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排序方式: 共有322条查询结果,搜索用时 15 毫秒
1.
以三氯乙烷和二氯乙烷为原料, 金属钠为还原剂, 在溶剂热条件(100~150 ℃)下使氯代乙烷中的碳氯键和碳氢键发生断裂制备了碳纳米球, 并对制备的碳纳米球进行了表征. X射线衍射结果表明, 样品为类石墨结构, 衍射信号宽且弱, 表明样品的结晶性较差; 拉曼光谱分析结果也表明样品具有较高的无序度. 样品的SEM与TEM分析结果表明, 在较高的反应温度下, 碳球具有更好的单分散性, 碳球的粒径随温度的升高而增大; 选区电子衍射结果表明碳球内部为无定形的类石墨结构. 以碳纳米球为负极材料的锂离子电池测试结果表明, 50周循环后比容量为941 mA·h/g, 库仑效率接近100%, 放电容量保持率为103.7%, 具有良好的循环稳定性. 测试了不同温度下制备样品的超级电容器性能, 发现120 ℃下制备的碳纳米球具有较高的比电容和较低的内阻值, 比电容高达130 F/g, 经过1000周循环充放电后比电容衰减比例低于14%, 具有较高的稳定性. 相似文献
2.
The Carbon sphere@Nickel sulfide core-shell nanocomposites for different mole ratios of Carbon sphere (0:1; 0.5:1 and 1:1) have been synthesized by a facile low temperature water-bath method without any further calcination. XRD studies on the core-shell nanocomposites show that characteristic peaks associated with rhombohedral phase structure of nickel sulfide have been retained. TEM morphology presents the interlinked core-shell of Carbon sphere@Nickel sulfide composite with grass-leaf dexterity for better ionic diffusion. BET study confirms the formation of mesoporous structure with high surface area. The existence of elements and its electronic configuration is noted through XPS. The electrochemical studies on pristine nickel sulfide and its Carbon sphere@Nickel sulfide core-shell composites reveal that Carbon sphere@Nickel sulfide (0.5:1) exhibits high specific capacitance of 1022?F?g?1 at a current density of 1?A?g?1. It shows good cyclic performance even beyond 4000 consecutive charge/discharge cycles at a relatively high current density of 20?A?g?1 with the ~83% of retention. 相似文献
3.
《Current Applied Physics》2020,20(5):605-610
Electrochemical capacitors (referred to as supercapacitors) have high power density, long cycling stability, and are eco-friendly for use in electronic applications. The proper and stable utilization of supercapacitor systems can expand the practical scope of energy-powering applications in various device platforms. Nevertheless, the low energy density of conventional oxide and sulfide electrode materials still limits the practical realization of supercapacitor devices in real electronic applications. This limitation results from the poor surface stability, structural collapse, and low electrical conductivity of the oxide and sulfide materials. Single metal electrodes with multivalent metal ions exhibit promising energy-storing kinetics and may be viable alternatives to these oxide and sulfide electrode materials. Here, we report a metal zinc (Zn) electrode supercapacitor (ZIC) consisting of a thin-walled architecture as an electrode by means of a voltage-controlled electroplating method. The optimized ZIC exhibited excellent pseudo-capacitive performance, excellent high-rate performance, and an outstanding cycling stability. 相似文献
4.
Xiaotong Fan Dr. Kai Huang Prof. Long Chen Haipeng You Menglei Yao Prof. Hao Jiang Prof. Ling Zhang Prof. Cheng Lian Dr. Xiangwen Gao Prof. Chunzhong Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202215342
Supercapacitor represents an important electrical energy storage technology with high-power performance and superior cyclability. However, currently commercialized supercapacitors still suffer limited energy densities. Here we report an unprecedentedly respiring supercapacitor with chlorine gas iteratively re-inspires in porous carbon materials, that improves the energy density by orders of magnitude. Both electrochemical results and theoretical calculations show that porous carbon with pore size around 3 nm delivers the best chlorine evolution and adsorption performance. The respiring supercapacitor with multi-wall carbon nanotube as the cathode and NaTi2(PO4)3 as the anode can store specific energy of 33 Wh kg−1 with negligible capacity loss over 30 000 cycles. The energy density can be further improved to 53 Wh kg−1 by replacing NaTi2(PO4)3 with zinc anode. Furthermore, thanks to the extraordinary reaction kinetics of chlorine gas, this respiring supercapacitor performs an extremely high-power density of 50 000 W kg−1. 相似文献
5.
