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Open AccessArticle

Light in Electrochemistry

by

Hiroya Abe

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Tomoki Iwama

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Yuanyuan Guo

Electrochem 2021, 2(3), 472-489; https://doi.org/10.3390/electrochem2030031 - 26 Aug 2021

Viewed by 196

Abstract

Electrochemistry represents an important analytical technique used to acquire and assess chemical information in detail, which can aid fundamental investigations in various fields, such as biological studies. For example, electrochemistry can be used as simple and cost-effective means for bio-marker tracing in applications, [...] Read more.

Electrochemistry represents an important analytical technique used to acquire and assess chemical information in detail, which can aid fundamental investigations in various fields, such as biological studies. For example, electrochemistry can be used as simple and cost-effective means for bio-marker tracing in applications, such as health monitoring and food security screening. In combination with light, powerful spatially-resolved applications in both the investigation and manipulation of biochemical reactions begin to unfold. In this article, we focus primarily on light-addressable electrochemistry based on semiconductor materials and light-readable electrochemistry enabled by electrochemiluminescence (ECL). In addition, the emergence of multiplexed and imaging applications will also be introduced. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Synthesis of Nickel Fumarate and Its Electrochemical Properties for Li-Ion Batteries

by

Shahul A. Hameed

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Shaikshavali Petnikota

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Electrochem 2021, 2(3), 439-451; https://doi.org/10.3390/electrochem2030029 - 27 Jul 2021

Viewed by 390

Abstract

Metal–organic frameworks (MOFs) have found a potential application in various domains such as gas storage/separation, drug delivery, catalysis, etc. Recently, they have found considerable attention for energy storage applications such as Li- and Na-ion batteries. However, the development of MOFs is plagued by [...] Read more.

Metal–organic frameworks (MOFs) have found a potential application in various domains such as gas storage/separation, drug delivery, catalysis, etc. Recently, they have found considerable attention for energy storage applications such as Li- and Na-ion batteries. However, the development of MOFs is plagued by their limited energy density that arises from high molecular weight and low volumetric density. The choice of ligand plays a crucial role in determining the performance of the MOFs. Here, we report a nickel-based one-dimensional metal-organic framework, NiC₄H₂O₄, built from bidentate fumarate ligands for anode application in Li-ion batteries. The material was obtained by a simple chimie douce precipitation method using nickel acetate and fumaric acid. Moreover, a composite material of the MOF with reduced graphene oxide (rGO) was prepared to enhance the lithium storage performance as the rGO can enhance the electronic conductivity. Electrochemical lithium storage in the framework and the effect of rGO on the performance have been investigated by cyclic voltammetry, galvanostatic charge–discharge measurements, and EIS studies. The pristine nickel formate encounters serious capacity fading while the rGO composite offers good cycling stability with high reversible capacities of over 800 mAh g⁻¹. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

A Disposable Saliva Electrochemical MIP-Based Biosensor for Detection of the Stress Biomarker α-Amylase in Point-of-Care Applications

by

Tânia S. C. R. Rebelo

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Electrochem 2021, 2(3), 427-438; https://doi.org/10.3390/electrochem2030028 - 26 Jul 2021

Cited by 1 | Viewed by 500

Abstract

The design and synthesis of artificial receptors based on molecular imprinting (MI) technology for the development of a new MIP-based biosensor for detection of the stress biomarker α-amylase in human saliva in point-of-care (PoC) applications is described in this work. The portable electrochemical [...] Read more.

The design and synthesis of artificial receptors based on molecular imprinting (MI) technology for the development of a new MIP-based biosensor for detection of the stress biomarker α-amylase in human saliva in point-of-care (PoC) applications is described in this work. The portable electrochemical devices for monitoring α-amylase consists of cost-effective and disposable gold screen-printed electrodes (AuSPEs). To build the electrochemical device, the template biomolecule was firstly immobilized directly over the working area of the gold chip previously activated with a self-assembled monolayer (SAM) of cysteamine (CA). Then, pyrrole (Py) monomer was selected as building block of a polymeric network prepared by CV electropolymerization. After the electropolymerization process, the enzyme was removed from the polymer film in order to build the specific recognition sites for the target enzyme. The MIP biosensor showed a very wide linear concentration range (between 3.0 × 10⁻⁴ to 0.60 mg mL⁻¹ in buffer solution and between 3.0 × 10⁻⁴ to 3.0 × 10⁻² mg mL⁻¹ in human saliva) and low detection levels were achieved (LOD < 3.0 × 10⁻⁴ mg mL⁻¹) using square wave voltammetry (SWV) as the electroanalytical technique. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Reduction of Cd(II) Ions in the Presence of Tetraethylammonium Cations. Adsorption Effect on the Electrode Process

by

Juan Torrent-Burgués

Electrochem 2021, 2(3), 415-426; https://doi.org/10.3390/electrochem2030027 - 23 Jul 2021

