全钒氧化还原液流电池用石墨毡电极的分步氧化活化

石墨毡电极是组成钒电池的关键材料,其较低的电化学活性是造成钒电池功率密度较低的关键因素之一. 本论文采用一种简便的石墨毡电极分步氧化活化法,先将石墨毡在高锰酸钾溶液中进行氧化,后置于活化溶液中激发其反应活性. 通过对处理后的石墨毡进行循环伏安、交流阻抗测试、XPS以及SEM表征,发现氧化时间和活化溶液组成是影响电极性能的因素,在本文中,先经过3天氧化时间,后在配比为3:1的活化溶液中处理的电极,较其他方法处理的电极,电荷传递电阻明显降低,其与溶液之间的接触电阻最低,为7.33 Ω·cm ²,氧化还原峰值比更接近于1,有效提高了反应的活性与可逆性,经X射线光电子能谱分析发现性能提高的原因与表面含氧官能团数目增加有关. 单电池性能测试结果进一步证实,利用该方法处理的石墨毡为电极的单电池,较未经处理的电池相比性能更优,有更高的放电容量和能量效率,在100 mA·cm ^-2电流密度下,能量效率较未处理电极高出7.47%. 与热处理法、酸处理法及电化学氧化法相比较,该方法不需要辅助设备,不消耗能源.     

Detrimental role of hydrogen evolution and its temperature-dependent impact on the performance of vanadium redox flow batteries

This paper addresses the damaging role of the parasitic hydrogen evolution reaction(HER) in the negative half-cell of a vanadium redox flow battery(VRFB) on state-of-the-art carbon felt electrodes at different temperatures. It was found that increasing the temperature resulted in a better catalytic performance for both the positive and negative half-cell reactions. In addition, increasing the temperature significantly enhanced the undesired HER at the negative side. Operating the VRFB cell at higher temperature led to a decrease in the coulombic efficiency attributed to the higher hydrogen production. More pronounced hydrogen production caused an oxidation on the surface of the carbon fibers and a degradation of the electrode as indicated from scanning electron microscopy and X-ray photoelectron spectroscopy measurements. This observed degradation results in fading of the overall performance of the vanadium redox flow battery over time.     

全钒液流电池铂氢微型参比电极体系的构筑与性能

铂丝电极表面上电沉积一层金属钯,用阴离子交换隔膜材料封装,制得铂氢微型参比电极,工艺简单、稳定性高. 将该微型参比电极应用于全钒储能电池性能研究,可内置于电池多孔电极内部,监测电池正负极充放电性能. 结果显示,电池容量衰减主要归因于电解液中的活性物质V(IV)的逐渐减少及V(V)的积累导致正负极活性物质不平衡.     

石墨烯基电极材料的设计和构建及其在电容去离子中的应用

电容去离子(CDI)是一种通过静电力作用将离子从水中去除的技术,电极是整个装置中为最为核心的部件,石墨烯因具有优异的导电性和巨大的比表面积等优势成为当前CDI电极材料的研究热点之一。目前对于CDI石墨烯电极的研究主要集中于石墨烯电极的合成,然而有关CDI性能与石墨烯电极制作工艺及电极材料自身结构之间的关系,缺少相关综述。本文系统介绍了CDI的基本原理与性能指标,综述了石墨烯电极材料的研究进展与电极制作工艺,重点分析、归纳和总结了石墨烯材料的特性(孔隙结构、导电性、亲疏水性)对CDI性能的影响,最后对CDI中石墨烯电极材料今后的发展进行了总结和展望。     

Electrochemical sensing of bisphenol A on single-walled carbon nanotube paper electrodes

The electrochemical detection of BPA often requires modification of electrodes to overcome BPA′s slower kinetics and higher oxidation potential. This work reports a modification-free, paper electrode based on vacuum-filtered SWCNT thin film. The prepared electrode does not need to be polished or transferred into the conducting substrates. The linear sweep voltammetric detection showed a linear response from 0.5–10 μM and 25–100 μM with the experimental LOD of 1.0 μM (S/N=3). The interference study and good recovery percentage (93–105 %) in real water samples demonstrated the method‘s selectivity. The sensor can be promising for developing a simple, low-cost, portable, and paper-based BPA monitoring system.     