《中国化学快报》2021,32(8):2453-2458
In power storage technology,ion exchange is widely used to modify the electronic structures of electrode materials to stimulate their electrochemical properties.Here,we proposed a multistep ion exchange(cation exchange and anion exchange) strategy to synthesize amorphous Ni-Co-S and β-Co(OH)_2 hybrid nanomaterials with a hollow polyhedron structures.The synergistic effects of different components and the remarkable superiorities of hollow structure endow Ni-Co-S/Co(OH)_2 electrode with outstanding electrochemical performance,including ultra-high specific capacity(1440.0 C/g at 1 A/g),superior capacitance retention rate(79.1% retention at 20 A/g) and long operating lifespan(81.4% retention after5000 cycles).Moreover,the corresponding hybrid supercapacitor enjoys a high energy density of 58.4 Wh/kg at the power density of 0.8 kW/kg,and a decent cyclability that the capacitances are maintained at80.8% compared with the initial capacitance.This research presents a high-performance electrode material and provides a promising route for the construction of electrode materials for supercapacitors with both structural and component advantages. 相似文献
6.
Mingsheng Xu Mingze Sun Sajid ur Rehman Kangkang Ge Xiaolong Hu Haizhen Ding Jichang Liu Hong Bi 《中国化学快报》2021,32(6):2027-2032
The high specific capacitance along with good cycling stability are crucial for practical applications of supercapacitors,which always demands high-performance and stable electrode materials.In this work,we report a series of ternary composites of CoO-ZnO with different fractions of reduced graphene oxide(rGO) synthesized by in-situ growth on nickel foam,named as CZG-1,2 and 3,respectively.This sort of binder-free electrodes presents excellent electrochemical properties as well as large capacitance due to their low electrical resistance and high oxygen vacancies.Particularly,the sample of CZG-2(CoO-ZnO/rGO 20 mg) in a nanoreticular structure shows the best electrochemical performance with a maximum specific capacitance of 1951.8 F/g(216.9 mAh/g) at a current intensity of 1 A/g.The CZG-2-based hybrid supercapacitor delivers a high energy density up to 45.9 Wh/kg at a high power density of 800 W/kg,and kept the capacitance retention of 90.1% over 5000 charge-discharge cycles. 相似文献
7.
《中国化学快报》2021,32(11):3359-3363
The electrode/electrlyte interface is of great signifance to photoelectrochemical (PEC) water oxidation as the reaction mainly occur here. Herein, we focus on the effect of supercapactance of the electrode/electrlyte interface on the performance of PEC. It is discovered that the supercapacitor on the interface is crucial because it links the charge transport and solution ion adsorption on its two sides. In this study, we demonstrate an approach to promote the performance of TiO2 nanowire array (TiO2 NWs) photoanode in photoelectrochemical cells (PECs) by increasing its supercapacitance. A 2−5 nm carbon layer was coated and the interface supercapacitance increases by about 150 times. This enhances the separation rate of electron-hole pairs by collecting more holes. Meanwhile, it also promotes the water oxidation rate by adsorbing more OH− on its surface. As a result, the photocurrent density of C-TiO2 NWs was about 8 times higher than that of its carbon-free counterpart. This approach of increasing the supercapacitance of photoanodes would be attractive for enhancement of the efficiency of PECs and this work demonstrate the importance of supercapacitance of the interface for PECs. 相似文献
8.
三维多孔石墨烯作为一种优异的石墨烯碳材料, 其独特的多孔结构使得材料在具有较大比表面积的同时还保持着足够高的电子迁移率和机械稳定性, 在电子器件中得到了广泛的应用. 本文介绍的激光诱导石墨烯是一种以一步法直接制备得到的三维网状石墨烯材料, 该技术将三维石墨烯的制备和图案化相结合, 无需进行湿化学反应处理, 制作方法更简便, 材料性能更优异. 目前研究主要集中在通过掺杂提高性能和利用转移法实现不同基底器件的制备. 激光诱导石墨烯自身特有的属性如多孔微纳米结构和大的比表面积等使其在超级电容器和传感器等领域拥有较高的应用价值. 相似文献
9.
近年来, 过渡金属硫族化合物(TMDs)作为一种新兴的二维材料, 因其独特的层状结构及电学特性成为超级电容器电极材料的理想候选者之一. 本文介绍了二维TMDs的常用合成方法, 阐述了钼基、 钨基和钒基等TMDs在超级电容器中的研究进展, 分析了形貌、 尺寸和改性方法等因素对TMDs材料电化学性能的影响, 并对TMDs在超级电容器领域的工业化应用和挑战进行了总结与展望. 相似文献
10.
以萘为碳源, 采用MgO模板诱导耦合KOH裁剪技术制备了相互连接的多孔碳纳米囊(ICNC). 结果表明所制备的ICNC2具有大的比表面积(1811 m2/g)、 高的压实密度(1.38 g/cm3)和微孔孔容含量(58.93%). 在对称的超级电容器(SC)中, ICNC2电极的体积比容在不同电流密度下分别高达420.8 F/cm3(0.069 A/cm3)和315 F/cm3(27.6 A/cm3), 容量保持率为74.82%. 在38 W/L功率密度下, ICNC2基SC的体积能量密度为14.6 W?h/L. 经过20000次循环后, 其体积比容仅衰减1.4%, 库伦效率为99.1%, 为从萘基小分子制备储能用功能碳材料提供了一种可行的方法. 相似文献