Angular color shift is one of the most intuitive performa nce for display users. In this study, we designed a set of org anic light‐emitting diodes (OLED) based on ViP™ structure with different optical structures for Red (R), Green (G), and Blue (B) devices, including thickness of cathode, capping laye r (CPL), and thin film encapsulation (TFE) layers. Based on this device configuration, the angular luminance decay (L‐dec ay) and CIExy of RGB possess larger freedom for tuning the white‐light color shift By optical simulation, we demonstrate d the effect of thickness on angular L‐decay and CIExy curv es of the key optical layers in RGB devices, where the catho de, CPL, TFE exhibited different variation at different viewin g angle. Importantly, we obtained an accurate simulation mo del for forecasting the white‐light angular color shift by our correction method Owing to the ViP™ structure, we finally obtained the white‐light color shift less than 1 JNCD (@30/4/60°, which was a rarely reported result Therefore, ViP™ ba sed OLED structures exhibited great potential in application of full‐size AMOLED products with high quality display.

Proton exchange membrane water electrolysis (PEMWE) has gathered significant interest as a method for hydrogen production. A crucial step in optimizing PEMWE performance is a pre-treatment process known as “conditioning” or “break-in”, during which a voltage or current is applied to the PEMWE prior to its actual operation. Despite its importance, the underlying mechanisms and improvements achieved through conditioning remain unclear. This study investigates the effects of conditioning on PEMWE, focusing on changes in the properties of the cation exchange polymer electrolyte membrane and the IrO2 oxygen evolution catalyst. Results show that membrane conductivity increases and the valency of Ir changes from +3 to +5 by voltage application. The valency changes of Ir occur in two distinct voltage regions (0.8–1.0 and 1.3–1.5 V vs. cathode (CE)) when the applied voltage remains below the threshold for water electrolysis. Despite the intentional introduction of valence changes through applied voltage, no significant changes in the I-V characteristics within the water electrolysis region (from 1.5 to 2.0 V vs. CE) are observed. This is likely due to the fact that, at least as observed in linear sweep voltammetry, the activation time of Ir is sufficiently rapid that even the sweep rate of 10 mV/s is sufficient for activation.

Integrating anodic biomass valorization with carbon dioxide electroreduction (CO2RR) can produce value-added chemicals on both the cathode and anode; however, anodic oxidation still suffers from high overpotential. Herein, a photothermal-assisted method was developed to reduce the potential of 5-hydroxymethyl furfural (HMF) electrooxidation. Capitalizing on the copious oxygen vacancies, defective Co3O4 (D-Co3O4) exhibited a stronger photothermal effect, delivering a local temperature of 175.47 °C under near infrared light illumination. The photothermal assistance decreased the oxidation potential of HMF from 1.7 V over pristine Co3O4 to 1.37 V over D-Co3O4 to achieve a target current density of 30 mA cm-2, with 2,5-furandicarboxylic acid as the primary product. Mechanistic analysis disclosed that the photothermal effect did not change the HMF oxidation route but greatly enhanced the adsorption capacity of HMF. Meanwhile, faster electron transfer for direct HMF oxidation and the surface conversion to cobalt (oxy)hydroxide, which contributed to indirect HMF oxidation, was observed. Thus, rapid HMF conversion was realized, as evidenced by in situ surface-enhanced infrared spectroscopy. Upon coupling cathodic CO2RR with an atomically dispersed Ni-N/C catalyst, the Faradaic efficiencies of CO (cathode) and 2,5-furandicarboxylic acid (FDCA, anode) exceeded 90.0 % under a low cell potential of 1.77 V.

Rechargeable Li-ion batteries for the market of electrical vehicles, portable equipment for entertainment, computing and telecommunication surge for the past decades, but the increasing demands introduce great challenges towards future battery systems that require higher energy and power density, improved safety as well as a longer lifespan. Lithium metal batteries can deliver higher energy densities compared with commercialized LIBs but the practical applications have been hindered due to the growth of lithium dendrites in liquid lithium metal batteries. The uncontrollable dendrite leads to the repeated formation of solid electrolyte interphase, irreversible capacity loss, short circuits, and safety hazards with liquid electrolytes. Compared to liquid electrolytes, solid-state electrolytes might be a better choice, but the reliance of ionic diffusion at the contact of solid particles is crucial presenting a major challenge. Moreover, the effective use of high capacity cathodes in combination with Li metal in a solid-state battery is another big challenge for future battery development. Therefore, to unlock the full potential of LMBs with high energy density and safe operation, it is imperative to devote efforts in solid-state batteries design. This thesis aims to search effective methods for enabling safe and high-energy-density solid-state Li metal batteries, starting from the developments of new concepts in liquid-based batteries and heading for an anode less Li metal solid-state battery configuration step by step.