Electroanalysis at Diamond‐Like and Doped‐Diamond Electrodes

Diamond as a high performance material occupies a special place due to its in many ways extreme properties, e.g., hardness, chemical inertness, thermal conductivity, optical properties, and electric characteristics. Work mainly over the last decade has shown that diamond also occupies a special place as an electrode material with interesting applications in electroanalysis. When made sufficiently electrically conducting for example by boron‐doping, ‘thin film' and ‘free–standing' diamond electrodes exhibit remarkable chemical resistance to etching, a wide potential window, low background current responses, mechanical stability towards ultrasound induced interfacial cavitation, a low ‘stickiness' in adsorption processes, and a high degree of ‘tunability' of the surface properties. This review summarizes some of the recent work aimed at applying conductive (boron‐doped) diamond electrodes to improve procedures in electroanalysis.     

Metal Negatrode Supercapatteries: Advancements,Challenges, and Future Perspectives for High-Performance Energy Storage

Metal negatrode supercapattery (MNSC) is an emerging technology that combines the high energy storage capabilities of batteries with the high-power delivery of supercapacitors, thereby offering promising solutions for various applications, such as energy storage systems, electric vehicles, and portable electronics. This review article presents a comprehensive analysis of the potential of MNSCs as a prospective energy storage technology. MNSCs utilize a specific configuration in which the negatrode consists of a metal or metal-rich electrode, such as sodium, aluminum, potassium, or zinc, whereas the positrode functions as a supercapacitor electrode. The utilization of negatrodes with low electrochemical potential and high electrical conductivity is crucial for achieving high specific energy in energy storage devices, despite facing numerous challenges. The present study discusses the design and fabrication aspects of MNSCs, including the selection of appropriate metal negatrodes, electrolytes, and positrodes, alongside the fundamental operational mechanisms. Additionally, this review explores the challenges encountered in MNSCs and proposes solutions to enhance their performance, such as addressing dendrite formation and instability of metal electrodes.     

室温钠离子储能电池电极材料结构研究进展

随着风能和太阳能等新能源的大规模发展及未来智能电网的实现,大规模储能系统显得越来越重要.室温钠离子电池以较低的成本再次引起了研究者的兴趣,并成为一种有前途、低成本的储能体系.目前,已提出多种材料可作为钠离子电池的电极材料.一般而言,材料的性质主要由材料的晶体结构决定,本文主要介绍目前提出的多种可行室温钠离子电池电极材料的晶体结构,希望通过总结已有电极材料的晶体结构,对新材料的设计提供指导.     

An iridium oxide reference electrode for use in microfabricated biosensors and biochips

In this paper we argue for the use of iridium oxide (IrO(x)) electrodes as quasi-reference electrodes in microfabricated biosensors and biochips that operate in buffered solutions. The simple microfabrication of these electrodes consists of a one-step electrodeposition of IrO(x) onto a microfabricated platinum (Pt) electrode. The IrO(x) electrode potential was found to vary less than 20 mV over 9 days after stabilization for 1 day in a phosphate-buffered saline (PBS) solution; this behavior of the electrode potential was found to be easily reproduced. Moreover, the electrode potential was found to vary by less than 15 mV in the initial hour of its use; this behavior of the electrode potential was also found to be reproducible. The performance of a microfabricated glucose sensor employing an IrO(x) reference electrode is characterized in this paper in order to evaluate the usefulness of this new IrO(x) electrode as a quasi-reference electrode. The glucose sensor consists of a recessed microfabricated Pt electrode array, an electrodeposited IrO(x) film, an inner layer composed of an electropolymerized poly(m-phenylenediamine)/glucose oxidase (PMPD/GOx) film, and an outer or protective layer composed of Teflon and polyurethane (PU) films. The response of this sensor was found to be equivalent to the response of the same sensor employing a commercial Ag/AgCl reference electrode. These results show that a microfabricated IrO(x) electrode can be used as a quasi-reference electrode in microfabricated biosensors and biochips operating in buffered solutions.     

Iridium Oxide Film Electrodes for Anodic Stripping Voltammetry

The new iridium oxide film electrode, applied for the determination of lead(II), cadmium(II) and copper(II) traces using differential pulse anodic stripping voltammetry (DP ASV) is presented. The electrode display an interesting stripping voltammetric performance which compares with electrodes commonly used in voltammetry. The deposited film is known as anodically electrodeposited iridium oxide film (AEIROF). The AEIROF electrode is characterized by long‐term stability (more than 40 days) and very good reproducibility of the analytical signals in this time (≤12% for 0.5 μM of lead). The regeneration of iridium film is very simple in a time shorter than 60 seconds. The effects of various factors such as: thickness of AEIROF film, preconcentration potential and time, supporting electrolyte composition, potential interferences are optimized. The detection limit for AEIROF film electrode based on glassy carbon for an accumulation time of 30 s is as low as 7 nM for lead(II). The repeatability of the method at a concentration level of the lead(II) as low as 0.5 μM, expressed as RSD is 2.5% (n=10). The proposed method was successfully applied and validated by studying certified reference material CTA‐OTL‐1. Such an attractive use of ‘mercury–free’ ‐ environmentally friendly electrodes offers great promise to measure trace metals.     

