The introduction of cobalt element into nickel-organic framework for enhanced supercapacitive performance

Metal-organic frameworks (MOFs) as promising electrodes for supercapacitors are attracting increasing research interest. Herein, we report an effective strategy to improve the electrochemical performance of Ni-MOF for supercapacitor by introducing a secondary Co ion. The Co substitution of Ni in Ni-MOF can improve the intrinsic reactivity and stability. As a result, the bimetallic Co/Ni-MOF-1:15 with an optimal Co/Ni ratio delivers high specific capacitance (359 F/g at 0.5 A/g), good rate performance (81.5% retention at 5 A/g) and cycling stability (81% retention after 5000 cycles). These results demonstrate that the bimetallic synergistic strategy is an effective way to improve the pseudocapacitive performance of MOFs.     

Ni/Co-based metal-organic frameworks as electrode material for high performance supercapacitors

A novel bimetallic Ni/Co-based metal-organic framework (Ni/Co-MOF) was successfully synthesized via a simple solvothermal method, which used as electrode material for high performance supercapacitors.     

Design of hierarchical double-layer NiCo/NiMn-layered double hydroxide nanosheet arrays on Ni foam as electrodes for supercapacitors

Reasonably designing the structure of composite materials and effectively increasing electroactive sites of electrode materials are considered as the promising approaches to enhance the electrochemical performance for supercapacitors. Herein, a double-layer layered double hydroxide nanosheet array grown on Ni foams is constructed through a facile two-step hydrothermal method. The as-prepared double-layer electrode materials including Ni, Co, and Mn elements possess large surface area and porosity; thus, it can increase the contact between electrolytes and the electrode materials, which leads to an increase in electroactive sites and high electrochemical performance. The double-layer electrode shows a high capacitance performance (2950 F/g at 1 A/g) and superior cycling stability (79% retention after 10,000 cycles at 10 A/g). In addition, the asymmetric NiCo/NiMn-LDHs//AC device is fabricated and manifests good capacity with excellent cyclic stability of 82.2% after 10,000 cycles.     

Lignin derived porous carbon with favorable mesoporous contributions for highly efficient ionic liquid-based supercapacitors

Lignin and its derivatives hold great potential in developing high performance porous carbon materials for supercapacitors due to the versatile features of high carbon content, abundant multifunctional groups, low cost, and environmental benefits. Unfortunately, their derived porous carbon generally has the features of unfavorable microporous-dominated morphologies and low specific surface area (SSA) attributed from the highly-branched structure of lignin, which are hardly suitable for the supercapacitors with ionic liquid (IL) electrolyte, leading to poor energy density and rate capability. Herein, porous carbon materials with desirable mesoporous contributions from sodium lignosulphonate are designed via a facile template method. Such rich mesoporisity carbon materials not only possess with three-dimensional interconnected network, large SSA, as well as favorable pore size distribution for accelerated ion and electron mass transfer, but also feature low heteroatom content for high electrochemical stability. Consequently, the optimal electrode exhibits a high capacitance of 166 F/g at 0.5 A/g, superior rate performance (59 Wh/kg at 59 kW/kg), as well as impressive cycle life with good capacitance retention of 93.1% in EMIBF₄ electrolytes. The present work opens a new avenue to design porous carbon materials with high mesopore properties from lignin for effective compatibility with IL electrolyte in high-performance supercapacitors.     

Hierarchical porous nanofibers of carbon@nickel oxide nanoparticles derived from polymer/block copolymer system

The triblock copolymer (PAA-b-PAN-b-PAA) is prepared by reversible addition-fragmentation chain-transfer polymerization, and then blended with polymer (PAN) and metal hydroxide (Ni(OH)₂) as a precursor for heat-treatment. A composite material of hierarchical porous nanofibers and nickel oxide nanoparticles (HPCF@NiO) is prepared by electrospinning combined with high-temperature carbonization. The effects of the ratio of PAA and PAA-b-PAN-b-PAA on the internal structure of nanofibers and their electrochemical properties as positive electrode materials are investigated. The experimental results show that when the ratio of PAA to PAA-b-PAN-b-PAA is 1.3 to 0.4, it has good pore structure and excellent electrochemical performance. At the current density of 1 A/g, the specific capacitance is 188.7 F/g and the potential window is −1 V to 0.37 V. The asymmetric supercapacitor assembled with activated carbon as the negative electrode materials has a specific capacitance of 21.2 F/g in 2 mol/L KOH and a capacitance retention of 85.7% after 12,500 cycles at different current density.     

