ChemElectroChem最新文献

Sodium-ion batteries (NIBs) have gained significant attention in recent years due to the global abundance and cost-effectiveness of sodium, making them a promising alternative to lithium-based batteries. In this study, nitrogen-doped graphene oxide powders (NGO) have been prepared in one step by using chronoamperometric method and then have been used as anode materials for NIBs. The NGO powder surface is covalently doped by C−N formation. The synthesized powder had few layers (~3 layers) with nanocrystalline domain size (Lα) ~46 nm, and the number of sp² carbon rings was calculated to be ~18. The initial discharge capacity recorded 199.8 mAh g⁻¹ at 0.1 C rate. Besides, the capacity retention for long-term cycling of 100 cycles at 2 C rate was 91.78 %. The deduced diffusion coefficient from galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) measurements for NGO as anode in NIBs is in the range of 10⁻¹¹–10⁻¹² cm² s⁻¹. The electrochemical performance was attributed to the enhanced d-spacing of NGO up to 6.8 °A and formation large number of defects.

Lithium metal, recognized for its extremely low reaction potential and ultrahigh theoretical specific capacity, is regarded as the “Holy Grail” of anode materials. However, the formation of lithium dendrites result in rapid cell capacity degradation and considerable safety issues, hindering its further advancement. In this study, in situ Mg seeds are generated on the lithium metal surface during cycling by incorporating MgCl₂ into the electrolyte. These Mg seeds function as thiophilic sites, which lower the Li nucleation barrier and promote uniform Li nucleation and growth. Consequently, symmetric cells constructed with the carbonate electrolyte can cycle stably for over 400 h at a current density of 1 mA cm⁻² and a capacity of 1 mAh cm⁻². Notably, full cells using Li₄Ti₅O₁₂ as the cathode can maintain stable cycling for 300 cycles, achieving a capacity retention rate of 71.9 %. This method has demonstrated its effectiveness in mitigating lithium dendrites formation and enhancing the performance of lithium metal batteries.

Electrocatalytic CO₂ reduction (CO₂R) offers a promising pathway for closing the carbon cycle. Metallic Cu-based catalysts are the only materials capable of converting CO₂ to C₂₊ products with significant selectivity and activity. Achieving industrially relevant current densities in CO₂R requires the use of gas diffusion electrodes (GDEs), making the structure and properties of the catalyst layer (CL) on GDEs critical to the CO₂R performance of Cu catalysts. However, limited research has explored how catalyst ink composition affects CL features and, consequently, CO₂R performance under operating conditions. In this study, we investigate the influence of catalyst ink composition on CL structure and morphology, and how these properties affect CO₂R performance. We find that the water content in the ink modifies active site density, thickness, and porosity of the CL, as well as the state of the Nafion binder, thereby altering the microenvironment of the active sites during CO₂R, including local CO₂ concentration and pH. Our results reveal a strong correlation between CO₂R performance and the structural characteristics of the CL. Specifically, optimizing the ethanol-to-water ratio in the catalyst ink enhances C₂₊ product selectivity and current density to 75 % and 450 mA cm⁻², respectively. This approach provides a simple yet effective strategy to improve CO₂R activity and selectivity under practical conditions.

Lithium-ion batteries (LIBs) are one of the most advanced electrochemical energy storage technologies. However, the increasing demand for LIBs, coupled with problems related to availability and lack of manufacturing centers, has led to lithium market inflation. At this point, sodium-ion batteries (SIB) represent an economically and environmentally attractive alternative for LIBs. Prussian Blue cathodes (PB) have been extensively studied as cost-effective materials with volumetric variations that allow the accommodation of sodium ions in the structure. Herein, we present a quasi-solid Na-ion cell based on PB cathode and green gel polymer electrolyte (GPE). Nanometric and micrometric PB powders are synthesized and characterized using a wide variety of structural, compositional and electrochemical techniques. The effect of the PB particle size in combination with different electrolytes is investigated. Enhanced cell safety is obtained using a GPE prepared by following a novel green method that avoids using toxic organic solvents. All the tested cells report remarkable electrochemical performance, being the nanometric-PB/ GPE/ Na cell configuration the one with the highest specific capacity and almost no capacity loss after 100 cycles, outperforming analogous cells assembled with liquid electrolyte. This electrochemical stability is triggered by a robust electrode-electrolyte interphase.

Cover image provided courtesy of Nongnoot Wongkaew and Antonia Perju.

In silicon/graphite (Si/Gr) composite electrodes for lithium-ion batteries, which have recently garnered significant attention, the competitive (de)lithiation between Si and Gr is recognized as crucial for understanding the internal electrochemical processes. In this work, an in-situ method to characterize this competitive behavior is proposed, utilizing a self-developed electrode curvature measurement system. After validating the parallel electrode configuration and the model battery, curvature measurements are simultaneously conducted on the parallel Si and Gr cantilevered electrodes throughout electrochemical cycling. Subsequently, by calibrating the correlation between capacity and curvature of the Gr electrode, the capacity evolution of Si and Gr within the Si/Gr electrode is determined, shedding light on the underlying competitive (de)lithiation behavior. During lithiation, the process transitions from “Si-dominant” to “Gr-dominant” and eventually reaching a “synchronous” stage. For delithiation, it moves from “Gr-dominant” to “Si-dominant”. The method proposed in this work, based on the measurement of macroscopic electrode deformation, offers a novel perspective for characterizing competitive (de)lithiation in electrodes with multiphase active materials.