Viewed by 353

Abstract

The effect of the adsorption of tetraethylammonium (TEA) cations, which present both ionic and organic characteristics, on the reduction of Cd(II) ions have been studied from dc and ac measurements at the dropping mercury electrode. The resistance to the charge transfer (Rct) and [...] Read more.

The effect of the adsorption of tetraethylammonium (TEA) cations, which present both ionic and organic characteristics, on the reduction of Cd(II) ions have been studied from dc and ac measurements at the dropping mercury electrode. The resistance to the charge transfer (Rct) and Warburg coefficient (σ) parameters have been determined through impedance measurements. Thus, the global velocity constant has been obtained. The reduction process of Cd(II) in perchloric media is reversible and is affected by the adsorption of TEA cations, especially at high TEA concentrations. Values of E_1/2, half wave potential, and D_O, diffusion coefficient, obtained from both dc and ac measurements agree. The velocity constants show a decrease as TEA concentration increases, with values ranging from 0.6 to 0.01 cm·s⁻¹. The inhibitory effect of TEA adsorption on the electrode process and the relationship between electrode coverage, θ, and velocity constants, K, using several isotherm equations, have been discussed. The best fit was obtained with the equation K = ₀K(1 − θ)^a with an a value close to three, indicating a blocking effect and electrostatic repulsion due to TEA. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Synergistic Effect of Polymorphs in Doped NaNi_0.5Mn_0.5O₂ Cathode Material for Improving Electrochemical Performances in Na-Batteries

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Electrochem 2021, 2(2), 335-346; https://doi.org/10.3390/electrochem2020024 - 04 Jun 2021

Viewed by 754

Abstract

Layered NaNi_0.5Mn_0.5O₂, employed as cathode materials in sodium ion batteries, is attracting interest due to its high working potential and high-capacity values, thanks to the big sodium amount hosted in the lattice. Many issues are, however, related [...] Read more.

Layered NaNi_0.5Mn_0.5O₂, employed as cathode materials in sodium ion batteries, is attracting interest due to its high working potential and high-capacity values, thanks to the big sodium amount hosted in the lattice. Many issues are, however, related to their use, particularly, the complex phase transitions occurring during sodium intercalation/deintercalation, detrimental for the structure stability, and the possible Mn dissolution into the electrolyte. In this paper, the doping with Ti, V, and Cu ions (10% atoms with respect to Ni/Mn amount) was used to stabilize different polymorphs or mixtures of them with the aim to improve the capacity values and cells cyclability. The phases were identified and quantified by means of X-ray powder diffraction with Rietveld structural refinements. Complex voltammograms with broad peaks, due to multiple structural transitions, were disclosed for most of the samples. Ti-doped sample has, in general, the best performances with the highest capacity values (120 mAh/g at C/10), however, at higher currents (1C), Cu-substituted sample also has stable and comparable capacity values. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Understanding the Effect of Zn Doping on Stability of Cobalt-Free P2-Na_0.60Fe_0.5Mn_0.5O₂ Cathode for Sodium Ion Batteries

by

Devendrasinh Darbar

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M. V. Reddy

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Indranil Bhattacharya

Electrochem 2021, 2(2), 323-334; https://doi.org/10.3390/electrochem2020023 - 02 Jun 2021

Viewed by 817

Abstract

In this work, we report a sol-gel synthesis-based Zn-doped Na_0.6Fe_0.5Mn_0.5O₂ (NFM) cathode and understand the effect of Zn doping on the crystal structure and electrochemical performances such as discharge capacity and rate capability. Detailed X-Ray diffraction [...] Read more.

