Topic Review Peer Reviewed
Reference Electrodes
A reference electrode is a half-cell (an electrode) with a stable, well-defined and highly reproducible electrode potential. A vast number of electrodes have been developed for different applications. They are briefly presented. For the common types, the advantages and drawbacks are discussed. Practical hints for daily use are provided.
  • 3.1K
  • 04 Feb 2024
Topic Review
Low-Dimensional Vanadium-Based High-Voltage Cathode Materials
Owing to their rich structural chemistry and unique electrochemical properties, vanadium-based materials, especially the low-dimensional ones, are showing promising applications in energy storage and conversion.
  • 91
  • 30 Jan 2024
Topic Review
Surfactants as Performance-Enhancing Additives in Supercapacitor Electrolyte Solutions
Wetting the surface area of an electrode material as completely as possible is desirable to achieve optimum specific capacity of an electrode material. Keeping this surface area utilized even at high current densities and even when inside small pores is required for high capacitance retention. The addition of surfactants at small concentrations to aqueous supercapacitor electrolyte solutions has been suggested as a way to improve performance in terms of capacitance, capacitance retention at increased current density and stability. Effects are pronounced with carbon materials used in electrochemical double-layer capacitors; they are also observed with redox materials. 
  • 168
  • 29 Jan 2024
Topic Review
Bismuth-Based Composites for Energy Storage Systems
Bismuth (Bi) has been prompted many investigations into the development of next-generation energy storage systems on account of its unique physicochemical properties. Although there are still some challenges, the application of metallic Bi-based materials in the field of energy storage still has good prospects. 
  • 111
  • 17 Jan 2024
Topic Review
Electrochemical Energy Storage Devices
Among electrochemical energy storage (EES) technologies, rechargeable batteries (RBs) and supercapacitors (SCs) are the two most desired candidates for powering a range of electrical and electronic devices. The RB operates on Faradaic processes, whereas the underlying mechanisms of SCs vary, as non-Faradaic in electrical double-layer capacitors (EDLCs), Faradaic at the surface of the electrodes in pseudo-capacitors (PCs), and a combination of both non-Faradaic and Faradaic in hybrid supercapacitors (HSCs). EDLCs offer high power density but low energy density. HSCs take advantage of the Faradaic process without compromising their capacitive nature. Unlike batteries, supercapacitors provide high power density and numerous charge–discharge cycles; however, their energy density lags that of batteries. Supercapatteries, a generic term that refers to hybrid EES devices that combine the merits of EDLCs and RBs, have emerged, bridging the gap between SCs and RBs. 
  • 630
  • 16 Jan 2024
Topic Review
Solid-State Batteries
Batteries are essential in modern society as they can power a wide range of devices, from small household appliances to large-scale energy storage systems. Safety concerns with traditional lithium-ion batteries prompted the emergence of new battery technologies, among them solid-state batteries (SSBs), offering enhanced safety, energy density, and lifespan. Solid-state electrolytes used in SSBs include inorganic solid electrolytes, organic solid polymer electrolytes, and solid composite electrolytes. Inorganic options like lithium aluminum titanium phosphate excel in ionic conductivity and thermal stability but exhibit mechanical fragility. Organic alternatives such as polyethylene oxide and polyvinylidene fluoride offer flexibility but possess lower ionic conductivity. Solid composite electrolytes combine the advantages of inorganic and organic materials, enhancing mechanical strength and ionic conductivity. While significant advances have been made for composite electrolytes, challenges remain for synthesis intricacies and material stability. Nuanced selection of these electrolytes is crucial for advancing resilient and high-performance SSBs.
  • 99
  • 15 Jan 2024
Topic Review
Fundamentals of CO2RR and Perovskite Oxides
An efficient carbon dioxide reduction reaction (CO2RR), which reduces CO2 to low-carbon fuels and high-value chemicals, is a promising approach for realizing the goal of carbon neutrality, for which effective but low-cost catalysts are critically important. Many inorganic perovskite-based materials with tunable chemical compositions have been applied in the electrochemical CO2RR, which exhibited advanced catalytic performance.
  • 99
  • 10 Jan 2024
Topic Review
Design and Construction of Enzyme-Based Electrochemical Gas Sensors
The demand for the ubiquitous detection of gases in complex environments is driving the design of highly specific gas sensors for the development of the Internet of Things, such as indoor air quality testing, human exhaled disease detection, monitoring gas emissions, etc. The interaction between analytes and bioreceptors can described as a “lock-and-key”, in which the specific catalysis between enzymes and gas molecules provides a new paradigm for the construction of high-sensitivity and -specificity gas sensors. The electrochemical method has been widely used in gas detection and in the design and construction of enzyme-based electrochemical gas sensors, in which the specificity of an enzyme to a substrate is determined by a specific functional domain or recognition interface, which is the active site of the enzyme that can specifically catalyze the gas reaction, and the electrode–solution interface, where the chemical reaction occurs, respectively. As a result, the engineering design of the enzyme electrode interface is crucial in the process of designing and constructing enzyme-based electrochemical gas sensors.    
  • 244
  • 05 Jan 2024
Topic Review
Zinc–Bromine Flow Batteries
The development of energy storage systems (ESS) has become an important area of research due to the need to replace the use of fossil fuels with clean energy. Redox flow batteries (RFBs) provide interesting features, such as the ability to separate the power and battery capacity. This is because the electrolyte tank is located outside the electrochemical cell. Consequently, it is possible to design each battery according to different needs. In this context, zinc–bromine flow batteries (ZBFBs) have shown suitable properties such as raw material availability and low battery cost. To avoid the corrosion and toxicity caused by the free bromine (Br2) generated during the charging process, it is necessary to use bromine complexing agents (BCAs) capable of creating complexes.
  • 164
  • 29 Dec 2023
Topic Review
Electrochemistry of Flavonoids
Three potential regions related to flavonoid structures are characteristic of the occurrence of their electrochemical oxidation regardless of the solvent used. However, the potential values depend on the solvent used.  In the less positive potential region, flavonoids, which have an ortho dihydroxy moiety, are reversibly oxidized to corresponding o-quinones. The o-quinones, if they possess a C3 hydroxyl group, react with water to form a benzofuranone derivative (II). In the second potential region, (II) is irreversibly oxidized. In this potential region, some flavonoids without an ortho dihydroxy moiety can also be oxidized to the corresponding p-quinone methides. The oxidation of the hydroxyl groups located in ring A, which are not in the ortho position, occurs in the third potential region at the most positive values.
  • 89
  • 29 Dec 2023
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