Electrochimica Acta最新文献_第7页

Cu-Zn layered double hydroxides as high-performance electrode for supercapacitor applications 作为高性能电极的铜锌层状双氢氧化物在超级电容器中的应用

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-22 DOI: 10.1016/j.electacta.2024.145106

Supercapacitors have evoked considerable attention nowadays under the realm of energy storage devices due to some of their intriguing properties such as long cycling stability, high power density, and low cost. Layered double hydroxides, known for their unusual structural and electrochemical properties, have gained prominence among electrode materials due to their high specific capacitance and exceptional cycle stability. This study investigates the viability of Cu-Zn layered double hydroxides (LDH) as electrode material for supercapacitor applications. Copper (Cu) and Zinc (Zn) present in the LDH framework create synergistic effects that increase the material's electrochemical properties. The current study investigates the morphology and electrochemical behaviour of Cu-Zn LDH, emphasizing their suitability as supercapacitor electrodes. Furthermore, various characterization techniques such as XRD, FTIR, SEM, TEM, and XPS were employed to uncover the material's inherent properties. A specific capacitance of 265 F/g was obtained at a current density of 1 mA/cm² in the three-electrode configuration. Further, an asymmetric device furnished a specific capacitance of 51 F/g with an energy density of 7.14 Wh/kg and a power density of 121.94 W/kg. Additionally, the material maintains 75 % of its original capacitance after 1000 cycles, demonstrating its exceptional stability. The obtained electrochemical parameters for the as-synthesized material demonstrate its feasibility as an energy storage device.

超级电容器具有长循环稳定性、高功率密度和低成本等引人入胜的特性，如今已在储能设备领域引起广泛关注。层状双氢氧化物以其不寻常的结构和电化学特性而闻名，由于其高比电容和优异的循环稳定性，在电极材料中占据了重要地位。本研究探讨了铜锌层状双氢氧化物（LDH）作为超级电容器电极材料的可行性。LDH 框架中的铜（Cu）和锌（Zn）会产生协同效应，从而提高材料的电化学性能。目前的研究调查了铜锌 LDH 的形态和电化学行为，强调了它们作为超级电容器电极的适用性。此外，还采用了 XRD、FTIR、SEM、TEM 和 XPS 等各种表征技术来揭示材料的内在特性。在三电极配置中，电流密度为 1 mA/cm2 时的比电容为 265 F/g。此外，不对称装置的比电容为 51 F/g，能量密度为 7.14 Wh/kg，功率密度为 121.94 W/kg。此外，该材料在 1000 次循环后仍能保持 75% 的原始电容，显示了其卓越的稳定性。合成材料获得的电化学参数证明了其作为储能装置的可行性。

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引用次数: 0

Cork activated carbon as a new sustainable electrode for electrochemical desalination: Customized surface chemistry for improved performance 软木活性炭作为电化学海水淡化的新型可持续电极：定制表面化学，提高性能

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-22 DOI: 10.1016/j.electacta.2024.145120

Capacitive deionization (CDI) desalination has proven to be a promising solution to combat water scarcity, standing out for its efficiency and low energy consumption. In this study we investigated the feasibility and sustainability of using recycled cork stoppers as carbon electrodes for CDI. The cork stoppers underwent carbonization at three different temperatures (500, 700 °C, and 900 °C) and then activation with Potassium hydroxide (KOH) at 850 °C. The as-obtained electrodes (ECAC) demonstrated salt adsorption capacities (SAC) comparable to other biowaste carbon electrodes. The potential of zero charge (E_PZC) values of the electrodes reflected the influence of synthesis conditions on their surface properties. Considering the E_PZC, symmetric configuration, in which both electrodes (cathode (-) || (+) anode) were made of the same material (ECAC(-)||(+)ECAC), and asymmetric electrodes, using different materials (ECAC(-)||(+)YP80-F) were investigated. The use of asymmetric electrodes proved to be mandatory to obtain high charging efficiency and desalination capacity. It was found that the E_PZC determines the correct electrode configuration to prevent the deleterious effect of co-ions repulsion. Herein, we used the carbonization temperature as a new strategy to tune the E_PZC in order to obtain electrodes with the desired surface properties for application in CDI, thus avoiding the usual laborious and costly chemical-based approaches. Regarding the desalination performance, asymmetry combined with the appropriate cell potential was optimized to obtain charging efficiencies close to 100 % and maximum SAC, thus resulting in minimized specific energy consumption. This study not only confirms the efficacy of cork stoppers as electrodes for CDI but also promotes the use of recycled materials, contributing to a circular economy and environmental impact mitigation.