海水淡化用碳基电极材料及电容去离子技术研究进展

电容去离子技术(Capacitive Deionization,CDI)可以通过断电或电极反接方式使盐离子脱附,达到电极再生的目的,实现电极的可循环利用,其在海水淡化处理技术中具有独特的优势,逐渐成为一种缓和淡水资源紧缺和水污染的极具前景的技术手段。近年来,CDI处理技术正在向电极高效、无二次污染方向转变,未来将进一步聚焦碳基电极材料功能化(碳材料,钛碳化物MXenes,掺杂改性石墨烯材料)、装置和工艺设计优化等重要方向。为深入研究CDI海水淡化技术机理,进一步探索CDI方法在实际应用中的潜力,分别对CDI的脱盐机理、电极材料、装置和工艺设计对电吸附效率和性能的研究进展进行了总结,回顾CDI脱盐效果与电极材料、CDI电池装置设计等因素之间的密切关系,并对CDI技术在海水淡化中的研究发展提出展望。     

NF/rGO/Co_3O_4/NiO电极的制备及在超级电容器中的应用

以泡沫镍(NF)为集流体,在优化好的电位、时间和浓度下,将还原氧化石墨烯(rGO)、金属氧化物(Co_3O_4和NiO)直接生长在泡沫镍上,制备了NF/rGO/Co_3O_4和NF/rGO/Co_3O_4/NiO电极.运用三电极体系对电极材料进行了恒流充放电(GCD)和交流阻抗(EIS)等测试.结果表明,复合材料NF/rGO/Co_3O_4/NiO具有较高的比容量(电流密度为2 A/g时,比容量达到1188.6 F/g)和较好的循环稳定性(2000周充放电后,稳定性达到80.5%).该材料还具有较高的倍率性能,当电流密度由2 A/g增至12 A/g时,倍率性能仍能达到75.7%.     

Evaluation of the zirconia pH sensor at 95° C

An yttria-stabilized zirconia electrode for measuring pH at elevated temperature and pressure has been described by Niedrach, who verified its response at 95°C in comparison with glass pH electrodes. The present paper reports studies at 95° C on zirconia tubes available from three different commercial sources. This study, conducted with conventional aqueous internal filling solution and conventional internal and external reference electrodes, was designed to obtain fundamental pH electrode parameters of slope, resistance, asymmetry potential, and time of response in standard buffers and known strength acids and bases. A coulometric experiment is reported to aid in assessing the efficiency of the zirconia electrode. Uncertain performance found in this evaluation may be attributed to chemical, physical, and surface problems in the commercially available zirconia tubes or to less than ideal pH response for zirconia membranes.     

Critical comparison of metallized and mediator-based carbon paste glucose biosensors

The performance of metallized carbon oxidase-based biosensors is critically compared with that of mediator-based enzyme electrodes. Dimethyl ferrocene and rhodium metal centers are used as model mediator and catalyst, respectively, in connection to carbon-paste electrode transducers and assays of glucose. The rhodium-containing bioelectrode displays enhanced selectivity (particularly improved discrimination against ascorbic acid), lower sensitivity, faster response time, greater oxygen dependence, and similar detection limit in comparison to the mediated electrode. In addition to assessing the relative merits of both strategies, the data offer useful insights into the behavior of these ‘first’- and ‘second-generation’ oxidase amperometric electrodes.     

