖晶石结构；研究表明：铬、镍、氟复合掺杂样品常温循环稳定性明显提高，复合掺杂对高温性能有一定改善。     

合成条件对锂离子正极材料LiMn_2O_4电性能影响

利用实验室自制的Mn（OH）2沉淀,采用改性的固相法合成尖晶石LiMn2O4,并且系统地研究了温度、锂配比量和升温速率对LiMn2O4电性能的影响.通过对材料进行扫描电子显微镜（SEM）和X射线衍射光谱（XRD）分析以及电性能测试,结果表明：合成出的物质为标准的尖晶石结构,衍射峰与标准的LiMn2O4结构完全对应,为尖晶石结构;最佳合成条件：合成温度为830℃,Li/2Mn=1.05,升温速率为5℃/min.组装成AA电池后电池的首次循环性能都达到100 mAh/g.     

层状Ni-Mn基锂离子电池正极材料进展

层状Ni—Mn基锂离子电池正极材料具有层状结构镍酸锂(LiNiO2)的高比容量以及尖晶石型结构锰酸锂(LiMn2O4)的高安全性、低价格等特点，是最有可能代替或部分代替LiCoO2的新型正极材料用于小型锂离子电池，同时也可望用作低成本、高安全性和大容量动力型锂离子电池的正极材料。本文综述了层状Li—Ni—Mn—O系化合物和LiNi1/3Mn1／3Co1/3O2的合成工艺、结构特点和电化学性能，阐述了层状Ni—Mn基锂离子电池正极材料的发展、研究开发现状和应用前景。     

Mn1.5-0.5xCo1.5-0.5xCuxO4尖晶石粉体及涂层的制备与性能

采用溶胶-凝胶法制备Mn1.5-0.5xCo1.5-0.5xCuxO4(x=0、0.1、0.2、0.3和0.4,摩尔分数)尖晶石粉体,并将该粉体涂覆在SUS 430合金表面,经高温烧结后制成涂层。研究Cu含量对尖晶石的晶体结构、热膨胀行为和高温电导率的影响,测试Mn1.35Co1.35Cu0.3O4涂层的抗氧化性能。结果表明:随Cu含量增加,Mn1.5-0.5xCo1.5-0.5xCuxO4尖晶石的物相组成由立方-四方复合相逐渐转变为纯立方相。当x=0时,物相为立方-四方复合相;x≥0.2时,物相转变为纯立方相。尖晶石的热膨胀系数(CTE)随Cu含量增加而增大,原本出现在500℃左右CTE降低的现象被抑制。在30~800℃范围内,Mn1.35Co1.35Cu0.3O4尖晶石涂层的CTE与SUS 430不锈钢相匹配(分别为12.45×10-6和12×10-6~12.4×10-6 K-1)。此外,该尖晶石的高温电导率随Cu含量增加而升高,800℃以下电导率均大于1.3 S/cm,符合连接体材料电导率的要求。涂覆Mn1.35Co1.35Cu0.3O4尖晶石涂层后,SUS 430合金在800℃的氧化速率下降87.5%。因此,涂覆Mn1.35Co1.35Cu0.3O4尖晶石涂层的SUS 430合金可以用作固体氧化物燃料电池(SOFC)连接体。     

尖晶石型LiMn2O4正极材料的改性及电化学性能研究

采用共沉淀方法合成了尖晶石型LiMn2O4正极材料，并对其工艺进行改进，进行锰源掺杂及Al2O3包覆改性等得到5种材料。首次充放电容量较高，所得纯相尖晶石的首次充放电容量达到130mAh／g，充放电效率高，电化学性能较好。对5种材料进行了XRD以及充放电，循环伏安及交流阻抗测试，考察了不同掺杂元素对电池材料的影响，得出在掺杂工艺相同的条件下，掺Cr所得材料的电化学性能较为理想，循环伏安和交流阻抗测试亦为上述结果进行了有力佐证。     

锂离子电池正极材料LiMn2O4的研究现状

对近年来国内外有关尖晶石型LiMn2O4材料合成的研究作了综述。从掺杂改性，表面改性和电解液优化等几个角度分析了LiMn2O4容量衰减的改善及循环性能提高，并初步分析了尖晶石型锰酸锂的容量衰减机理。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.