镍掺杂花状纳米碳片的制备及其在超级电容器中的应用

本文通过溶剂热法"一锅"制备了镍掺杂的花状纳米碳片(Ni/FCNAs)。借助X射线衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对该复合材料的表面形貌和结构进行了分析。循环伏安和恒流充/放电测试结果表明,Ni/FCNAs具有较大的比电容值且电化学稳定性良好。在电流密度为0.1 A.g-1时,Ni/FCNAs电极的比电容可达176 F.g-1。本文同时也提出了Ni/FCNAs可能的形成机理。     

氮掺杂碳片的模板诱导制备及其在超级电容器中的应用

兼具有优良的导电能力,高的比表面积和极佳的化学/机械稳定性,具有二维形貌的纳米碳材料近年来逐渐成为超级电容器电极材料的研究热点. 我们在此首次报道一种模板诱导方法以制备具有规整片状形貌的氮掺杂碳材料. 我们将作为硬模板的片状镁铝双金属氢氧化物与熔融的邻苯二胺混合后加入三氯化铁催化剂,进而通过加热使邻苯二胺聚合并碳化,随后刻蚀除去其中的氧化物成分即可以得到具有规整六边形片状氮掺杂碳材料. 通过改变碳化时的温度,可以有效的调节利用该方法所得到的氮掺杂碳片的形貌、结构、石墨化程度、氮含量以及比表面积. 更重要的是这些氮掺杂碳片在用作超级电容器电极材料时体现出优异的电化学性能,在0.5 A·g^-1的电流密度下其比容量可以达到290.0 F·g^-1的. 在1 A·g^-1的电流密度下经过10000周循环测试后,其容量仍然可以达到初始值83%.     

SnO_2/石墨纳米片复合电极及其在超级电容器中的应用

在电场的作用下对石墨棒进行电化学剥离,使其表面形成相互平行排列,且垂直于石墨棒基底的二维(2D)石墨纳米片阵列(GNSA).然后通过阴极还原电沉积法制备Sn O2/石墨纳米片阵列(Sn O2/GNSA)复合电极.采用场发射扫描电镜(FE-SEM)、X射线衍射(XRD)和傅里叶变换红外(FT-IR)光谱对其形貌和结构进行了表征.电化学测试表明该复合电极具有优异的超电容性能,在0.5 mol·L-1Li NO3电解质中,扫描速率为5 m V·s-1,电位窗口为1.4 V时,比电容达4015 F·m-2.由Sn O2/GNSA复合电极和相同电解质组装成的对称型超级电容器,在扫描速率为5 m V·s-1时,其电位窗口可增至1.8 V,能量密度达到0.41 Wh·m-2,循环5000圈后其比电容仍保持为初始比电容的81%.     

超级电容器用相互连接的类石墨烯纳米片

采用氧化镁模板耦合原位氢氧化钾活化法制备了超级电容器用煤焦油基相互连接的类石墨烯纳米片(IGNSs)。所制备的IGNS具有高达2887 m~2·g~(-1)的比表面积和大量的分级短孔。当作为超级电容器的电极材料时,在6 mol·L~(-1) KOH电解液中,于0.05 A·g~(-1)的电流密度下,IGNS显示出313 F·g~(-1)的高比容;在20 A·g~(-1)的电流密度下,IGNS的比电容为261F·g~(-1),显示了好的倍率性能;经过10000次循环测试后,其容量保持率为92.7%,展现了优异的循环稳定性。这一工作为从芳烃分子大规模生产高性能储能用类石墨烯纳米片提供了一种简单的方法。     

SnO2/石墨纳米片复合电极及其在超级电容器中的应用

在电场的作用下对石墨棒进行电化学剥离, 使其表面形成相互平行排列, 且垂直于石墨棒基底的二维(2D)石墨纳米片阵列(GNSA). 然后通过阴极还原电沉积法制备SnO₂/石墨纳米片阵列(SnO₂/GNSA)复合电极.采用场发射扫描电镜(FE-SEM)、X射线衍射(XRD)和傅里叶变换红外(FT-IR)光谱对其形貌和结构进行了表征.电化学测试表明该复合电极具有优异的超电容性能, 在0.5 mol·L^-1 LiNO₃电解质中, 扫描速率为5 mV·s^-1, 电位窗口为1.4 V时, 比电容达4015 F·m^-2. 由SnO₂/GNSA复合电极和相同电解质组装成的对称型超级电容器, 在扫描速率为5 mV·s^-1时, 其电位窗口可增至1.8 V, 能量密度达到0.41 Wh·m^-2, 循环5000 圈后其比电容仍保持为初始比电容的81%.     

