α-MnO2纳米棒在1 mol/L KOH溶液中的电容行为

通过水热法合成的MnO2纳米粉体,用X射线衍射(XRD)证明其为α MnO2,透射电镜(TEM)证明颗粒形貌为棒状,直径20nm左右,长度在0 5～1 0μm之间。用循环伏安、恒电流充放电、交流阻抗等方法研究了该MnO2电极在1mol LKOH溶液中,-0 25～0 45V(vs·Hg HgO)的电位范围内的法拉第"准电容行为"。结果表明:该MnO2电极在1mol LKOH中具有良好的电容性能,其比电容可达300F g以上,在5mA cm2的电流密度下恒电流充放1000个循环后,其容量衰减在10%以内。     

镧改性二氧化锰电极超大容量电容器的研究

通过KMnO4 和MnCl2 的低温固相反应 ,制备了掺杂稀土氧化镧的二氧化锰超大容量电容器复合正极材料。X射线衍射 (XRD)分析表明 ,所制备复合电极材料中的MnO2 是其α与γ相的混合晶相。透射电镜分析 (TEM )表明 ,复合材料呈棒状结构 ,其平均长度为 2 5 0～ 3 5 0nm ,平均直径为 15～ 2 0nm ,长径比大于 15。通过对新型复合电极材料进行电化学性能测试表明 ,掺入氧化镧的复合电极材料具有更好的充放电性能和电容特性 ,当MnO2 与La2 O3的质量比为 1∶0 .1时 ,复合电极在 2mol·L- 1 (NH4 ) 2 SO4 溶液中单电极最大放电比容量可达 15 6.15F·g- 1 ,比纯二氧化锰电极提高了 5 4.6% ,充放电效率提高了 19.5 %。     

纳米MnO2超级电容器性能研究

采用液相反应制备了纤维状纳米MnO2，X射线衍射分析表明：产物是α-MnO2和7-MnO2组成的混合晶相。利用循环伏安和恒流充放电测试其电化学性能。在0．15V～0．75V(SCE)工作电压范围内考察了在不同浓度(NH4)2SO4电解液中的电容性能，结果表明：该电极材料在浓度为1mol／L的(NH4)2SO4中具有优异的电容性能；恒流充放测试其比容量可达142．2F／g。     

MnO2/AC复合材料的机械化学法制备及其电容性能

采用机械化学法制备MnO2以及MnO2/AC复合电极材料.用X射线衍射（XRD）和扫描电镜（SEM）研究了所合成材料的晶型与形貌;用循环伏安、交流阻抗和恒流充放电对电极在6 mol/LKOH电解液中的电容性能进行了测试.结果发现,加入活性炭后,MnO2超级电容器放电电压从1.2 V提高到1.8 V;电极比容量达到了312 F/g,经过300次循环后为260 F/g.     

花状Co–Ni氢氧化物电极材料的制备与电化学特性

采用原位生长法, 以硝酸钴和氨水为原料、硝酸铵为生长剂, 制备生长在泡沫镍上的Co (OH)₂电极材料, 并在此基础上对其进行镍添加改性, 旨在得到比电容高、循环性能好的Co–Ni氢氧化物电极材料。通过X射线衍射仪、扫描电子显微镜对Co–Ni氢氧化物电极材料进行物相和微观形貌分析; 通过循环伏安、恒流充放电和交流阻抗等方法对Co–Ni氢氧化物电极材料的电化学性能进行分析和表征。结果表明: 镍添加使材料从原有的Co (OH) ₂晶相变为Co (OH) ₂和Ni (OH) ₂双晶相材料, 使原有的簇状结构转变为更利于离子扩散的花状结构, 进而促进材料电化学性能的提高。当Co/Ni摩尔比为3:1时制得的花状Co–Ni氢氧化物电极材料的电化学性能最好, 在5 m V·s-1扫速下的比电容值为3674.7 F·g-1, 在5 A·g-1电流密度下的比电容值为1450.0 F·g-1, 在20 A·g-1电流密度下循环5000次的比电容保持率为77.1%。     

α-MnO2的机械化学法合成及其电容性质

以高锰酸钾与乙酸锰为原料,采用机械化学法制备MnO2.利用SEM、BET、XRD、交流阻抗法、循环伏安以及恒电流充放电对电极材料结构与性能表征,对充放电曲线求斜率分析.结果表明产物为弱结晶型α-MnO2,其比表面积为385.5 m2,平均孔径为3.4 nm.α-MnO2电化学电容器表现出法拉第电容与双电层电容的双重特征;随着循环次数增加,Mn3O4生成,交换电流密度从177 mA/g减少到69.8 mA/g,微分电容从2.40×10-1 F减少到1.91×10-3 F;电极过程主要受电极电位状态变量影响;电极最大比容量达到416 F/g,经过近500次循环后,比容量为220 F/g.     