Hollow polyhedron structure of amorphous Ni-Co-S/Co(OH)_2 for high performance supercapacitors

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.     

N-doped honeycomb-like porous carbon towards high-performance supercapacitor

Biomass-derived porous carbon with developed pore structure is critical to achieving high performance electrode materials. In this work, we report a grape-based honeycomb-like porous carbon (GHPC) prepared by KOH activation and carbonization, followed by N-doping (NGHPC). The obtained NGHPC exhibits a unique honeycomb-like structure with hierarchically interconnected micro/mesopores, and high specific surface area of 1268 m²/g. As a supercapacitor electrode, the NGPHC electrode exhibits a remarkable specific capacitance of 275 F/g at 0.5 A/g in a three-electrode cell. Moreover, the NGHPC//NGHPC symmetric supercapacitor displays a high energy density of 12.6 Wh/kg, and excellent cycling stability of approximately 95.2% capacitance retention after 5000 cycles at 5 A/g. The excellent electrochemical performance of NGHPC is ascribed to its high specific surface area, honeycomb-like structure and high-content of pyrodinic-N (36.29%). It is believed that grape-based carbon materials show great potential as advanced electrode materials for supercapacitors.     

不同Ni含量NiCoAl LDH的制备及CNT/Ni0.3CoAl LDH材料的电化学性能

利用水热法一步合成了不同镍、钴元素比例的镍钴铝层状氢氧化物(NiCoAl LDH),并探究了不同Ni元素含量的NiCoAl LDH的电化学性能,在Ni和Co的物质的量之比为3:7时,Ni_(0.3)CoAl LDH具有最优电化学性能。晶格中部分Ni元素被Co元素代替有利于降低氧化电势,提高材料的化学可逆性。然后通过水热法将CNT与Ni_(0.3)CoAl LDH复合,CNT的复合提高了材料的导电性。CNT/Ni_(0.3)CoAl LDH在1 A·g~(-1)的电流密度下比容量为1 332 F·g~(-1),电流密度为10 A·g~(-1)时比容量保持率为60.4%。在5A·g~(-1)的电流密度下循环3 000圈容量保持率为87.6%。     

介孔材料Co-MCM-41的合成及其吸附脱除各种碱性氮化物

采用水热法合成了MCM-41和不同Co/Si物质的量比的Co-MCM-41介孔材料,并采用XRD、FT-IR和低温氮气吸附-脱附方法对样品进行了表征。FT-IR及XRD表征结果说明,Co原子已经进入了介孔材料的孔壁。合成的MCM-41及Co/Si(物质的量比)为0.18以下的Co-M CM-41都具有六方有序排列的介孔结构。当加入的Co/Si(物质的量比)为0.22时,样品的(100)峰完全消失,不具备六方有序排列的介孔结构,说明以硝酸钴为钴源合成Co-MCM-41的最大Co加入量为Co/Si(物质的量比)为0.18左右。与MCM-41相比,各Co-MCM-41样品的XRD(100)峰随着Co加入量的增加逐渐变宽变弱,比表面积和孔容变小,平均孔径增大。当加入的Co/Si物质的量比大于0.06时,Co-MCM-41的介孔孔道中存在少量聚集态的Co3O4。利用合成的Co-MCM-41吸附脱除氮含量为1737.35μg/g模拟燃料中的碱性氮化物喹啉、苯胺或吡啶,结果表明,所有样品的吸附脱氮效果顺序为苯胺吡啶喹啉。Co-MCM-41(0.06)的吸附容量和氮脱除率明显要高于其他样品,对苯胺、吡啶和喹啉的吸附容量分别为42.17、35.66和29.18 mg(N)/g,去除率分别为82.38%、73.53%和61.11%。添加到模拟燃料中的芳烃化合物萘、苯或甲苯对其吸附脱氮没有影响,表明介孔材料Co-MCM-41对各种含氮化合物的吸附主要是N原子与Co的配位络合吸附,而不是π-π络合作用。采用焙烧或乙醇溶剂洗涤再生后的Co-MCM-41(0.06)恢复了吸附脱氮能力,说明其具有较好的再生性能。     