双金属离子调控型镍钴氧化物纳米片用于非对称超级电容器

通过水热-煅烧两步法制备了系列镍钴氧化物（NCO）纳米片。通过改变前驱体溶液中的镍、钴离子物质的量之比,进而调控NCO纳米片中的过渡金属离子比例。NCO纳米片的晶相、形貌和结构利用X射线衍射、扫描电子显微镜和X射线光电子能谱表征。此外,对NCO纳米片的电化学性能进行测试。结果表明,NCO-2（Ni_1.95Co₁O_x）纳米片在0.5 A·g^-1电流密度下,比电容为1 096.88 F·g^-1,且经过5 000次循环后具有78.26%的循环稳定性。以NCO-2为正极、活性碳为负极构成的非对称超级电容器,在功率密度为576 W·kg^-1时,能量密度为57.70 Wh·kg^-1。     

双金属离子调控型镍钴氧化物纳米片用于非对称超级电容器

通过水热-煅烧两步法制备了系列镍钴氧化物(NCO)纳米片。通过改变前驱体溶液中的镍、钴离子物质的量之比,进而调控NCO纳米片中的过渡金属离子比例。NCO纳米片的晶相、形貌和结构利用X射线衍射、扫描电子显微镜和X射线光电子能谱表征。此外,对NCO纳米片的电化学性能进行测试。结果表明,NCO-2(Ni_1.95Co₁O_x)纳米片在0.5 A·g^-1电流密度下,比电容为1 096.88 F·g^-1,且经过5 000次循环后具有78.26%的循环稳定性。以NCO-2为正极、活性碳为负极构成的非对称超级电容器,在功率密度为576 W·kg^-1时,能量密度为57.70 Wh·kg^-1。     

自掺杂氮多孔交联碳纳米片在超级电容器中的应用

自掺杂氮的多孔交联碳纳米片（N-ICNs）是将蒲公英种子通过一步活化碳化法制备的.蒲公英种子本身富含氮,不需要进行额外的掺杂处理,可以作为理想的碳前驱体.通过X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）对所制备的碳材料的微观形貌和组成成分进行了表征.基于高含氮量（2.88%）,N-ICNs在1 A·g^-1下具有337 F·g^-1的比电容和优异的倍率性能.此外,由N-ICNs组合成的对称型超级电容器在操作电压范围为0~2 V时具有很高的能量密度（25.3 Wh·kg^-1）和功率密度（900 W·kg^-1）,并且在循环10000次后仍具有98%的电容保持率.因此,N-ICNs将是一种非常理想的电极材料.     

MnO2/煤基碳纳米纤维的制备及其在柔性超级电容器中的应用

采用静电纺丝技术制备了柔性煤基碳纳米纤维(CBCNFs)。利用低温等离子体技术对CBCNFs进行改性,并将改性后的CBCNFs作为还原剂与KMn O4反应,以实现Mn O2的原位还原负载制备CBCNFs/Mn O2复合材料。通过X射线衍射、扫描电镜和透射电镜等手段对复合材料的结构与形貌进行了表征;另外,研究了其作为柔性超级电容器电极材料的性能。结果表明,KMn O4∶CBCNFs=2∶1(质量比)条件下制备的复合材料(CBCNFs/Mn O2-2)具有良好的电化学性能。在0.1A·g-1电流密度下,CBCNFs/Mn O2-2的比电容高达118F·g-1,为CBCNFs比电容(26F·g-1)的4.5倍,在1A·g-1电流密度下,循环1000次后比容量保持率为97%,表现出良好的循环稳定性。     