电容式去离子（CDI）海水淡化因其高效和低能耗而被证明是解决水资源短缺问题的一种有前途的解决方案。在这项研究中，我们调查了使用回收软木塞作为 CDI 碳电极的可行性和可持续性。软木塞在三种不同温度（500、700 和 900 ℃）下碳化，然后在 850 ℃ 下用氢氧化钾（KOH）活化。获得的电极（ECAC）的盐吸附能力（SAC）与其他生物废料碳电极相当。电极的零电荷电位（EPZC）值反映了合成条件对其表面特性的影响。考虑到 EPZC，研究了对称配置（即两个电极（阴极 (-) || (+) 阳极）均由相同材料制成（ECAC(-)||(+)ECAC））和非对称电极（使用不同材料（ECAC(-)||(+)YP80-F））。事实证明，要获得较高的充电效率和脱盐能力，必须使用不对称电极。研究发现，EPZC 决定了正确的电极配置，以防止共离子排斥的有害影响。在此，我们使用碳化温度作为调整 EPZC 的新策略，以获得具有所需表面特性的电极，应用于 CDI，从而避免了通常费力且昂贵的化学方法。在海水淡化性能方面，不对称与适当的电池电位相结合进行了优化，以获得接近 100% 的充电效率和最大 SAC，从而最大限度地降低了比能耗。这项研究不仅证实了软木塞作为 CDI 电极的功效，还促进了再生材料的使用，为循环经济和减轻环境影响做出了贡献。

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引用次数: 0

Bioelectrochemical performance on constructed wetland-microbial fuel cells operated under diffuse and direct solar radiation using root exudates as endogenous substrate to feed an electroactive biofilm 利用根系渗出物作为内源基质为电活性生物膜提供养分，在漫射和直射太阳辐射下运行的构建湿地-微生物燃料电池的生物电化学性能

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-22 DOI: 10.1016/j.electacta.2024.145116

Exploiting fossil fuels through conventional technologies focused on energy production has led to severe environmental adversities, mainly affecting global warming and climate change. Constructed wetland-microbial fuel cells (CW-MFC) have emerged as an innovative technology that could mitigate these effects. One of the main limitations of the CW-MFC system is the low power density generated. This study evaluated the impact of diffuse (CW-MFC1) and direct (CW-MFC2) solar radiation intensity to enhance bioelectrochemical performance. To do this, the CW-MFC was inoculated with the Geobacter sulfurreducens bacteria as a bioelectrocatalyst, which was fed with the root exudates of the macrophyte Juncus effusus. The change from diffuse to direct solar radiation increased the electroactivity of the system by 43% in terms of power density, cathodic potential, anodic potential, and internal resistance, resulting in a maximum performance of 128.7 mW/m², 172 mV, −290 mV, and 204 Ω respectively. This was obtained from a concentration of 35.3 mg/L of root exudates (total organic carbon). The analysis of results determined that solar radiation is a predominant factor that directly affects the photosynthetic efficiency and coulombic efficiency of CW-MFC by controlling the rhizodeposition process of the macrophytes, where the amount of bioelectricity produced depends on the amount of exudates discharged by the root system towards the rhizosphere.

