Implications of electrode modifications in aqueous organic redox flow batteries

Aqueous organic redox flow batteries(RFBs)exhibit favorable characteristics,such as tunability,multielectron transfer capability,and stability of the redox active molecules utilized as anolytes and catholytes,making them very viable contenders for large-scale grid storage applications.Considerable attention has been paid on the development of efficient redox-active molecules and their performance optimization through chemical substitutions at various places on the backbone as part of the pursuit for high-performance RFBs.Despite the fact that electrodes are vital to optimal performance,they have not garnered significant attention.Limited research has been conducted on the effects of electrode modifications to improve the performance of RFBs.The primary emphasis has been given on the impact of electrode engineering to augment the efficiency of aqueous organic RFBs.An overview of electron transfer at the electrode-electrolyte interface is provided.The implications of electrode modification on the performance of redox flow batteries,with a particular focus on the anodic and cathodic half-cells separately,are then discussed.In each section,significant discrepancies surrounding the effects of electrode engineering are thoroughly examined and discussed.Finally,we have presented a comprehensive assessment along with our perspectives on the future trajectory.

Electrode Modifications for Polymer Light-Emitting Electrochemical Cells

The influence of different modification methods on the surface properties of indium-tin-oxide (ITO) electrodes were investigated by measurements of chemical composition,surface roughness,sheet resistance,contact angle and surface free energy.Experimental results demonstrate that oxygen plasma treatment more effectively optimizes the surface properties of ITO electrodes compared with the other treatments.Furthermore,the polymer light-emitting electrochemical cells (PLECs) with the differently treated ITO substrates as device electrodes were fabricated and characterized.It is found that oxygen plasma treatment on the ITO electrode enhances injection current,luminance and efficiency,thereby improves the device characteristics of the PLECs.

Surface Modification of AB_2 and AB_5 Hydrogen Storage Alloy Electrodes by the Hot-Charging Treatment

The effect of the hot-charging treatment on the performance of AB(2) and AB(5) hydrogen storage alloy electrodes was investigated. The result showed that the treatment can markedly improve the voltage plateau ratio (VPR), the high rate discharge ability (HRDA), the diffusion coefficient of hydrogen DH and the discharge capacity of the AB2 hydrogen storage alloy electrode. The SEM analysis showed that the hot-charging treatment brings about a Ni-rich surface due to the dissolution of Zr oxides. It is also very helpful for the improvement of the kinetic properties of AB2 hydrogen storage alloy electrode because the microcracking of the surface results in fresh surface. This can be the basic modification treatment for NiMH battery used in electric vehicles (EVs) in the future. But for AB(5) type alloys, the treatment has the disadvantage of impairing the comprehensive electrochemical properties, because the surface of the alloy may be corroded during the treatment. The mechanism of the surface modification of the electrode is also proposed.

Synthesis and modification of nanowires anchored on electrodes for electrochemical and electrophysical applications

The integration of nanowires onto electrode surfaces marks a significant advancement over traditional electrode materials,conferring upon nanowire-modified electrodes a vast array of applications within electrochemical and electrophysical domains.The nanowires used for electrode modification can be catalogized into two distinct types:anchored nanowires and free-standing nanowires.A critical advantage of anchored nanowires lies in their enhanced electrical connectivity with the substrate,which reduces electrode resistance and facilitates charge transport.Furthermore,the anchorage of nanowires onto electrodes provides additional mechanical support,bolstering the structural stability of the nanowire assembly.Here,we review the development of anchored nanowires designed for applications in energy storage,electrocatalysis,and electric field treatment(EFT)over the past decade.We focus on the synthesis and modification strategies employed for anchored nanowires,culminating in the evaluation of these fabrication and enhancement techniques.Through this analysis,we aim to furnish comprehensive insights into the preparation of anchored nanowires,guiding the selection of appropriate fabrication processes and subsequent functional modifications.

Enhancing electrochemical performance of SnO_(2) anode with humic acid modification

Humic acid(HA)was studied as a modifier in the SnO_(2) anode preparation for the electrochemical performance improvement.Scanning electron microscopy,180°peel test,and nanoindentation experiment were used to examine the influence of the HA on electrode.The results showed that the addition of HA could improve the dispersion uniformity of all particles.The components were tightened,increasing the difficulty of peeling off the film from the current collector.The deformation resistance of the electrode was greatly enhanced by the HA modification.The electrochemical test results showed that the anode from the normal micron-sized SnO_(2)particles with the HA modifier exhibited significant progress in electrochemical performance compared with those without HA.The reversible specific capacity of the SnO_(2) anode can be maintained as high as 733.4 mA·h/g at a current density of 100 mA/g after 50 cycles.Therefore,HA is a promising modifier for anode preparation of lithium-ion batteries.