电化学阴极沉积制备氧化镍/碳纳米管复合电极的准电容特性

A novel type of composite electrode based on multiwalled carbon nanotubes coated with nano nickel oxide particles has been used in supercapacitors. Nickel oxide cathodically deposited from Ni(NO3)2 solution with carbon nanotubes as the matrix exhibited large pseudocapacitance of 25F/g in 6 mol/L KOH. The morphology of composites was examined by scanning electron microscope (SEM). To characterize the CNTs/nickel oxide composite electrode, a charge discharge cycling test for measuring specific capacitance, cyclic voltammetry, and ac impedance test is executed. The nickel oxide composite exhibiting excellent pseudocapacitive behavior(i.e.high reversibility, high specific capacitance, and low self discharge rate) has been demonstrated to be a potential candidate for the application of electrochemical supercapacitors.     

High performance pliable supercapacitor fabricated using activated carbon nanospheres intercalated into boron nitride nanoplates by pulsed laser ablation technique

Pliable supercapacitor, yielding specific capacitance (C_s) and energy density as high as 348 F g⁻¹ and 48.3 Wh Kg⁻¹ respectively was fabricated using modified activated carbon electrodes. The nanospheres of activated carbon (AC) were anchored on the nanoplates of boron nitride (BN) by employing the facile technique of pulsed laser ablation in liquid (PLAL) using 532 nm focused laser beam. Four different variants of electrode materials were synthesized by varying the weight percentage (1%, 3%, 5% and 10%) of BN in AC in the PLAL precursor solution. The morphological characteristics, the elemental composition and the structural analysis of the synthesized electrode materials were studied respectively by FESEM, XPS and XRD. The morphological studies indicated that the PLAL synthesis of the electrode materials resulted in proper intercalation of carbon nanospheres into BN nanoplates, which resulted in the observed enhanced performance of the fabricated supercapacitor. Four supercapacitors in this work were fabricated using the four variants of synthesized electrode materials in conjunction with gel polymer electrolyte (GPE). GPE are well known for their non-corrosive nature and best sealing ability to avoid any leakage that results in increasing the cycle life of the device. The performance of the fabricated supercapacitors was evaluated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) measurement and electrochemical impedance spectroscopy (EIS). The results indicate that the supercapacitor fabricated using 3% BN in AC as electrode material manifested the best specific capacitance and energy density. Also it was found that the supercapacitor maintained 85% of its initial capacitance even after 5000 charge/discharge cycles.     

掺钌氢氧化钴复合材料在碱液中的电化学行为

应用化学共沉淀法制备掺钌氢氧化钴复合材料,X射线衍射(XRD)、扫描电子显微镜(SEM)显示非晶态RuO2颗粒分散在六方晶系Co(OH)2薄片的表面.循环伏安、恒流充放电测试表明,Co/Ru=8/1的复合材料在碱性电解液中具有优良的电容性能和较高的比容量.     

One-pot synthesis of porous nickel–manganese sulfides with tuneable compositions for high-performance energy storage

Mixed-metal compounds, especially for the sulfides, have been investigated as a very attractive type of electroactive materials for supercapacitors. In this work, we demonstrate nickel?manganese (Ni?Mn) sulfides are very attractive for supercapacitors with promising electrochemical performance. The Ni?Mn sulfides with different Ni to Mn ratios have been synthesized via a facile one-pot hydrothermal method, which show a similar structure of interconnected particles and are very porous in microstructure. And then, the Ni?Mn sulfides are investigated by three-electrode measurements and demonstrate strong synergy between Ni and Mn. The Ni?Mn sulfide with a Ni to Mn ratio of 2:1 demonstrates superior performance of 1068?F?g^?1 at 1?A?g^?1. Lastly, The Ni?Mn sulfide with a Ni to Mn ratio of 2:1 are used as positive electrode for two-electrode test, and the asymmetric supercapacitor shows both high energy and power densities combined with excellent cycling stability. Our work demonstrates that the Ni?Mn sulfides are also very electrochemical active for supercapacitors and their performance can be tuned by changing the Ni to Mn ratio.