基于NiCo2O4纳米片电极的非对称混合电容器

The looming global energy crisis and ever-increasing energy demands have catalyzed the development of renewable energy storage systems. In this regard, supercapacitors (SCs) have attracted widespread attention because of their advantageous attributes such as high power density, excellent cycle stability, and environmental friendliness. However, SCs exhibit low energy density and it is important to optimize electrode materials to improve the overall performance of these devices. Among the various electrode materials available, spinel nickel cobaltate (NiCo₂O₄) is particularly interesting because of its excellent theoretical capacitance. Based on the understanding that the performances of the electrode materials strongly depend on their morphologies and structures, in this study, we successfully synthesized NiCo₂O₄ nanosheets on Ni foam via a simple hydrothermal route followed by calcination. The structures and morphologies of the as-synthesized products were characterized by X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller (BET) surface area analysis, and the results showed that they were uniformly distributed on the Ni foam support. The surface chemical states of the elements in the samples were identified by X-ray photoelectron spectroscopy. The as-synthesized NiCo₂O₄ products were then tested as cathode materials for supercapacitors in a traditional three-electrode system. The electrochemical performances of the NiCo₂O₄ electrode materials were studied and the area capacitance was found to be 1.26 C·cm^-2 at a current density of 1 mA·cm^-2. Furthermore, outstanding cycling stability with 97.6% retention of the initial discharge capacitance after 10000 cycles and excellent rate performance (67.5% capacitance retention with the current density from 1 to 14 mA·cm^-2) were achieved. It was found that the Ni foam supporting the NiCo₂O₄ nanosheets increased the conductivity of the electrode materials. However, it is worth noting that the contribution of nickel foam to the areal capacitance of the electrode materials was almost zero during the charge and discharge processes. To further investigate the practical application of the as-synthesized NiCo₂O₄ nanosheets-based electrode, a device was assembled with the as-prepared samples as the positive electrode and active carbon (AC) as the negative electrode. The assembled supercapacitor showed energy densities of 0.14 and 0.09 Wh·cm^-3 at 1.56 and 4.5 W·cm^-3, respectively. Furthermore, it was able to maintain 95% of its initial specific capacitance after 10000 cycles. The excellent electrochemical performance of the NiCo₂O₄ nanosheets could be ascribed to their unique spatial structure composed of interconnected ultrathin nanosheets, which facilitated electron transportation and ion penetration, suggesting their potential applications as electrode materials for high performance supercapacitors. The present synthetic route can be extended to other ternary transition metal oxides/sulfides for future energy storage devices and systems.     

Flexible asymmetric supercapacitor with high energy density based on optimized MnO2 cathode and Fe2O3 anode

A flexible asymmetric supercapacitor is assembled using MnO₂ nanosheets/carbon fabric and Fe₂O₃/carbon fabric electrodes. By optimizing the reaction condition of the two electrodes, the device shows high energy densities and excellent flexibility.     

A novel polyaniline/mesoporous carbon nano-composite electrode for asymmetric supercapacitor

<正>A novel nano-composite of polyaniline/mesoporous carbon(PANI/CMK-3) was prepared with mesoporous carbon(CMK-3) serving as the support.Electrochemical asymmetric capacitors have been successfully designed by using PANI/CMK-3 composite and CMK-3 as positive and negative electrode,respectively.The results showed that the discharge capacity of the asymmetric capacitor could reach 87.4 F/g under the current density of 5 mA/cm~2 and cell voltage of 1.4 V.The energy density of the asymmetric capacitor was up to 23.8 Wh/kg with a power density of 206 W/kg.Furthermore,PANI/CMK-3-CMK-3 asymmetric capacitor using this PANI/CMK-3 nano-composite could be activated quickly and possess high charge-discharge efficiency.     