Fundamental Understanding and Effect of Anionic Chemistry in Zinc Batteries

With the merit of high capacity,high safety,and low cost,zinc-ion batteries(ZIBs)possess huge application potential in the domain of large-scale energy storage.However,due to the relatively narrow voltage window and large lattice distortion of cationic redox reaction,ZIBs tend to present low energy density,poor kinetics,and unstable cyclic performance.Anion chemistry seems to provide a novel strategy to solve these issues from different aspects,such as enhanced operating voltage,extra capacity contribution,and boosted reaction kinetics.Considering the significance of this theory and the lack of relevant literatures,herein,in-depth comprehension of anionic chemistry and its positive effects on zinc storage performance have been emphasized and summarized.This review aims to present a full scope of anionic chemistry and furnish systematic cognition for rational design of advanced ZIBs with high energy density.Furthermore,insightful analysis and perspectives based on the current research status also have been proposed,which may point out some scientific suggestions and directions for the future research.

Study on Glow Discharge Plasma Used in Polyester Surface Modification

To achieve an atmospheric pressure glow discharge（APGD）in air and modify the surface of polyester thread using plasma,the electric field distribution and discharge characteristics under different conditions were studied.We found that the region with a strong electric field,which was formed in a tiny gap between two electrodes constituting a line-line contact electrode structure,provided the initial electron for the entire discharge process.Thus,the discharge voltage was reduced.The dielectric barrier of the line-line contact electrodes can inhibit the generation of secondary electrons.Thus,the transient current pulse discharge was reduced significantly,and an APGD in air was achieved.We designed double layer line-line contact electrodes,which can generate the APGD on the surface of a material under treatment directly.A noticeable change in the surface morphology of polyester fiber was visualized with the aid of a scanning electron microscope（SEM）.Two electrode structures-the multi-row line-line and double-helix line-line contact electrodes-were designed.A large area of the APGD plasma with flat and curved surfaces can be formed in air using these contact electrodes.This can improve the efficiency of surface treatment and is significant for the application of the APGD plasma in industries.

Progress of organic,inorganic redox flow battery and mechanism of electrode reaction

With the deployment of renewable energy and the increasing demand for power grid modernization,redox flow battery has attracted a lot of research interest in recent years.Among the available energy storage technologies,the redox flow battery is considered the most promising candidate battery due to its unlimited capacity,design flexibility,and safety.In this review,we summarize the latest progress and improvement strategies of common inorganic redox flow batteries,such as vanadium redox flow batteries,iron-chromium redox flow batteries,and zinc-based redox flow batteries,including electrolyte,membrane,electrode,structure design,etc.In addition,we introduce the latest progress in aqueous and non-aqueous organic redox flow batteries.We also focus on the modification mechanism,optimization design,improvement strategy,and modeling method of the redox flow battery reaction.Finally,this review presents a brief summary,challenges,and perspectives of the redox flow battery.

Interfacial engineering of printable bottom back metal electrodes for full-solution processed flexible organic solar cells

Printing of metal bottom back electrodes of flexible organic solar cells（FOSCs） at low temperature is of great significance to realize the full-solution fabrication technology. However, this has been difficult to achieve because often the interfacial properties of those printed electrodes, including conductivity, roughness, work function,optical and mechanical flexibility, cannot meet the device requirement at the same time. In this work, we fabricate printed Ag and Cu bottom back cathodes by a low-temperature solution technique named polymer-assisted metal deposition（PAMD） on flexible PET substrates. Branched polyethylenimine（PEI） and ZnO thin films are used as the interface modification layers（IMLs） of these cathodes. Detailed experimental studies on the electrical, mechanical, and morphological properties, and simulation study on the optical properties of these IMLs are carried out to understand and optimize the interface of printed cathodes. We demonstrate that the highest power conversion efficiency over 3.0% can be achieved from a full-solution processed OFSC with the device structure being PAMDAg/PEI/P3 HT：PC61BM/PH1000. This device also acquires remarkable stability upon repeating bending tests.

Modification of screen-printed gold electrode with 1,4-dithiothreitol: application to sensitive voltammetric determination of Sudan Ⅱ

Objectives:The aim of this study is to investigate the electrochemical behavior of Sudan Ⅱ(Sull)using a screen-printed gold electrode(SPGE)modified with 1,4-dithiothreitol(DTT)and to determine the amount of Sudan II by voltammetry.Materials and Methods:A DTT-modified screen-printed gold electrode(DTT/SPGE)was fabricated and its application for differential pulse voltammetric(DPV)determination of Sull was reported.Fourier transform infrared spectroscopy(FT-IR),cyclic voltammetry and electrochemical impedance spectroscopy were used for the characterization of the modified electrode.The effects of instrumental and chemical parameters were optimized for the determination of Sull.The fabricated electrode was used for the analysis of Sull in fortified and real samples.High-performance liquid chromatography was preferred as a reference method for the evaluation of the obtained voltammetric results.Results:The electrochemical studies and FT-IR demonstrated that the SPGE was modified with DTT.The obtained peak current at DTT/SPGE was 6.67 times higher than that recorded with SPGE.At the optimized conditions of DPV in pH=2.5 of H2S04,the oxidation peak current of Sull was proportional to its concentration in:0.001-1.500 μmol L^(-1) with a detection limit of 0.0002 μmol L^(-1)(S/N=3).For the analysis of Sull,101.67%-104.33%of recovery percentage was obtained.Conclusions:A new electrode was successfully improved for the determination of Sull.This highly selective and sensitive electrode supplied the fast determination of Sull in ketchup,chili sauce and salsa dip sauce.In addition,voltammetric and chromatographic results are found to be consistent.