通过以能源生产为重点的传统技术开采化石燃料导致了严重的环境问题，主要影响到全球变暖和气候变化。建造湿地微生物燃料电池（CW-MFC）作为一种创新技术已经出现，可以减轻这些影响。CW-MFC 系统的主要局限之一是产生的功率密度较低。本研究评估了漫射（CW-MFC1）和直接（CW-MFC2）太阳辐射强度对提高生物电化学性能的影响。为此，在 CW-MFC 中接种了作为生物电催化剂的 Geobacter sulfurreducens 细菌，并以大型藻类 Juncus effusus 的根部渗出物为原料。将太阳辐射从漫射改为直射后，该系统在功率密度、阴极电位、阳极电位和内阻方面的电活性提高了 43%，最大性能分别为 128.7 mW/m2、172 mV、-290 mV 和 204 Ω。这是在根渗出物（总有机碳）浓度为 35.3 毫克/升的情况下获得的。结果分析表明，太阳辐射是直接影响 CW-MFC 光合效率和库仑效率的主要因素，它通过控制大型植物的根瘤沉积过程来影响 CW-MFC 的光合效率和库仑效率。

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引用次数: 0

Oxygen reduction reaction on Ag nanocatalysts prepared by the microemulsion method 微乳液法制备的银纳米催化剂上的氧还原反应

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-21 DOI: 10.1016/j.electacta.2024.145098

The microemulsion (water-in-oil) method is used to prepare novel silver catalysts onto three different carbon supports (multi-walled carbon nanotubes (MWCNT), mesoporous carbon (MC) and Vulcan carbon (C)). It allows to control the Ag particle growth and produces particles that range between 2 and 3 nm. The Ag-based catalysts are characterised by scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS). The electrocatalytic activity towards the oxygen reduction reaction (ORR) in 0.1 M KOH is studied using the rotating disc electrode method. High-angle annular dark-field (HAADF) STEM images reveal the Ag particle size range between 1.8 and 2.4 nm, and the EDS mapping shows uniform Ag distribution on the substrates used. Ag1/MC (two-step synthesis) and Ag2/MC (one-step synthesis) catalysts prepared onto the MC support show the highest mass activity of 30–37 A g⁻¹. The two-step synthesis method is preferred to prepare Ag/MWCNT and Ag/C catalysts. The mass activity of the Ag1/MWCNT catalyst is more than two times higher than that of Ag2/MWCNT. Ag1/MWCNT shows the highest electrochemical stability after the accelerated durability test, with only a 6 mV shift in half-wave potential. The microemulsion method is very promising for the production of highly stable Ag-based catalysts with Ag particles smaller than 3 nm in size.

微乳液（油包水）法用于在三种不同的碳载体（多壁碳纳米管 (MWCNT)、介孔碳 (MC) 和火神碳 (C)）上制备新型银催化剂。它可以控制银颗粒的生长，并产生 2 至 3 纳米的颗粒。通过扫描透射电子显微镜（STEM）和能量色散 X 射线光谱（EDS）对银基催化剂进行了表征。使用旋转圆盘电极法对 0.1 M KOH 中氧还原反应 (ORR) 的电催化活性进行了研究。高角度环形暗场（HAADF）STEM 图像显示，Ag 颗粒的尺寸范围在 1.8 至 2.4 nm 之间，EDS 图谱显示 Ag 在所用基底上分布均匀。在 MC 载体上制备的 Ag1/MC（两步合成法）和 Ag2/MC（一步合成法）催化剂显示出 30-37 A g-1 的最高质量活性。两步合成法是制备 Ag/MWCNT 和 Ag/C 催化剂的首选方法。Ag1/MWCNT 催化剂的质量活性是 Ag2/MWCNT 催化剂的两倍多。在加速耐久性测试后，Ag1/MWCNT 显示出最高的电化学稳定性，半波电位仅有 6 mV 的偏移。微乳液法对于生产 Ag 颗粒尺寸小于 3 nm 的高稳定性 Ag 基催化剂非常有前景。