CoNi2S4上电沉积NiS用于柔性固态非对称超级电容器

采用一种在CoNi2S4上电沉积NiS的有效方法来改善钴/镍硫化物的性能。CoNi2S4@NiS电极材料在1 A·g^-1时比电容达到1433 F·g^-1,并具有很好的倍率性能。CoNi2S4@NiS和还原氧化石墨烯组装成的柔性固态非对称超级电容器的能量密度在功率密度为800 W·kg^-1时达到36.6 Wh·kg^-1,并且在10000次充放电后表现出良好的循环性能,循环保持率达87.8%。     

Mo掺杂NiMnSe2的制备及其超级电容器性能

成分和结构是影响多元过渡金属硒化物电化学活性的关键因素。适当掺杂其他金属元素可以有效提高电极材料的电化学性能。通过简单的一步水热法,在泡沫镍上制备出了一种无黏结剂的Mo掺杂NiMnSe₂(记作Ni_0.8Mo_0.2MnSe₂)。Mo的少量掺杂为电极材料提供了丰富的反应活性位点,大大提高了NiMnSe₂的电化学性能。在1 A·g^-1时,Ni_0.8Mo_0.2MnSe₂的比容量达到1 404.0 F·g^-1。掺杂Mo显著降低了NiMnSe₂的电荷转移电阻和扩散电阻。组装的混合超级电容器Ni_0.8Mo_0.2MnSe₂//AC (活性炭)比容量达到81.6 F·g^-1,且倍率性能优异。在2 A·g-1下连续充放电10 000周,容量保持率为95.8%,表现出超高的循环稳定性。混合超级电容器Ni_0.8Mo_0.2MnSe₂//AC在376.6 W·kg^-1的功率密度下,能量密度达25.5 Wh·kg^-1,高于NiMnSe2//AC (17.3 Wh·kg^-1)。     

Mo掺杂NiMnSe2的制备及其超级电容器性能

成分和结构是影响多元过渡金属硒化物电化学活性的关键因素。适当掺杂其他金属元素可以有效提高电极材料的电化学性能。通过简单的一步水热法,在泡沫镍上制备出了一种无黏结剂的Mo掺杂NiMnSe₂(记作Ni_0.8Mo_0.2MnSe₂)。Mo的少量掺杂为电极材料提供了丰富的反应活性位点,大大提高了NiMnSe₂的电化学性能。在1 A·g^-1时,Ni_0.8Mo_0.2MnSe₂的比容量达到1 404.0 F·g^-1。掺杂Mo显著降低了NiMnSe₂的电荷转移电阻和扩散电阻。组装的混合超级电容器Ni_0.8Mo_0.2MnSe₂//AC (活性炭)比容量达到81.6 F·g^-1,且倍率性能优异。在2 A·g^-1下连续充放电10 000周,容量保持率为95.8%,表现出超高的循环稳定性。混合超级电容器Ni_0.8Mo_0.2MnSe₂//AC在376.6 W·kg^-1的功率密度下,能量密度达25.5 Wh·kg^-1,高于NiMnSe₂//AC (17.3 Wh·kg^-1)。     

Mo掺杂NiMnSe2的制备及其超级电容器性能

成分和结构是影响多元过渡金属硒化物电化学活性的关键因素。适当掺杂其他金属元素可以有效提高电极材料的电化学性能。通过简单的一步水热法,在泡沫镍上制备出了一种无黏结剂的Mo掺杂NiMnSe₂(记作Ni_0.8Mo_0.2MnSe₂)。Mo的少量掺杂为电极材料提供了丰富的反应活性位点,大大提高了NiMnSe₂的电化学性能。在1 A·g^-1时,Ni_0.8Mo_0.2MnSe₂的比容量达到1 404.0 F·g^-1。掺杂Mo显著降低了NiMnSe₂的电荷转移电阻和扩散电阻。组装的混合超级电容器Ni_0.8Mo_0.2MnSe₂//AC (活性炭)比容量达到81.6 F·g^-1,且倍率性能优异。在2 A·g^-1下连续充放电10 000周,容量保持率为95.8%,表现出超高的循环稳定性。混合超级电容器Ni_0.8Mo_0.2MnSe₂//AC在376.6 W·kg^-1的功率密度下,能量密度达25.5 Wh·kg^-1,高于NiMnSe₂//AC (17.3 Wh·kg^-1)。     