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Novel Two‐Dimensional Porous Materials for Electrochemical Energy Storage: A Minireview

Two dimensional (2D) porous materials have great potential in electrochemical energy conversion and storage. Over the past five years, our research group has focused on Simple, Mass, Homogeneous and Repeatable Synthesis of various 2D porous materials and their applications for electrochemical energy storage especially for supercapacitors (SCs). During the experimental process, through precisely controlling the experimental parameters, such as reaction species, molar ratio of different ions, concentration, pH value of reaction solution, heating temperature, and reaction time, we have successfully achieved the control of crystal structure, composition, crystallinity, morphology, and size of these 2D porous materials including transition metal oxides (TMOs), transition metal hydroxides (TMHOs), transition metal oxalates (TMOXs), transition metal coordination complexes (TMCCs) and carbon materials, as well as their derivatives and composites. We have also named some of them with CQU‐Chen (CQU is the initialism of Chongqing University, Chen is the last name of Lingyun Chen), such as CQU‐Chen‐Co?O‐1, CQU‐Chen‐Ni?O?H‐1, CQU‐Chen‐Zn?Co?O‐1, CQU‐Chen‐Zn?Co?O‐2, CQU‐Chen‐OA?Co‐2‐1, CQU‐Chen‐Co?OA‐1, CQU‐Chen‐Ni?OA‐1, CQU‐Chen‐Gly?Co‐3‐1, CQU‐Chen‐Gly?Ni‐2‐1, CQU‐Chen‐Gly?Co?Ni‐1, etc. The introduction of 2D porous materials as electrode materials for SCs improves the energy storage performances. These materials provide a large number of active sites for ion adsorption, supply plentiful channels for fast ion transport and boost electrical conductivity and facilitate electron transportation and ion penetration. The unique 2D porous structures review is mainly devoted to the introduction of our contribution in the 2D porous nanostructured materials for SC. Finally, the further directions about the preparation of 2D porous materials and electrochemical energy conversion and storage applications are also included.     

In-situ formed hierarchical transition metal oxide nanoarrays with rich antisite defects and oxygen vacancies for high-rate energy storage devices

Developing transition metal oxides(TMOs) with high energy, power, and long cycle lifetime for electric energy storage devices remains a critical challenge to date. Herein, we demonstrate a facile method that enables in-situ transformation of nickel cobalt oxide nanowire arrays(Ni Co O NWA) into hierarchical nanowire-nanosheet arrays(ac-Ni Co O NWSA) for enhanced energy storage properties. More specifically,the method leads to formation of atomically thin nanosheets(only 2.0 nm) and creates abund...     

An Advanced NiCoFeO/Polyaniline Composite for High‐Performance Supercapacitors

To reduce the charge‐transfer resistance of supercapacitors and achieve faster reversible redox reactions, ternary Ni‐Co‐Fe layered double hydroxide was prepared by using the urea method and then calcined to give NiCoFe oxide (NiCoFeO). To enhance conductivity, a polyaniline (PANI) conductive layer was assembled on the surface of the NiCoFeO particles by in situ oxidative polymerization of aniline monomers. The as‐prepared NiCoFeO/PANI composite was successful employed as a supercapacitor electrode. It was found that the NiCoFeO/PANI composite displayed good cycling stability, with a capacity loss of only 29.54 % after 5000 cycles. Furthermore, the NiCoFeO/PANI composite also exhibited excellent supercapacitor performance, with a high specific capacity of 843 F g^?1 at a current density of 2 A g^?1, whereas NiCoFeO showed a specific capacity of only 478 F g^?1. This result was attributed to the synergistic effect between NiCoFeO and PANI. The facile synthesis strategy and excellent electrochemical performance suggest that NiCoFeO/PANI is a promising economical electrode material for applications in supercapacitors.     

