The redox active species in all-vanadium redox flow batteries (VRFBs) reside in the electrolyte, while the heterogeneous reactions occur on the electrode surface; the electrode is therefore the decisive platform for dynamic adsorption, electron transfer, and ion conversion, especially for the VO²⁺/VO₂⁺ and V²⁺/V³⁺ couples. One of the major challenges for VRFBs is the slow charge transfer in VO²⁺/VO₂⁺ and V²⁺/V³⁺ reactions, mainly caused by poor catalytic performance of electrodes and weak adhesion of catalysts to electrodes. This review focuses on the key challenges and recent advancements in VRFBs. It begins with an overview of VRFBs, including their history, working principles, applications, and the advantages and limitations associated with their use. One persistent, under-addressed trade-off is that strategies that boost apparent activity (e.g., high defect density or surface area) can degrade adhesion and cycling durability under flow shear; activity should therefore be co-reported with adhesion and durability descriptors. Addressing this trade-off is critical to improving overall efficiency and stability in VRFBs systems. A comprehensive discussion of various electrode materials is presented, categorized by their properties and preparation methods. Special emphasis is placed on the synthesis and application of carbon-based electrode materials, highlighting their potential in addressing these challenges. Finally, we map materials-level gains to stack- and system-level metrics, and outline strategies, with a focus on bifunctional and in-situ grown catalysts, for achieving high-efficiency, high-stability VRFBs.

Anodic aluminium oxide (AAO) porous films with an interpore distance of several hundred nanometers are of great interest due to their unique interaction with visible and near-infrared light, and high thermal stability up to 1500 °C. These porous films are prepared by aluminium anodizing at high voltages in weak acids, leading to a slow kinetics of initial stages of porous structure formation. Here, we propose an approach to accelerate AAO formation in electrolytes based on weak acids such as phosphoric acid. Aluminium foils, pre-patterned using first anodizing under different conditions and subsequent selective dissolution of a sacrificial AAO layer, were utilized as substrates. The morphology of the aluminium surface, including surface roughness and height of pyramidal spikes, plays a crucial role in the pore nucleation and rearrangement process during the second anodizing. In particular, by first anodizing in strong acid electrolytes at low voltages (such as 0.3 M sulfuric acid at 25 V), it is possible to double the rate of pore nucleation and subsequent reach of the steady-state regime during second anodizing in phosphoric acid. As a result, about 2 hours can be saved during the two-step anodizing process in phosphoric acid if a strong acid electrolyte is used for the first anodizing to pre-pattern aluminium surface.

Electrochemiluminescence (ECL) of luminol has been studied on a screen-printed gold electrode for a simple and sensitive detection of arsenic ions (As(III)). Cyclic voltammetry (CV) was applied as the proposed technique to study luminol's electrochemical behavior and to evaluate the arsenic’s effect in the ECL system, while hydrogen peroxide (H₂O₂) served as a co-reactant to enhance luminol’s light emission under alkaline conditions. To achieve optimal electrode performance, key parameters including pH, scan rate, and the concentrations of H₂O₂ and luminol were carefully optimized. The presence of As(III) induced a quenching effect on the luminol/H₂O₂ ECL system, leading to a linear decrease in ECL signal across the wide concentration range of 1 nmol·L^-1 to 150 µmol·L^-1. The system demonstrated a low detection limit of 1.21 nmol·L^-1 and exhibited excellent repeatability with a relative standard deviation of 2.27%, highlighting its sensitivity and reliability for As(III) detection. A key advantage of this study was the successful use of commercial bare electrodes, which were readily available and required no modifications, proving their effectiveness for ECL-based arsenic sensing. The optimized buffer solution pH of 10 played a critical role in enhancing arsenic detection selectivity, as it facilitated the optimal deprotonation of luminol and ensured arsenic remained in its dissolved state, whereas other potential metal ion interferences were more likely to form solid metal (hydro)oxides. Furthermore, the developed sensor was successfully applied for As(III) detection in a seawater matrix, demonstrating its potential as a robust and effective ECL-based arsenic sensor for environmental applications.

Redistribution Layer (RDL), composed of layered dielectrics and electroplated copper materials, is a basic structure to rearrange numerous I/O pads on the chip surface in wafer-level advanced packaging. As the key chemicals in electrolyte baths, electroplating additives have undergone continuous development to meet the industrial needs for high-speed and fine-line/fine-pitch applications. Meanwhile, the intricate relationships between additive chemical structures and electroplated copper properties are yet to be well understood. In this work, a pair of triphenylmethane-based dye molecules, i.e., gentian violet (GV) and methyl green (MG), was comparatively investigated as levelers for high-speed RDL copper electroplating. Compared to GV, significantly stronger electrochemical polarization and tunable deposit morphology can be achieved by MG with just one extra quaternized amine terminal. Combining quantum chemical computations, in situ spectroelectrochemical analyses, and microstructural characterization, it is found that MG possesses enhanced electrostatic adsorption, surface coverage and multi-additive synergies, enabling tailored copper trace morphology. This study elaborates the adsorption mechanism and screening criteria of triphenylmethane-derived levelers, and presents a candidate additive structure for high-speed copper electroplating.