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引用次数: 0

Redox kinetics of multi-electron transfer reactions of polyoxometalates (POMs) relevant to electrochemical devices 与电化学装置有关的聚氧化金属（POMs）多电子转移反应的氧化还原动力学

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-21 DOI: 10.1016/j.electacta.2024.145107

The formal equilibrium potential (E^0′) and heterogeneous rate constant (k⁰) are characteristics of any electron-transfer reaction. The estimation of these characteristics for very fast multiple electron-transfer reactions of polyoxometalates (POMs) relevant to various applications including redox flow batteries, hydrogen storage materials, and electrocatalysis is highly challenging by the conventional electrochemical methods. Therefore, E^0′and k⁰ (k⁰∼10^–2 cm sec^‑1) of such reactions (for e.g., that of tungstosilicic acid (SiW₁₂) and phosphotungstic acid (PW₁₂)) separated by small potential windows are estimated from the background current free higher harmonic response of large-amplitude AC voltammetry. For SiW₁₂/PW₁₂ redox species, the E^0′ values of processes 1, 2, and 3 estimated from the minima of second harmonic response are -0.326/-0.127, -0.530/-0.380 and -0.691/-0.701 (V vs. Ag/AgCl), respectively. The k⁰ values of the first redox process (P1) of SiW₁₂ (SiW₁₂/ SiW₁₂^-,4.8 × 10^–2 cm sec^‑1) and PW₁₂ (PW₁₂/PW₁₂^-,5.2 × 10^–2 cm sec^‑1) estimated from the large-amplitude AC voltammetry are further validated through the impedance measurement (2.1 × 10^–2 and 2.4 × 10^–2 cm sec^‑1). The uniqueness of large-amplitude AC voltammetry over conventional DC techniques and impedance spectroscopy is illustrated. The relevance of k⁰ values in the context of electrocatalytic processes and RFBs system is also presented.

形式平衡电势（E0′）和异质速率常数（k0）是任何电子转移反应的特征。对于与氧化还原液流电池、储氢材料和电催化等各种应用相关的聚氧化金属酸盐（POMs）的快速多重电子转移反应，用传统的电化学方法估算这些特征具有很大的挑战性。因此，此类反应（例如钨硅酸（SiW12）和磷钨酸（PW12）的反应）的 E0′和 k0（k0∼10-2 cm sec-1）被小电位窗口隔开，我们通过大振幅交流伏安法的背景电流自由高次谐波响应来估算。对于 SiW12/PW12 氧化还原物种，根据二次谐波响应的最小值估算出过程 1、2 和 3 的 E0′ 值分别为 -0.326/-0.127、-0.530/-0.380 和 -0.691/-0.701（V vs. Ag/AgCl）。大振幅交流伏安法估算出的 SiW12（SiW12/ SiW12-，4.8 × 10-2 厘米秒-1）和 PW12（PW12/PW12-，5.2 × 10-2 厘米秒-1）第一个氧化还原过程（P1）的 k0 值通过阻抗测量（2.1 × 10-2 和 2.4 × 10-2 厘米秒-1）得到了进一步验证。这说明了大振幅交流伏安法相对于传统直流技术和阻抗光谱法的独特性。此外，还介绍了 k0 值与电催化过程和 RFB 系统的相关性。

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引用次数: 0

Organic-inorganic coupled Ti3CN MXene achieving the excellent sodium-ion storage performance 实现优异钠离子存储性能的有机-无机耦合 Ti3CN MXene

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-21 DOI: 10.1016/j.electacta.2024.145102