Preparation,characterization and hydrodesulfurization performances of Co-Ni_2P/SBA-15 catalysts

A series of Co-Ni2P/SBA-15 catalysts with various Co contents, Ni2P contents and P/Ni molar ratios were prepared by impregnating nickel nitrate, diammonium hydrogen phosphate, and then cobalt nitrate into SBA-15 support followed by temperature-programmed reduction in a H2 flow. The catalyst structure was characterized by X-ray diffraction(XRD), high resolution-transmission electron microscopy(HR-TEM)and N2adsorption-desorption techniques and their catalytic performance of the hydrodesulfurization(HDS) of dibenzothiophene(DBT) was evaluated. The effects of Co contents, Ni2 P contents and P/Ni molar ratios on the catalyst structure and HDS of DBT over the Co-Ni2P/SBA-15 catalyst were investigated. The results indicated that the mesoporous structure was mainly maintained and the nickel phosphides were well dispersed in all of the characterized catalysts. The 4Co-25Ni2P/SBA-15(P/Ni = 0.8) catalyst with the Co and Ni2 P contents of 4 wt% and25 wt%, respectively, and the P/Ni molar ratio of 0.8 showed the highest catalytic performance for HDS of DBT. Under the reaction conditions of 380?C and 3.0 MPa, the DBT conversion can reach 99.62%. The HDS of DBT proceeded mainly via the direct desulfurization(DDS)pathway with biphenyl(BP) as the dominant product on all of the catalysts and the BP selectivity was slightly enhanced after the introduction of Co promoters.     

Ni Foam-Supported Tin Oxide Nanowall Array: An Integrated Supercapacitor Anode

A novel product consisting of a homogeneous tin oxide nanowall array with abundant oxygen deficiencies and partial Ni-Sn alloying onto a Ni foam substrate was successfully prepared using a facile solvothermal synthesis process with subsequent thermal treatment in a reductive atmosphere. Such a product could be directly used as integrated anodes for supercapacitors, which showed outstanding electrochemical properties with a maximum specific capacitance of 31.50 mAh·g⁻¹ at 0.1 A·g⁻¹, as well as good cycling performance, with a 1.35-fold increase in capacitance after 10,000 cycles. An asymmetric supercapacitor composed of the obtained product as the anode and activated carbon as the cathode was shown to achieve a high potential window of 1.4 V. The excellent electrochemical performance of the obtained product is mainly ascribed to the hierarchical structure provided by the integrated, vertically grown nanowall array on 3D Ni foam, the existence of oxygen deficiency and the formation of Ni-Sn alloys in the nanostructures. This work provides a general strategy for preparing other high-performance metal oxide electrodes for electrochemical applications.     

LiNi_(0.85)Co_(0.15)O_2合成和结构与电化学性能关系

介绍了一种以LiOH·H_2O, Co_2O_3和Ni_2O_3为原料通过高温法合成LiNi_(0. 85)Co_(0.15)O_2的方法，通过XRD和电化学测试对制得的产物进行了表征，讨论了 合成条件对产物结构的影响以及结构与电化学性能之间的关系。实验结果表明，合 成反应温度、Li/Ni/Co摩尔比对LiNi_(0.85)Co_(0.15)O_2的结构和电化学性能有 较大的影响，合成出具有电化学活性的LiNi_(0.85)Co_(0.15)O_2需要严格控制反 应条件。本文合成出具有高度结晶层状结构的LiNi_(0.85)Co_(0.15)O_2, Rietveld精化结果表明a = 0.2874 nm, c = 1.4229 nm，最大晶胞体积V = 0. 10180 nm~3，其首次放电容量可达197 mA·h/g, 15次循环后，其放电容量仍在 180 mA·h/g以上。     

General Formation of MxCo3−xS4 (M=Ni,Mn, Zn) Hollow Tubular Structures for Hybrid Supercapacitors

A simple and versatile method for general synthesis of uniform one‐dimensional (1D) M_xCo_3?xS₄ (M=Ni, Mn, Zn) hollow tubular structures (HTSs), using soft polymeric nanofibers as a template, is described. Fibrous core–shell polymer@M‐Co acetate hydroxide precursors with a controllable molar ratio of M/Co are first prepared, followed by a sulfidation process to obtain core–shell polymer@M_xCo_3?xS₄ composite nanofibers. The as‐made M_xCo_3?xS₄ HTSs have a high surface area and exhibit exceptional electrochemical performance as electrode materials for hybrid supercapacitors. For example, the MnCo₂S₄ HTS electrode can deliver specific capacitance of 1094 F g^?1 at 10 A g^?1, and the cycling stability is remarkable, with only about 6 % loss over 20 000 cycles.