Achieving high electrode specific capacitance with materials of low mass specific capacitance: Potentiostatically grown thick micro-nanoporous PEDOT films

Electrode materials for supercapacitors are at present commonly evaluated and selected by their mass specific capacitance (C_M, F g⁻¹). However, using only this parameter may be a misleading practice because the electrode capacitance also depends on kinetics, and may not increase simply by increasing material mass. It is therefore important to complement C_M by the practically accessible electrode specific capacitance (C_E, F cm⁻²) in material selection. Poly[3,4-ethylene-dioxythiophene] (PEDOT) has a mass specific capacitance lower than other common conducting polymers, e.g. polyaniline. However, as demonstrated in this communication, this polymer can be potentiostatically grown to very thick films (up to 0.5 mm) that were porous at both micro- and nanometer scales. Measured by both cyclic voltammetry and electrochemical impedance spectrometry, these thick PEDOT films exhibited electrode specific capacitance (C_E, F cm⁻²) increasing linearly with the film deposition charge, approaching 5 F cm⁻², which is currently the highest amongst all reported materials.     

A Novel Electrochemical Sensor Based on Poly(1,5-diaminonaphthalene) and Poly(1,2-diaminoanthraquinone) Core-shell Composite Electrodes for Effective Voltammetric Determination of Nitrite

In this article, poly(1,2-diaminoanthraquinone) (pDAAQ) and poly(1,5-diaminonaphthalene) (pDAN) were electrochemically deposited layer by layer on a glassy carbon electrode (GCE) to generate pDAAQ/pDAN@GCE and pDAN/pDAAQ@GCE composite electrodes, respectively. The morphology and characteristics of the modified electrodes were investigated via electrochemical impedance spectroscopy)EIS), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy)SEM). The obtained results reveal the outstanding performance of the pDAN/pDAAQ@GCE electrode for electrochemical nitrite sensing where pDAAQ plays a vital role as the inner layer. Cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV) measurements revealed that the oxidation peak current of nitrite was proportional to its concentration. The best LSV results were obtained in a concentration range of 10–150 μM, with a limit of detection of 1.2 μM. Furthermore, the pDAN/pDAAQ@GCE composite electrode was used to determine nitrite ions in real water samples with good results.     

Highly mesoporous structure nickel cobalt oxides with an ultra-high specific surface area for supercapacitor electrode materials

Journal of Solid State Electrochemistry - Highly mesoporous structure nickel cobalt oxides with an ultra-high specific surface area are synthesized through a sol–gel method by using silica...     

Preparation of Ni/poly(1,5-diaminonaphthalene)-modified carbon paste electrode; application in electrocatalytic oxidation of formaldehyde for fuel cells

This paper deals with electrochemical oxidation of formaldehyde in alkaline solution with a new electrocatalytic system composed of carbon paste electrode coated with poly(1,5-diaminonaphthalene) (P-1,5-DAN) film containing incorporated Ni(II)/Ni(III) redox ions. The modifier layer of (P-1,5-DAN-Ni)(OH)₂ at the electrode surface acts as a catalyst for the oxidation of formaldehyde in 0.1-M NaOH solution. Cyclic voltammetric and chronoamperometric experiments showed that the formaldehyde can be oxidized at the surface of Ni/P-1,5-DAN-modified carbon paste electrode. In cyclic voltammetry studies, the peak current of the oxidation of nickel hydroxide in the presence of formaldehyde increases and is followed by a decrease in the corresponding cathodic current. The rate constant (k) for the chemical reaction between the formaldehyde and nickel hydroxide has been evaluated by chronoamperometry method. This polymeric-modified electrode can oxidize the formaldehyde with high current density (over 7 mA cm⁻²). Thus, it can be a candidate as an anode for fuel cell applications.     

Simultaneous determination of ascorbic acid,uric acid and dopamine at modified electrode based on hybrid nickel hexacyanoferrate/poly(1,5-diaminonaphthalene)

A novel modified electrode was fabricated by a mixed-valent nickel hexacyanoferrate (NiHCF) and poly 1,5-diaminonaphthalene (PDAN) hybrid at glassy carbon (GC) electrode. The obtained NiHCF/PDAN/GC modified electrode was characterized using cyclic voltammetry (CV) technique and scanning electron microscope (SEM). This electrode showed excellent catalytic properties toward the electrooxidation of ascorbic acid (A.A), dopamine (D.A) and uric acid (U.A) in 0.1 M NaCl solution using CV and square wave voltammetry (SWV) techniques. The NiHCF/PDAN/GC modified electrode exhibits high sensitivity, selectivity and stability making it a suitable sensor for the simultaneous detection of A.A, U.A and D.A in single and ternary mixture solutions. Different analytical parameters such as low detection limit (LOD), low quantification limit, correlation coefficient (R) and linear dynamic range were reported and discussed. The NiHCF/PDAN/GC modified electrode exhibits linear responses to A.A, D.A and U.A in the range 600–1000, 600–1000 and 600–1000 µM, respectively. The LOD for A.A, D.A and U.A were 0.036, 0.034 and 0.037 µM, respectively. The analytical behavior of this sensor had been evaluated for the detection of A.A and U.A in human serum and urine samples with satisfactory results.     