High electro-catalytic graphite felt/Mn O2composite electrodes for vanadium redox flow batteries

A mild and simple synthesis process for large-scale vanadium redox flow batteries(VRFBs)energy storage systems is desirable.A graphite felt/Mn O_2(GF-MNO)composite electrode with excellent electrocatalytic activity towards VO~(2+)/VO_2~+redox couples in a VRFB was synthesized by a one-step hydrothermal process.The resulting GF-MNO electrodes possess improved electrochemical kinetic reversibility of the vanadium redox reactions compared to pristine GF electrodes,and the corresponding energy efficiency and discharge capacity at 150 m A cm~(-2)are increased by 12.5%and 40%,respectively.The discharge capacity is maintained at 4.8 A h L~(-1)at the ultrahigh current density of 250 m A cm~(-2).Above all,80%of the energy efficiency of the GF-MNO composite electrodes is retained after 120 charge-discharge cycles at 150 m A cm~(-2).Furthermore,these electrodes demonstrated that more evenly distributed catalytic active sites were obtained from the Mn O_2particles under acidic conditions.The proposed synthetic route is facile,and the raw materials are low cost and environmentally friendly.Therefore,these novel GF-MNO electrodes hold great promise in large-scale vanadium redox flow battery energy storage systems.     

Comparison of different carbon nanostructures influence on potentiometric performance of carbon paste electrode

Recently, different carbon nanomaterials were introduced for construction of electrochemical sensors. In this study, the influence of carbon nanomaterial on performance of carbon paste potentiometric electrode was investigated. In this manner, different kinds of carbon nanomaterial, i.e., graphene, graphene oxide and carbon nanotube (CNT) were used as a conduction phase in carbon paste electrode. Then, potentiometric characteristics of the corresponding paste electrodes such as calibration slope, linear range, detection limit, response time and stability were compared with each other. The results appeared comprehensive findings about the role of electrode’s content in electrochemical performance.     

新型芯片电泳柱端安培检测系统的构建与评价

自行设计开发了一套便于与电泳芯片集成的一体式柱端安培检测池系统．该系统由整块透明有机玻璃精密加工而成,包括电泳芯片支架和安培检测池两部分,芯片可通过芯片插槽和不锈钢夹具固定在芯片支架上,各种检测用电极可直接通过螺母固定在安培检测池中．以100μmol／L的DA为模式分析物,分别采用直径为100、300和500μm的铂金圆盘电极与表观直径为240μm的碳纤维电极作为工作电极均在该装置上实现了良好组装和高灵敏检测．采用碳纤维工作电极对该系统的检测参数进行了优化．测试结果表明该系统在电化学清洗程序下连续六次测定100μmol／L多巴胺的峰电流相对标准偏差为3．2％,保留时间相对标准偏差为0．5％,DA的检测限为0．4μmol／L（按照S／N=3计）．该系统体积小巧,测试稳定,检测灵敏度较高,工作电极更换方便,适合作为芯片电泳柱端安培检测通用平台．     

基于不同工作电极的亚硝酸盐电化学传感器

亚硝酸盐是环境和生物循环中不可或缺的一部分,但其浓度超标不仅会污染环境,还会致癌。因此对亚硝酸盐实现高效、快速精密检测具有重要的科学和实际意义。基于电化学传感技术的污染物分析与检测已成为研究热点,尤其工作电极的选用和设计对提升响应速度、灵敏度、检测限及降低成本、简化操作等至关重要而备受研究者广泛关注。本文将以玻碳电极、碳糊电极、金属薄膜、聚合物薄膜及碳布电极为分类,针对亚硝酸盐的检测,详细综述基于不同电极的电化学传感器的研究进展。以期通过构建方法和电催化性能的对比为构建新型传感器提供理论与实际指导。     

Telluride-Based Materials: A Promising Route for High Performance Supercapacitors

As supercapacitor (SC) technology continues to evolve, there is a growing need for electrode materials with high energy/power densities and cycling stability. However, research and development of electrode materials with such characteristics is essential for commercialization the SC. To meet this demand, the development of superior electrode materials has become an increasingly critical step. The electrochemical performance of SCs is greatly influenced by various factors such as the reaction mechanism, crystal structure, and kinetics of electron/ion transfer in the electrodes, which have been challenging to address using previously investigated electrode materials like carbon and metal oxides/sulfides. Recently, tellurium and telluride-based materials have garnered increasing interest in energy storage technology owing to their high electronic conductivity, favorable crystal structure, and excellent volumetric capacity. This review provides a comprehensive understanding of the fundamental properties and energy storage performance of tellurium- and Te-based materials by introducing their physicochemical properties. First, we elaborate on the significance of tellurides. Next, the charge storage mechanism of functional telluride materials and important synthesis strategies are summarized. Then, research advancements in metal and carbon-based telluride materials, as well as the effectiveness of tellurides for SCs, were analyzed by emphasizing their essential properties and extensive advantages. Finally, the remaining challenges and prospects for improving the telluride-based supercapacitive performance are outlined.