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Yolk–Shell MnO@ZnMn2O4/N–C Nanorods Derived from α‐MnO2/ZIF‐8 as Anode Materials for Lithium Ion Batteries 下载免费PDF全文
Ming Zhong Donghui Yang Chenchao Xie Zhang Zhang Zhen Zhou Xian‐He Bu 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(40):5564-5571
Manganese oxides (MnOx) are promising anode materials for lithium ion batteries, but they generally exhibit mediocre performances due to intrinsic low ionic conductivity, high polarization, and poor stability. Herein, yolk–shell nanorods comprising of nitrogen‐doped carbon (N–C) coating on manganese monoxide (MnO) coupled with zinc manganate (ZnMn2O4) nanoparticles are manufactured via one‐step carbonization of α‐MnO2/ZIF‐8 precursors. When evaluated as anodes for lithium ion batteries, MnO@ZnMn2O4/N–C exhibits an reversible capacity of 803 mAh g?1 at 50 mA g?1 after 100 cycles, excellent cyclability with a capacity of 595 mAh g?1 at 1000 mAg?1 after 200 cycles, as well as better rate capability compared with those non‐N–C shelled manganese oxides (MnOx). The outstanding electrochemical performance is attributed to the unique yolk–shell nanorod structure, the coating effect of N–C and nanoscale size. 相似文献
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Editable Supercapacitors with Customizable Stretchability Based on Mechanically Strengthened Ultralong MnO2 Nanowire Composite 下载免费PDF全文
Zhisheng Lv Yifei Luo Yuxin Tang Jiaqi Wei Zhiqiang Zhu Xinran Zhou Wenlong Li Yi Zeng Wei Zhang Yanyan Zhang Dianpeng Qi Shaowu Pan Xian Jun Loh Xiaodong Chen 《Advanced materials (Deerfield Beach, Fla.)》2018,30(2)
Although some progress has been made on stretchable supercapacitors, traditional stretchable supercapacitors fabricated by predesigning structured electrodes for device assembling still lack the device‐level editability and programmability. To adapt to wearable electronics with arbitrary configurations, it is highly desirable to develop editable supercapacitors that can be directly transferred into desirable shapes and stretchability. In this work, editable supercapacitors for customizable shapes and stretchability using electrodes based on mechanically strengthened ultralong MnO2 nanowire composites are developed. A supercapacitor edited with honeycomb‐like structure shows a specific capacitance of 227.2 mF cm?2 and can be stretched up to 500% without degradation of electrochemical performance, which is superior to most of the state‐of‐the‐art stretchable supercapacitors. In addition, it maintains nearly 98% of the initial capacitance after 10 000 stretch‐and‐release cycles under 400% tensile strain. As a representative of concept for system integration, the editable supercapacitors are integrated with a strain sensor, and the system exhibits a stable sensing performance even under arm swing. Being highly stretchable, easily programmable, as well as connectable in series and parallel, an editable supercapacitor with customizable stretchability is promising to produce stylish energy storage devices to power various portable, stretchable, and wearable devices. 相似文献
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以非洲进口锰矿为原料,焦炭为还原剂,进行还原焙烧、硫酸浸出制备硫酸锰溶液。探究焦炭配比、焙烧温度、焙烧时间对锰还原效果的影响,确定最佳工艺参数,并对焙烧反应体系进行热力学分析及对浸出过程进行动力学分析。结果表明,最佳的焙烧条件为:焦炭配比15%、800℃焙烧60 min,锰的还原率达到97.84%。焙烧体系反应都是自发进行的,表观活化能为22.458 6 kJ/mol,且浸出过程受内扩散控制,动力学方程为:1-2x/3-(1-x)2/3=8.48exp(-22458.6/RT)×t。 相似文献
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Al掺杂对锰酸锂结构与性能的影响 总被引:2,自引:3,他引:2
采用固相法合成了Al掺杂的尖晶石LiAlxMn2-xO4(x=0~0.4).通过X射线衍射对LiAlxMn2-xO4的物相进行了研究,并探讨了Al掺杂对材料的充放电性能和电子电导率的影响.合成的LiAlxMn2-xO4均为纯尖晶石相.随着Al的掺入,LiAlxMn2-xO4的充放电循环性能得到改善,Al含量越高,循环过程中的容量衰减越小.电子电导率测试结果表明:掺杂Al后,降低了材料的电子电导率,这与Al的掺入降低了晶体中电子的离域作用有关. 相似文献
36.