Two-dimensional (2D) transition metal carbides/nitrides (MXenes) are attracting considerable attention due to their unique multilayered structure. However, the practical application of MXenes as electrode materials is hampered by sluggish ions diffusion kinetics and serious volume variation during charging and discharging cycles. Herein, the organic-inorganic coupled Ti₃CN (Ti₃CNNHSA) composites were constructed by anchoring succinic acid (SA) molecules into the interlayer of Ti₃CN. The anchored SA molecules contribute pillar effects to increase interlayer spacing and inhibit the volume contraction during Na⁺ ions extraction processes, as well as strain effects to mitigate volume expansion during Na⁺ ions insertion processes. Consequently, the Ti₃CNNHSA composites not only exhibit the increased interlayer spacing and rapid ions transfer paths but also deliver the enhanced structural stability and maximum utilization of layered structure, realizing extraordinary cycle stability and high rate capability. The Ti₃CNNHSA exhibits a superior capacity retention of 95.2% after 400 cycles at 0.1 A g^-1. The Ti₃CNNHSA//AC sodium-ion capacitor (SIC) also displays a capacity retention of 84.1% after 1200 cycles at 1.0 A g^-1 and a high energy density of 76 Wh kg^-1 at the power density of 200 W kg^-1. Such an organic-inorganic coupled Ti₃CNNHSA sheds light on the development of 2D layered materials.

二维（2D）过渡金属碳化物/氮化物（MXenes）因其独特的多层结构而备受关注。然而，MXenes 作为电极材料的实际应用却受到离子扩散动力学迟缓和充放电循环过程中体积变化严重的阻碍。本文通过在 Ti3CN 层间锚定琥珀酸（SA）分子，构建了有机-无机耦合 Ti3CN（Ti3CNNHSA）复合材料。锚定的 SA 分子具有支柱效应，可增加层间间距并抑制 Na+ 离子萃取过程中的体积收缩，还具有应变效应，可减轻 Na+ 离子插入过程中的体积膨胀。因此，Ti3CNNHSA 复合材料不仅增加了层间距和离子快速传输路径，还增强了结构稳定性并最大限度地利用了层状结构，实现了超常的循环稳定性和高速率能力。Ti3CNNHSA 在 0.1 A g-1 条件下循环 400 次后，容量保持率达到 95.2%。Ti3CNNHSA//AC 钠离子电容器（SIC）在 1.0 A g-1 的条件下循环 1200 次后，容量保持率也达到了 84.1%，在功率密度为 200 W kg-1 时，能量密度高达 76 Wh kg-1。这种有机-无机耦合 Ti3CNNHSA 为二维层状材料的发展提供了启示。

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引用次数: 0

Using the nonlinearity of a PEM water electrolyzer cell for its dynamic model characterization 利用 PEM 水电解槽的非线性特性进行动态模型表征

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-21 DOI: 10.1016/j.electacta.2024.145085

The voltage response of a water electrolyzer at low frequencies is characterized by a combination of a static polarization curve and dynamic, capacitive effects. In this paper, a model combining these two phenomena is created, which incorporates the Butler–Volmer equation in parallel with a capacitance in order to produce differential equations for the activation overpotentials separately on both electrodes. A parameter fitting methodology is then developed for obtaining the seven model parameters from a set of low-frequency, high-amplitude dynamic waveform measurements. The method is further implemented in an electrolyzer modeling toolbox for MATLAB. The model built in this study is proven to predict well both static and dynamic voltage responses down to the 1 Hz frequency. At higher frequencies and at small amplitudes the model reduces to the Randles equivalent circuit, and in a static case to the polarization curve of the cell. The proposed methodology can be used for probing individual electrode properties with full-cell measurements and providing a reliable tool for simulating water electrolyzer voltage responses with arbitrary waveforms and amplitudes.

水电解槽在低频下的电压响应具有静态极化曲线和动态电容效应相结合的特点。本文创建了一个结合这两种现象的模型，该模型将巴特勒-伏尔默方程与电容并联，以分别生成两个电极上活化过电位的微分方程。然后开发了一种参数拟合方法，用于从一组低频、高振幅动态波形测量中获取七个模型参数。该方法在 MATLAB 的电解槽建模工具箱中得到了进一步实施。事实证明，本研究建立的模型可以很好地预测频率低至 1 Hz 的静态和动态电压响应。在频率较高和振幅较小的情况下，该模型可还原为兰德尔等效电路，在静态情况下可还原为电池的极化曲线。所提出的方法可用于通过全电池测量探测单个电极的特性，并为模拟任意波形和振幅的水电解槽电压响应提供可靠的工具。