Electrochemical modification of a carbon paste electrode with poly (1,5-diaminonaphthalene) and copper-cobalt nanostructures for the determination of thioctic acid in real samples

This study used square-wave voltammetry and cyclic voltammetry to investigate the electrochemical oxidation of Thioctic Acid (TA) on a Carbon Paste Electrode (CPE) modified with copper-cobalt nanostructures and poly (1,5-Diaminonaphthalene). The voltammetric sensor was sensitive to the oxidation of TA. In addition, we optimized the effects of multiple cycles of deposition of Cu-Co nanostructures, and electro-polymerization of monomer 1,5-DAN, scan rate, and pH. The sensor showed good identification capabilities for TA. The linear responses obtained ranged from 0.6 μM to 150 μM with a detection limit of 0.48 μM for the modified CPE. The adsorption process controlled the oxidation of TA. We used the proposed sensor and method to determine TA in real samples.     

Poly(2,3-diaminonaphthalene) microspheres as a novel quencher for fluorescence-enhanced nucleic acid detection

In this Communication, we report on the first preparation of conjugation polymer poly(2,3-diaminonaphthalene) (PDAN) microspheres via chemical oxidation polymerization of 2,3-diaminonaphthalene (DAN) monomers by ammonium persulfate (APS) at room temperature. We further demonstrate the use of PDAN microspheres as a novel quencher for fluorescence-enhanced nucleic acid detection.     

Electrocatalytic oxidation of methanol onto platinum particles decorated nanostructured poly (1,5-diaminonaphthalene) film

In this work, platinum particles decorated nanostructured poly (1,5-diaminonaphthalene) modified glassy carbon electrode (Pt/Nano-PDAN/MGCE) is prepared. The composite catalysts are characterized by scanning electron microscopy, energy dispersive spectroscopy, and electrochemical methods. The electrochemical methanol oxidation reaction is studied at the surface of this modified electrode. At same Pt loading, the Pt/Nano-PDAN/MGCE can act as higher efficient catalyst for methanol oxidation than that Pt/MGCE. Then, the influence of some parameters such as potential scan rates, switching potential, and methanol concentration on its oxidation as well as long-term stability of the modified electrode have studied by electrochemical methods. Also, ability of the modified electrode toward electrocatalytic oxidation of formaldehyde as an intermediate in methanol oxidation has been investigated.     

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.     

Activated carbon and its hybrid composites with manganese (IV) oxide as effectual electrode materials for high performance supercapacitor

Waste wood-dust of Dalbergia sisoo (Sisau) is presented, as a novel, low-cost, renewable, and sustainable source of agro-waste for the production of a highly porous activated carbon electrodes (Ds-electrodes) for supercapacitor. Ds-electrode was initially tested as supercapacitor electrode, which showed a lesser specific capacitance of 104.4 Fg^?1. Therefore, hybrid-composite-electrodes (HCEs) were fabricated by adopting the nanostructured “manganese IV oxide (MnO₂)-activated carbon (Ds) composite” in various ratios as the core electrode materials. The HCEs was prepared via a simple facile mechanical mixing method and polyvinylidine fluoride (PVDF) polymeric solution was used as the electrode material binder. The experimental results showed that the 1:1 Ds: MnO₂ composite displayed highest specific capacitance of 300.2 Fg^?1, capacity retention of 96.3 % after 1000 cycles, 16.3 WhKg^?1 of specific energy density at power density of 148.2 WKg^?1 and low equivalent series resistance (ESR) value of 0.41 Ω at equivalent (1:1, Ds:MnO₂) loading of MnO₂ to Ds. It is clear that the equivalent (1:1) concentration of MnO₂ has improved the capacitive performance of the composite via pseudocapacitance charge storage mechanism as well as the enhancement on the specific surface area of the electrode. However, further increasing of the MnO₂ content (1:2, Ds:MnO₂) in the electrode was found to distort the capacitive performances and deteriorate the specific surface area of the electrode, mainly due to the aggregation of the MnO₂ particles within the composite.     

New electrode materials for lithium-ion batteries (Review)

The main principles of operation of modern lithium-ion batteries and the modern trends in development of new-generation batteries are described.     