MnO2/C and Pd/C catalysts used for the MnO2- Pd/C gas-diffusion cathodes were prepared by redox, and characterized by transmission electronmicroscopy (TEM), X-ray photoelectron spectroscopy (XPS). The electrochemical degradation of phenol was surveyed in a diaphragm electrolysis system and a connected electrolysis system, feeding with air, making the most of four kinds of self-made gas-diffusion cathodes. It turns out the MnO2- Pd/C cathodes was better than other cathodes, and the degration efficiency reached 96.95% and 99.3% in two kinds of electrolysis systems, respectively, after reaction for 100min.

Solid oxide fuel cells (SOFCs) have attracted a lot of attention for their high efficiency, fuel flexibility, lower air pollution, etc. Unfortunately, their operating high temperature is the main shortcoming for commercialization. One of the main hurdles to achieving intermediate temperature SOFCs is the conductivity of their cathode materials at lower temperatures.Therefore, in this study, a conductive Sr_3 Fe_1.8 Co_0.2 O_7 cathode material with a Ruddlesden−Popper crystal structure was first successfully synthesized and then the effect of sintering temperature was investigated. X-ray diffraction analysis results revealed that the powder was approximately pure. Moreover, field emission scanning electron microscope (FESEM) micrographs rod-shaped particles with an average particle size of 670 nm. To evaluate the sintering effect on the electrochemical behavior of the synthesized powder, a paste of the powder was painted on both sides of the Gadolinium doped Ceria (CGO) electrolyte and sintered at 1000°C and 1100°C. The electrochemical impedance analysis on symmetrical half-cells revealed that the minimum polarization resistance for the sintered cathode at 1000°C and 1100°C was 1.1 Ω.〖cm〗^2 and 1.6 Ω.〖cm〗^2 at 800֯C. The FESEM micrograph showed High-temperature sintering could affect the interface between CGO and SFCO and decrease transport pathways for oxygen ions conduction at higher sintering temperatures. Also, the electrical conductivity of the sample was determined by the four-point probe electrical conductivity method in the temperature range of 200_800˚C at room atmosphere. The results show that the maximum electrical conductivity at 427°C is 76 S.〖cm〗^(-1).

In⁃situ Growth NiS/nickel Foam as Cathode Current Collector of Magnesium-sulfur Batteries

Vacuum arc discharges with deuteride cathode have many applications, such as nondestructive examination, oil logging, and neutron activation analysis. Deuteride cathode releases many gases during discharge, which is quite different from metal cathode. The discharges display some unique characteristics. A maguifying lens and an ICCD camera are used to observe the luminous spots of vacuum arc discharge. The space resolution of this system is about 5 μm, and the time resolution is about 2 ns. The arc current has a full width at half maximum (FWHM) of about 0.9 μs, and its waveform is half cycle sinusoidal. The results show that the luminous spots merge together into a big one in most cases. Sometimes there are two or more luminous spots due to droplets. The area of the luminous spot grows as arc current increases. The cathode spots’ merging is helpful to increase plasma density and improve discharge efficiency.

Li-rich manganese cathode material(LMCM)is considered to be the most promising cathode material for the next generation of Li-ion battery due to the advantages of high specific capacity (>250 mAh·g^-1) and low cost. However, due to factors such as irreversible structural transformation of the cathode material during cycling, these materials suffer from many problems including high first irreversible capacity loss, energy decay, poor rate performance and voltage decay. The problems of LMCM can be partially improved by lattice doping, coating modification and structural optimization design, and the electrochemical performance as a cathode material for Li-ion batteries can be improved. This paper focuses on the primary problems and modification research work of LMCM. The causes of the problems existing in LMCM were firstly analysed. Then, the current research status of the main modification methods was elaborated. Meanwhile, the advantages and disadvantages of each modification method were discussed while the future research directions were pointed out. The current industrialization process and major challenges of LMCM materials were also discussed.Due to LMCM’s problems and the slow development of supporting materials,it is only produced in small batches in a few enterprises at present.

In this thesis, the application of electrospun polyacrylonitrile-derived carbon-fibre mats as electrodes for aqueous-alkaline metal--air batteries is investigated. Three main aims are pursued: First, a deeper understanding of the morphological properties of the fibres and their transformation during carbonisation. Secondly, establishing a method of activity evaluation that allows for an analysis in near-application scenarios. Lastly, relating structural information and activity.After outlining current challenges in the field of global energy storage, the history and working principles of the aqueous-alkaline metal--air battery systems is presented. The main reactions on the air-electrode, oxygen reduction and evolution are presented and discussed in detail. Current approaches to catalyse these kinetically challenging reactions are focussed on, considering mainly nitrogen-doped carbons and co-doped carbons using transition metal catalysts. Polyacrylonitrile is a feasible base material, because of its inherent nitrogen content and behaviour during carbonisation. It was further enhanced by adding cobalt and nickel, promising oxygen electro-catalysts. A variety of methods was employed to investigate the materials, including Raman spectroscopy, XPS, XRD, and linear sweep voltammetry. The structure and composition of polyacrylonitrile-derived carbon-fibres are discussed in wide range of carbonisation temperatures. The nitrogen content was found to be more than halved between 600 °C and 1000 °C. Also, the nitrogen bonding-types evolve from mainly pyridinic nitrogen to graphitic nitrogen. This was found to influence the electrochemical performance of the material, especially the limiting current and overpotentials of the oxygen reduction reaction. The overall activity maximum was found for samples carbonised at 800 °C.The structure of the carbon material is modified in presence of cobalt and nickel. In both cases, turbostratic carbon is formed and the nitrogen removal is shifted towards lower temperatures. The nitrogen bonding is also affected, with the metals inducing a higher content of pyridinic nitrogen. The changes affect activity in terms of oxygen reduction current densities and overpotentials. While nickel was found to influence the morphology more, cobalt made a stronger impact on electrochemical activity. Neither metal, significantly influenced the oxygen evolution activity. While the presented materials are shown to function as an air-electrode and the introduced key parameters of performance description allow for a sufficient correlation of structural properties and electrochemical activity, more research is required to enhance the performance of the electrodes to a competitive level.