掺杂稀土金属改性二氧化锰/活性碳超级电容器的研究

以KMnO4, Mn（CH3COO）2·4H2O和活性碳为原料, 利用化学共沉淀法, 合成氧化锰/活性碳（MnO2/AC）电极材料, 同时在制备过程中分别掺杂硫酸钴（CoSO4）和氧化铒（Er2O3）、硫酸钴和硫酸镧 （La2（SO4）3）、硫酸钴和硫酸镍（NiSO4）. 采用X射线衍射（XRD）和扫描电子显微镜（SEM）分析了MnO2/AC的结晶结构及表面形态. 采用循环伏安 （CV）和恒流充放电技术研究了MnO2/AC的电化学性能. 结果表明, 掺杂Co和稀土元素La及Er的MnO2/AC比未掺杂的具有更宽的窗口电位, 表现出更好的电容性能. 掺杂后的MnO2/AC内阻值有所增加, 电容量有所减少. MnO2/AC电容为275 F·g^-1, 掺Co和La的为200 F·g^-1, 掺Co和Er的为193 F·g^-1, 掺Co和Ni的为174 F·g^-1.     

熔盐法制备二氧化锰及放电性能研究

以金属锰粉和高锰酸钾为原料,采用熔盐法在KCl-NaCl体系和NaNO3体系中成功地合成了二氧化锰(MnO2)电极材料。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的结构与形貌进行了表征,结果表明:合成样品为单斜晶系产物,粉末样品为片状结构。在c(KOH)=9mol/L电解液中采用三电极体系对样品进行恒电流放电和循环伏安测试,结果显示该材料在电流密度为250 mA/g时,单电极放电比容量达到251.3 mAh/g,是电解二氧化锰(EMD)的2.5倍。     

电沉积法制备石墨烯/MnO_2纳米复合电极的电容性能

采用循环伏安法,先在泡沫镍基体上沉积多孔结构的MnO_2纳米片,然后再沉积一层还原石墨烯,得到石墨烯/MnO_2复合材料。采用扫描电镜(SEM)、X射线衍射仪(XRD)与X射线光电子能谱仪(XPS)分析该材料的形貌、结构与价态。采用循环伏安、恒流充放电和电化学交流阻抗技术测试材料的比电容、循环稳定性和阻抗。结果表明,MnO_2为纳米片状结构,石墨烯基本覆盖了MnO_2沉积层。MnO_2与石墨烯复合后,等效串联电阻由0.83Ω减小到0.4Ω,电荷转移电阻由9.34Ω下降到6.76Ω。在2 A/g充放电电流密度下,石墨烯/MnO_2复合电极的比电容为501 F/g,比MnO_2增大25%,在充放电循环3 000次后电容保持率为84%。     

可控合成纳米MnO2及电化学性能研究

以高锰酸钾和硫酸锰为原料,采用水热法在相同的反应体系中分别合成了α-MnO2纳米棒和β—MnO2纳米柱,采用XRD,SEM,TEM和BET等分析手段对样品形貌和结构进行表征。结果表明：在MnSO4和KMnO4物质摩尔比为3：2的中性水热反应体系中,反应温度是影响产物形貌和晶型的重要因素。当反应温度在120℃,反应24h时,所得产物为α—MnO2纳米棒和纳米颗粒混合物。当反应温度在150℃,反应24h时,所得产物为β-MnO2纳米柱。BET结果显示,两者的比表面积达118．7m^2／g和84．3m^2／g。采用循环伏安、恒流充放电等方法对产物的电化学性能进行表征。结果表明：α—MnO2的电化学性能明显好于β-MnO2,在-0．2～0．8V的电压范围内,以2．5mA的电流充放电时,α-MnO2的最大比电容是133．2F／g,经过100次循环后容量仍保持在90％以上。     

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.