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引用次数: 0

Two-dimensional heterostructure of MXene-derived V2O5·H2O and graphene with enhanced Zn-ion storage capability 具有更强锌离子存储能力的二维异质结构--源于 MXene 的 V2O5-H2O 和石墨烯

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-21 DOI: 10.1016/j.electacta.2024.145093

Aqueous rechargeable zinc-ion batteries (ZIBs) are promising candidates for gird-scale energy storage with economic and environmental advantages. Layered hydrated vanadium oxides with multivalent and “lubricating” effect receive much attention in ZIBs. However, the application of them is suffering from the poor intrinsic conductivity and the unstable structure. Herein, a unique 2D/2D heterostructure of δ-V₂O₅·H₂O nanobelts (VO) and reduced graphene oxide (rGO) is designed as cathode for ZIBs (denoted as VOG). The stronger interface coupling and the shorter ion transport pathways impart the VOG electrode impressive stability and fast ions diffusion kinetics. Specifically, the VOG cathode delivers a superior capacity of 342 mAh g⁻¹ at 1 A g⁻¹ and a remarkable rate capability of 280 mAh g⁻¹ at a quite high rate of 10 A g⁻¹. The energy storage mechanism involved is investigated by systematical characterizations. The exploration of such 2D/2D heterostructure materials with strong synergy sheds light on the rational design of high performanced AZIBs.

水性可充电锌离子电池（ZIBs）是具有经济和环境优势的大规模能源储存的理想选择。具有多价和 "润滑 "效应的层状水合钒氧化物在锌离子电池中备受关注。然而，它们在应用过程中存在着本征导电性差、结构不稳定等问题。在此，我们设计了一种独特的 2D/2D 异质结构：δ-V2O5-H2O 纳米颗粒（VO）和还原氧化石墨烯（rGO），作为 ZIB 的阴极（简称 VOG）。更强的界面耦合和更短的离子传输路径赋予了 VOG 电极令人印象深刻的稳定性和快速离子扩散动力学。具体来说，VOG 阴极在 1 A g-1 的条件下可提供 342 mAh g-1 的超强容量，在 10 A g-1 的相当高的速率条件下可提供 280 mAh g-1 的显著速率能力。我们通过系统表征研究了其中的储能机制。对这种具有强大协同作用的二维/二维异质结构材料的探索，为高性能 AZIB 的合理设计提供了启示。

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引用次数: 0

Anion-intercalation pseudocapacitance in oxygen vacancy-rich spinel-perovskite NiFe2O4-LaFeO3 nanocomposite for high energy density asymmetric supercapacitor application 用于高能量密度不对称超级电容器的富氧空位尖晶石-perovskite NiFe2O4-LaFeO3 纳米复合材料中的阴离子互电位伪电容

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-21 DOI: 10.1016/j.electacta.2024.145104

Oxide nanomaterials have attracted significant attention as energy storage materials. The combination of spinel-perovskite oxides as nanocomposites creates dense oxygen vacancies

(V_{O})

at the hetero-interface.

V_{O}

present in the complex oxides are indispensable for energy conversion applications. Herein, we demonstrated the one pot synthesis of spinel-perovskite NiFe₂O₄-xLaFeO₃ nanocomposite and investigated the phase formation using variable temperature powder X-ray diffraction of the gel precursor. The role of oxygen-vacancy mediated tuneable redox transitions in NiFe₂O₄-xLaFeO₃ nanocomposite has been understood. The anion-intercalation-based pseudocapacitance and the oxygen intercalation have been exploited for high-performance electrochemical energy storage. The NiFe₂O₄–2LaFeO₃ exhibited a high specific capacity of 652 C g⁻¹ at a current density of 2 A g⁻¹. The fabricated NiFe₂O₄–2LaFeO₃||NiCo₂O₄ asymmetric supercapacitor device (ASC) exhibited excellent cyclability over 20,000 cycles with superior capacity retention and high Coulombic efficiency (92 %) and achieved a high energy density of 42.5 Wh kg⁻¹ at a power density of 1500 W kg⁻¹. The presence of

V_{O}

and the mixed-valence states of Fe^2+/3+ were confirmed by XPS-depth profiling. The tuneable redox transition of Fe^2+/3+ and

V_{O}

contribute to the higher pseudocapacitance response.