Study on the Uniformity of Micro-grooves in Through-Mask Electrochemical Micromachining with Moving Cathode

A review of carbon-based cathode materials for zinc-ion capacitors

Disposal of conventional polymer-based electrodes and capacitor can cause pollutions or incur high cost. More carbon based nanosheet electrode is more environmental friendly. Novel supercapacitors were fabricated using carbon nanosheet electrode. Two pieces of thick layer carbon nanosheet electrodes were used as the cathode; the anode were made of carbon nanosheet and graphite mixture with a ratio of 7: 3, 10 % binder and coated on top of a glass surface. The polymer gel electrolytes containing barium carbonate (BaCO3) or calcium carbionate (CaCO3) were filled in the middle of the electrodes to act as a supercapacitor. The concentrations of electrolytes, BaCO3 and CaCO3 were 10 %; 20 %; 30 %. The performance of the supercapacitors was determined by cyclic voltammetry, and charge-discharge galvanostatic methods performed using a potentiostat. The decreasing in capacitances occurred along with the increase of scan rate, from 5 mV s-1 to 100 mV s-1. There is only a slight decrease in the first cycle, as shown by the increased slope of 20 % CaCO3 of supercapacitor. The first cycle plot shows the existence of linearity both in the direction of charging and discharging. All supercapacitors have the same slope value indicating the same rate for both charging and discharging process. Except for the supercapacitor with 20 % CaCO3 where different slope values were observed for its charging and discharging rate, i.e., 1.345 and -1.344. The result showed that the supercapacitor has a charging rate faster than its discharging rate. The cyclic voltammetry tests showed that the highest value of 6.95 mF g-1 was achieved using the supercapacitor of 10 % CaCO3 as electrolyte; or 3.91 mF g-1 with 10 % BaCO3. A novel supercapacitor, using carbon nanosheets derived from aquatic wood waste as eletrodes and polymer-based gel as electrolytes, was developed.

The extensive usage of portable electronic products and the acceleration of their replacement have led to the discarding of a growing amount of LiCoO2 batteries. It is necessary to recycle the batteries from the both viewpoints of environment and economic benefits. Current recycling approaches for LiCoO2 are dominantly based on hydrometallurgy and pyrometallurgy, which usually require multiple complicated steps and involve the use of high temperature or harmful chemicals, like acids and alkalis. There remains an urgent need for a green and simple process. In this paper, suspension electrolysis technology is proposed to recycle spent batteries, in order to achieve the leaching, purification and regeneration of LiCoO2 in one step. The most advantageous of the present technology are that reacting in one reactor at atmospheric condition and no use of highly corrosive and harmful reagents. The reaction of LiCoO2 leaching in the anode region and simultaneously re-synthesizing in the cathode region in ammonia electrochemical system is established for the first time. This work provides a promising method for recovering LiCoO2 efficiently and environmentally friendly, promoting the sustainable utilization of the resources.

Quick identification of internal resistance components for lithium ion battery with LiFePO 4 cathode

An Efficient Macroporous Catalytic Cathode for Li-S Battery

Aqueous zinc ion batteries (ZIBs) are the most promising rechargeable batteries for the grid energy storage and industrial energy storage for its lower cost and higher safety. There are three main problems, which are the major obstacle to the development of ZIBs. One is the cathode electrode and finding a suitable cathode material is the foundation to solve above problem. The cathode materials consist of Mn-based materials, V-based materials, Prussian blue analogous (PBAs), Quinone and the others materials. The second is the reaction mechanisms of Zn2+ ions storage in ZIBs. The third is the improving reaction kinetics of insertion and diffusion of Zn2+ in the cathode materials. Read more in the Review by J. Liu et al. on page 830.

Methods of investigating structural evolution and interface behavior in cathode materials for Li-ion batteries

Natural Quinone Molecules as Effective Cath Ode Materials for Lithium-Ion Batteries: A First-Principles Study

Enhanced the electrochemical performances of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode by ZrO2 coating