Due to its sustainable approach, biomass is the subject of much research focused on the synthesis of multifunctional materials including electrodes for batteries and supercapacitors. In this work, sawdust from the processing of birch logs was used to produce a highly porous carbon material (CBW) that is employed for the construction of electrodes for aluminum batteries (ABs) and supercapacitors (SCs). A multitude of characterizations indicated that CBW is built in with highly disordered amorphous carbons and an extremely high specific surface area of 3029 m² g⁻¹ which is predominant with microporous features. The chemical analysis of CBW indicated the presence of a significant amount of oxygen functionalities. As a cathode of AB, CBW achieved discharge capacities 115, 74, 54, 50, 47, 43, and 29 mAh g⁻¹ at current rates 0.1, 1.0, 2.0, 3.0, 4.0, 5.0, and 10.0 A g⁻¹, respectively. Similarly, SC with CBW symmetric electrodes exhibited capacitances 143, 94, 87, 79, 74, 69, 65, and 51 F g⁻¹ at current rates 0.1, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, and 10.0 A g⁻¹, respectively. The electrochemical characterization revealed that CBW is promising for ABs and SCs, and controlling the porosity type could further enhance the performance.

Ni-based alloys have excellent corrosion resistance and are widely used in the petrochemical industry. In this study, the effect of sulfuric acid on the corrosion resistance of Ni was analyzed by electrochemical tests and theoretical studies in the absence and presence of 2-([(1E)-(2-hydroxyphenyl)methylene]amino)benzoic acid (H2 L). Sulfuric acid's corrosive effect, notably in fertilizer production, poses challenges for materials like nickel used in storage and transport. Discussion of nickel corrosion which is frequently used to handle sulfuric acid is given in this paper. The corrosion behavior of nickel (Ni) metal and the inhibitory effect of 2-([(1E)-(2-hydroxyphenyl)methylene]amino)benzoic acid (H₂L) were investigated using a combination of electrochemical and computational approaches. In this study, 0.5 M sulfuric acid served as the corrosive medium. The inhibitory effect of H₂L was evaluated using Tafel plots and electrochemical impedance spectroscopy. Results show a gradual decrease in the corrosion current density (I_corr.) over time, accompanied by an increase in inhibition efficiency, attributed to rising additive concentrations. The maximum inhibition efficiency (η=97.8 %) was achieved at 1×10⁻⁵ M additive concentration and 25 °C. The additive predominantly affects the anodic reaction compared to the cathodic reaction and reduces NiO formation on electrode surfaces. Increasing solution temperature enhances inhibition efficiency, indicating chemisorption following the Langmuir model, supported by electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) analysis confirms that H2 L inclusion significantly enhances nickel corrosion resistance. Charge-discharge processes of Ni were studied in 0.5 M H₂SO₄ containing various dosages of the additive at applied distinct current densities. It is interesting to note that both discharging time and specific capacitance rises with raising the applied current density at each dosage of additive in 0.5 M H₂SO₄. The most enhancements were obtained at presence of 1×10⁻⁵ M of the additive, as corrosion resistance and specific capacitance (0.391 mAh at 90 mA cm⁻²). Also, improved power and energy features are obtained in the presence of this concentration of the additive. Theoretical Density Functional Theory (DFT) studies reveal that H₂L possesses a low ΔE_gap, facilitating chemical adsorption during the inhibition process, underlining the innovative nature of this corrosion inhibition strategy. Furthermore, the H₂L−Ni interaction was effectively simulated using the DFT/B3LYP/6-311+G**, providing valuable insights into the compound's corrosion inhibition capabilities.

Recent advancements in inorganic solid electrolytes (ISEs), achieving sodium (Na)-ion conductivities exceeding 10 ^-2 S cm^-1 at room temperature (RT), have generated significant interest in the development of solid-state sodium batteries (SSSBs). However, the ISEs face challenges such as their limited electrochemical stability windows (ESWs) and compatibility issues with high-capacity, high-voltage cathode materials and Na metal anodes. The success of high-performance SSSBs hinges on developing ideal ISEs that deliver high Na⁺ ion conductivities, robust chemical and electrochemical stability, and well constructed electrode/ISE interfaces. This review explores the fundamental principles and strategies to optimize SSSB performance by addressing issues related to ISEs and their interfaces, emphasizing that many interfacial challenges are intrinsically linked to ISE properties. It highlights recent advancements in ISE research, including the mechanisms of Na-ion conduction and the key factors influencing it, such as crystal structure, lattice dynamics, point defects, and grain boundaries. It also discusses prototyping strategies for cell design from the perspectives of material and defect chemistry. Additionally, the review identifies key challenges and future opportunities for advancing SSSBs and provides rational solutions to guide future research toward the practical realization of high-performance SSSBs.

Keywords: Solid-state sodium batteries; Inorganic solid electrolytes; Interfacial mechanism; Electrochemical stability window; Ionic conductivity; Modification strategies

Polyphenol or multihydroxybenzene compounds show great potential as electrode material for organic batteries. Among them, 1,2,3,4-tetrahydroxybenezene is the best candidate as a high-specific capacity material due to its potential to exchange up to four electrons. To further corroborate this, we synthesized a model compound and carry out electrochemical characterization. Quasi-reversible redox behavior, similar to other hydroxybenzene materials, was obtained in an acidic aqueous electrolyte. The four electron exchange was further confirmed by using reduced and oxidized model compounds, which showed comparable electrochemical behavior. Additionally, we prepared insoluble nano sized polymer based on poly(2,3,4,5-tetrahydroxystyrene) which was used as a cathode material in an organic battery. Initial results suggested that these tetrahyroxybenzene polymers are very promising for proton batteries in acidic aqueous electrolytes, whereas their performance in lithium batteries is limited.