Tong Gu Zhenghu Tong Xue Zhang Zhiyong Wang Zhen Zhang Tzann-Shun Hwang Lin Li 《International journal of molecular sciences》2022,23(11)
Mn(II)-oxidizing microorganisms are generally considered the primary driving forces in the biological formation of Mn oxides. However, the mechanistic elucidation of the actuation and regulation of Mn oxidation in soilborne bacteria remains elusive. Here, we performed joint multiple gene-knockout analyses and comparative morphological and physiological determinations to characterize the influence of carbon metabolism on the Mn oxide deposit amount (MnODA) and the Mn oxide formation of a soilborne bacterium, Escherichia coli MB266. Different carbon source substances exhibited significantly varied effects on the MnODA of MB266. A total of 16 carbon metabolism-related genes with significant variant expression levels under Mn supplementation conditions were knocked out in the MB266 genome accordingly, but only little effect on the MnODA of each mutant strain was accounted for. However, a simultaneous four-gene-knockout mutant (namely, MB801) showed an overall remarkable MnODA reduction and an initially delayed Mn oxide formation compared with the wild-type MB266. The assays using scanning/transmission electron microscopy verified that MB801 exhibited not only a delayed Mn-oxide aggregate processing, but also relatively smaller microspherical agglomerations, and presented flocculent deposit Mn oxides compared with normal fibrous and crystalline Mn oxides formed by MB266. Moreover, the Mn oxide aggregate formation was highly related to the intracellular ROS level. Thus, this study demonstrates that carbon metabolism acts as a pronounced modulator of MnODA in MB266, which will provide new insights into the occurrence of Mn oxidation and Mn oxide formation by soilborne bacteria in habitats where Mn(II) naturally occurs. 相似文献
37.
Viktria Hajdu Gbor Murnszky Mikls Nagy Erika Kopcsik Ferenc Kristly Bla Fiser Bla Viskolcz Lszl Vanyorek 《International journal of molecular sciences》2022,23(12)
Aniline (AN) is one of the most important compounds in the chemical industry and is prepared by the catalytic hydrogenation of nitrobenzene (NB). The development of novel, multifunctional catalysts which are easily recoverable from the reaction mixture is, therefore, of paramount importance. Compared to conventional filtration, magnetic separation is favored because it is cheaper and more facile. For satisfying these requirements, we developed manganese ferrite (MnFe2O4)–supported, magnetically separable palladium catalysts with high catalytic activity in the hydrogenation of nitrobenzene to aniline. In addition to high NB conversion and AN yield, remarkable aniline selectivity (above 96 n/n%) was achieved. Surprisingly, the magnetic support alone also shows moderate catalytic activity even without noble metals, and thus, up to 94 n/n% nitrobenzene conversion, along with 47 n/n% aniline yield, are attainable. After adding palladium nanoparticles to the support, the combined catalytic activity of the two nanomaterials yielded a fast, efficient, and highly selective catalyst. During the test of the Pd/MnFe2O4 catalyst in NB hydrogenation, no by-products were detected, and consequently, above 96 n/n% aniline yield and 96 n/n% selectivity were achieved. The activity of the Pd/MnFe2O4 catalyst was not particularly sensitive to the hydrogenation temperature, and reuse tests indicate its applicability in at least four cycles without regeneration. The remarkable catalytic activity and other favorable properties can make our catalyst potentially applicable to both NB hydrogenation and other similar or slightly different reactions. 相似文献
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目的 海洋资源调查是海洋科学研究的重要组成部分,对于开发利用海洋资源、保护海洋环境有重要意义。将深海高光谱图像用于调查洋底锰结核资源,相比传统图像方法信息更为全面,识别更为准确。但是高光谱方法中用于有监督分类识别的分类器需要人工标定的标签,这在深海环境中是较为困难的。针对这一局限性,本文提出了一种融合深度网络与模糊核聚类的深度模糊核聚类(deep kernel fuzzy C-means,DKFCM)算法,实现对洋底锰结核高光谱图像的无监督聚类。方法 DKFCM由随机深度卷积网络(Rdnet)及改进的模糊核聚类算法两大模块组成。Rdnet通过降维、随机图块卷积及非线性激活操作的循环,实现对高光谱图像浅层及深层特征的提取,融合这两类特征作为后续聚类识别的输入。改进的模糊核聚类算法先用欧氏距离计算初始聚类中心,再用模糊核聚类的方法以实现海洋资源的准确分类。结果 实验结果表明,DKFCM无监督聚类能有效聚类洋底资源,对锰结核的聚类准确率达到76.59%,相比单用K-means聚类提高了20.99%,相比经Rdnet提取特征后再用K-means聚类提高了13.76%,对比实验表明DKFCM算法在无标签数据的情况下也能达到良好的准确率。结论 本文所提的高光谱深度模糊核聚类方法,实现了深海锰结核的无监督聚类,可以用于海洋资源量的评估。 相似文献