Poly(aniline) solid contact ion selective electrode for udenafil

Udenafil is an oral agent for treating male erectile dysfunction. The poly(aniline) solid contact selective electrodes for udenafil have been fabricated from PVC cocktail solutions with three ion selective ion pairs. This solid contact electrode contains three layers of Pt/electro-conductive poly(aniline) polymer/PVC film with an ionophore with a thickness of 2.5 ± 0.1 mm. We compared the slopes of EMF responses and the response range of a solid contact electrode based on Udenafil-TmCIPB ion pair with those based on Udenafil-PMA and Udenafil-TPB ion pairs and showed that the response slopes were influenced by plasticizers. The EMF response slopes of Udenafil-TmCIPB-based solid contact electrodes equalled 58.0 mV/decade (at 20 ± 0.2°C) and their linear response dynamic ranges were 1.0 × 10⁻²∼1.0 × 10^−5.85 M (r ² = 0.9984). When electrodes with 6 different plasticizers based on Udenafil-TmCIPB were compared, as the dielectric constant of PVC plasticizer increased, so was the response slope at the same time. Having applied the electrodes to artificial serum directly, we could get same satisfactory results [Nernstian slope: 60.3 mV/decade, dynamic range: 1.0 × 10⁻²∼1.0 × 10^−5.78 M (r ² = 0.9978) in artificial serum]. Solid contact electrodes with Udenafil-TmCIPB have shown the best selectivity, reproducibility of EMF, long-term stability, and short response time (< 20 s).     

Poly(vinyl chloride) membrane electrode for the determination of verapamil

A verapamil-PVC membrane ion-selective electrode based on the verapamil-reineckate ion pair was prepared with dibutyl phthalate as a plasticizer. The electrode exhibited a linear response with a Nernstian slope (52.8 mV decade^?1 at 20° C) for verapamil concentrations of 10^?5?10^?2M over the pH range 3–7. The electrode also exhibited very good selectivity for verapamil with respect to various inorganic and organic cations. Gran II linear titration and potentiometric titration were used to determine verapamil in pure solution, with an average recovery of 99.3% and a relative standard deviation of 0.4%.     

聚1,8-萘二胺修饰玻碳电极测定痕量汞

采用电化学聚合的方法制备了聚1,8-萘二胺修饰玻碳电极,建立了吸附富集-阳极溶出伏安法测定痕量Hg2+的新方法.优化了各种实验参数(如富集底液的pH,富集时间等),并考察了其它离子的干扰.在最佳实验条件下,Hg2+在0.001～0.1 mg/L及0.1～5.0 mg/L质量浓度范围内均与溶出峰电流成良好的线性关系,检出限为0.0005 mg/L.该法可用于实际工业废水中汞的测定.     

Ultrathin conjugated polymer network films of carbazole functionalized poly(p-phenylenes) via electropolymerization

Ultrathin films of a cross-linked and chemically distinct conjugated poly(p-phenylene) network via electropolymerization are described. The amphiphilic network precursor was synthesized by incorporating the alkoxy carbazole group (-O(CH2)5Cb) to a poly(p-phenylene) (C6PPPOH) backbone. In order to investigate the combined thin film electrochemical and photophysical properties of poly(p-phenylene)s and polycarbazole conjugated polymers, C6PPPC5Cb was deposited on substrates using the Langmuir Blodgett Kuhn (LBK) method. The monolayer isotherm of the polymer, C6PPPC5Cb, showed a liquid expanded region slightly different from the parent polymer C6PPPOH. Multilayers (up to 30 layers) were transferred to different substrates such as quartz, gold coated LaSFN9 and ITO substrates for analysis. For conversion to a conjugated polymer network (CPN) film, the electroactive carbazole group was electropolymerized using cyclic voltammetry (CV) resulting in polycarbazole linking units. The differences in the film properties and corresponding changes in the electrochemical behavior indicate the importance of film thickness and electron/ion transport process in cross linked network films. From the electrochemical studies, the scan rate was found to have a considerable effect on electropolymerization with higher oxidation and reduction peak values found for the rigid network polymer compared to the uncrosslinked polymers.     

Ni(OH)2修饰的三聚氰胺泡沫用于可压缩超级电容器电极

通过化学镀和电化学镀的方法制备了一种Ni(OH)₂电化学活性材料修饰三聚氰胺泡沫(MF)可压缩骨架的超级电容器电极材料MF/Ni(OH)₂。MF/Ni(OH)₂可压缩电极材料表现出最佳的电容性能,例如循环稳定性(即使在40 mA/cm^-3的电流密度下经过2000次充放电循环后,可压缩电极仍能保持90.63%的初始电容)和可压缩稳定性(即使在压缩率为50%时,仍具有97.88%的电容保持率)。层状可压缩超级电容器由MF/Ni(OH)₂弹性材料作为阳极,镍/碳(Ni/C)为阴极以及实验室中常用的滤纸作隔膜材料组成。这种超级电容器装置在不同的压缩下表现出良好的电化学性能和优异的压缩稳定性。最后,使用可压缩的超级电容器来点亮LED灯,以展示其在柔性电子设备中的应用。这些优化的电化学和机械性能表明MF/Ni(OH)₂可作为可压缩超级电容器的应用中的候选电极。     

Poly(vinylferrocenium) coated disposable pencil graphite electrode for DNA hybridization

Poly(vinylferrocenium) (PVF⁺) modified electrode was developed in this study for the electrochemical sensing of DNA based on the oxidation signals of polymer, adenine and guanine. Experimental parameters, such as; polymeric film thickness, DNA immobilization time and DNA concentration were examined in order to obtain more sensitive and selective electrochemical signals. After optimization studies, DNA hybridization was investigated.