Facile hydrothermal synthesis of zinc sulfide nanowires for high-performance asymmetric supercapacitor

A facile, single-step hydrothermal route is followed to prepare ZnS nanowires with large aspect ratios. The obtained ZnS nanowires deposited on nickel foam (ZnS/Ni-foam) exhibit a specific capacitance of 781 F/g at a current density of 0.5 A/g. An asymmetric supercapacitor fabricated from ZnS/Ni-foam as a positive electrode and jute derived activated carbon coated on Ni-foam (JAC/Ni-foam) as a negative electrode attains a high specific capacitance of 573 F/g at a current density of 0.5 A/g, with an accompanying high energy density of 51 Wh/kg at a power density of 200 W/kg in an extensive operating potential window of 1.2 V. In addition, the ZnS//JAC asymmetric supercapacitor reveals long-term cyclic stability, after 10,000 GCD cycles the device sustain around ～87 % of the initial specific capacitance. These results shed enlighten a new opportunity for promising electrode materials in supercapacitors.     

构建NiS2/MoSe2 S型异质结高效光催化产氢

S-scheme heterojunction is a major breakthrough in the field of photocatalysis. In this study, NiS₂ and MoSe₂ were prepared by a typical solvothermal method, and compounded by an in situ growth method to construct an S-scheme heterojunction. The obtained composite showed excellent performance in photocatalytic hydrogen evolution; the hydrogen production rate was approximately 7 mmol·h^-1·g^-1, which was 2.05 times and 2.44 times those of pure NiS₂ and MoSe₂, respectively. Through a series of characterizations, it was found that NiS₂ and MoSe₂ coupling can enhance the light absorption intensity, which is vital for the light reaction system. The efficiency of electron-hole pair separation is also among the important factors restricting photocatalytic reactions. Compared with pure NiS₂ and MoSe₂, NiS₂/MoSe₂ exhibited a higher photocurrent density, lower cathode current, and lower electrochemical impedance, which proves that the NiS₂/MoSe₂ complex can effectively promote photogenerated electron transfer. Simultaneously, the lower emission intensity of fluorescence indicated effective inhibition of electron-hole recombination in the NiS₂/MoSe₂ complex, which is favorable for the photocatalytic hydrogen evolution reaction. Further, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that MoSe₂ is an amorphous sample surrounded by the NiS₂ nanomicrosphere, which greatly increased the contact area between the two, thus increasing the active site of the reaction. Secondly, as a photosensitizer, Eosin Y (EY) effectively enhanced the absorption of light by the catalyst in the photoreaction system. Meanwhile, during sensitization, electrons were provided to the catalyst, which effectively improved the photocatalytic reaction efficiency. The establishment of S-scheme heterojunctions contributed to improving the redox capacity of the reaction system and was the most important link in the photocatalytic hydrogen reduction of aquatic products. It was also the main reason for the improvement of the hydrogen evolution effect in this study. The locations of the conduction band and valence band of NiS₂ and MoSe₂ were determined by Mott-Schottky plots and photon energy curves, and further proved the establishment of the S-scheme heterojunction. This work provides a new reference for studying the S-scheme heterojunction to effectively improve the photocatalytic hydrogen production efficiency.      

超级电容器电极材料MnO_2纳米棒的制备及其电化学性能(英文)

以洋葱碳为还原剂,KMnO4为氧化剂,稀硫酸溶液为溶剂,采用水热法一步制备MnO2纳米棒.利用X射线衍射仪和透射电子显微镜分析了MnO2纳米棒的物相、结构、形貌;将MnO2纳米棒作为电极材料组装了超级电容器,采用电池测试系统测定了超级电容器的电化学性能.结果表明,所得到的产物为α-MnO2,其直径为5~10nm,长度为50~100nm;以MnO2纳米棒作为电极材料组装的超级电容器具有较高的比容量和稳定性,有望在超级电容器的研究和应用中得到推广.