氧化物纳米材料作为储能材料备受关注。尖晶石-perovskite 氧化物的组合作为纳米复合材料，会在异质界面产生密集的氧空位（VO）。存在于复合氧化物中的氧空位是能量转换应用中不可或缺的。在此，我们展示了尖晶石-perovskite NiFe2O4-xLaFeO3 纳米复合材料的一锅合成，并利用凝胶前驱体的变温粉末 X 射线衍射研究了相的形成。我们了解了氧空位介导的可调氧化还原转变在 NiFe2O4-xLaFeO3 纳米复合材料中的作用。基于阴离子插层的假电容和氧插层已被用于高性能电化学储能。在电流密度为 2 A g-1 时，NiFe2O4-2LaFeO3 的比容量高达 652 C g-1。所制备的 NiFe2O4-2LaFeO3||NiCo2O4 不对称超级电容器器件（ASC）在 20,000 次循环中表现出卓越的循环能力、出色的容量保持能力和较高的库仑效率（92%），并在功率密度为 1500 W kg-1 时实现了 42.5 Wh kg-1 的高能量密度。XPS 深度剖析证实了 VO 和 Fe2+/3+ 混合价态的存在。Fe2+/3+ 和 VO 的可调氧化还原转变有助于实现更高的伪电容响应。

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引用次数: 0

Photoelectrochemical behavior of GaTe nanoflakes prepared by exfoliation 剥离法制备的 GaTe 纳米片的光电化学行为

IF 5.5 3区材料科学 Q1 ELECTROCHEMISTRY

Electrochimica Acta

Pub Date : 2024-09-21 DOI: 10.1016/j.electacta.2024.145105

Gallium telluride (GaTe), a layered semiconductor, was investigated in the photoelectrochemical (PEC) hydrogen evolution reaction (HER). GaTe nanoflakes were prepared by both mechanical and liquid phase exfoliations, and were subsequently used to obtain micro-, and macroelectrodes. When studying them as photocathodes, the highest photocurrent density of ∼6 mA cm⁻² was achieved with a 808±50 nm thick flake. Importantly, the GaTe microelectrodes presented a thickness dependent PEC activity. Macroscopic (1 cm²) GaTe electrodes were also prepared from the liquid phase exfoliated nanoflakes, by immobilizing them on glassy carbon electrodes. GaTe photocathodes showed loading and solar power flux dependent PEC activity and reaching a maximum photocurrent of ∼4 mA cm^–2 with a good photostability. Overall, these results add another candidate to the pool of photoelectrodes applicable in different PEC processes.

研究了层状半导体碲化镓（GaTe）在光电化学（PEC）氢演化反应（HER）中的应用。研究人员通过机械和液相剥离两种方法制备了碲化镓纳米片，随后用它们获得了微电极和大电极。在将它们作为光电阴极进行研究时，厚度为 808±50 nm 的薄片达到了 ∼6 mA cm-2 的最高光电流密度。重要的是，GaTe 微电极的 PEC 活性与厚度有关。通过将液相剥离的纳米薄片固定在玻璃碳电极上，还制备出了大尺寸（1 cm2）GaTe电极。GaTe 光电阴极显示出与负载和太阳能通量相关的 PEC 活性，最大光电流达到 ∼4 mA cm-2，并具有良好的光稳定性。总之，这些结果为适用于不同 PEC 过程的光电极库增添了另一种候选材料。

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