In this work, we report a sol-gel synthesis-based Zn-doped Na_0.6Fe_0.5Mn_0.5O₂ (NFM) cathode and understand the effect of Zn doping on the crystal structure and electrochemical performances such as discharge capacity and rate capability. Detailed X-Ray diffraction (XRD) pattern analysis indicated a decrease in the Na-layer thickness with Zn doping. Small amount of Zn²⁺ dopant (i.e., 2 at.%) slightly improved cycling stability, reversibility, and rate performances at higher discharge current rates. For example, at 1 C-rate (1 C = 260 mAh/g), the Zn²⁺-doped cathode retained a stable reversible capacity of 72 mAh/g, which was ~16% greater than that of NFM (62 mAh/g) and showed a minor improvement in the capacity retention of 60% compared to 55% for the pristine NFM after 65 cycles. Slight improvement in the electrochemical performance for the Zn-doped cathode can be attributed to a better structural stability, which prevented the initial phase transition and showed the presence of electrochemical active Fe^3+/4+ even after 10 cycles compared to NFM. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Characterization and Electrocatalytic Performance of Molasses Derived Co-Doped (P, N) and Tri-Doped (Si, P, N) Carbon for the ORR

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Electrochem 2021, 2(2), 311-322; https://doi.org/10.3390/electrochem2020022 - 02 Jun 2021

Viewed by 820

Abstract

There is a growing need to develop sustainable electrocatalysts to facilitate the reduction of molecular oxygen that occurs at the cathode in fuel cells, due to the excessive cost and limited availability of precious metal-based catalysts. This study reports the synthesis and characterization [...] Read more.

There is a growing need to develop sustainable electrocatalysts to facilitate the reduction of molecular oxygen that occurs at the cathode in fuel cells, due to the excessive cost and limited availability of precious metal-based catalysts. This study reports the synthesis and characterization of phosphorus and nitrogen co-doped carbon (PNDC) and silicon, phosphorus, and nitrogen tri-doped carbon (SiPNDC) electrocatalysts derived from molasses. This robust microwave-assisted synthesis approach is used to develop a low cost and environmentally friendly carbon with high surface area for application in fuel cells. Co-doped PNDC as well as tri-doped SiPNDC showed Brunauer–Emmet–Teller (BET) surface areas of 437 and 426 m² g⁻¹, respectively, with well-developed porosity. However, examination of X-ray photoelectron spectroscopy (XPS) data revealed significant alteration in the doping elemental composition among both samples. The results obtained using rotating disk electrode (RDE) measurements show that tri-doped SiPNDC achieves much closer to a 4-electron process than co-doped PNDC. Detailed analysis of experimental results acquired from rotating ring disk electrode (RRDE) studies indicates that there is a negligible amount of peroxide formation during ORR, further confirming the direct-electron transfer pathway results obtained from RDE. Furthermore, SiPNDC shows stable oxygen reduction reaction (ORR) performance over 2500 cycles, making this material a promising electrocatalyst for fuel cell applications. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Efficient Electrocatalytic Approach to Spiro[Furo[3,2-b]pyran-2,5′-pyrimidine] Scaffold as Inhibitor of Aldose Reductase

by

Michail N. Elinson

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Anatoly N. Vereshchagin

,

Yuliya E. Ryzhkova

,

Fedor V. Ryzhkov

,

Artem N. Fakhrutdinov

and

Mikhail P. Egorov

Electrochem 2021, 2(2), 295-310; https://doi.org/10.3390/electrochem2020021 - 25 May 2021

Viewed by 835

Abstract

A continuously growing interest in convenient and ‘green’ reaction techniques encourages organic chemists to elaborate on new synthetic methodologies. Nowadays, organic electrochemistry is a new useful method with important synthetic and ecological advantages. The employment of an electrocatalytic methodology in cascade reactions is [...] Read more.

A continuously growing interest in convenient and ‘green’ reaction techniques encourages organic chemists to elaborate on new synthetic methodologies. Nowadays, organic electrochemistry is a new useful method with important synthetic and ecological advantages. The employment of an electrocatalytic methodology in cascade reactions is very promising because it provides the combination of the synthetic virtues of the cascade strategy with the ecological benefits and convenience of electrocatalytic procedures. In this research, a new type of the electrocatalytic cascade transformation was found: the electrochemical cyclization of 1,3-dimethyl-5-[[3-hydroxy-6-(hydroxymethyl)-4-oxo-4H-pyran-2-yl](aryl)methyl]pyrimidine-2,4,6(1H,3H,5H)-triones was carried out in alcohols in an undivided cell in the presence of sodium halides with the selective formation of spiro[furo[3,2-b]pyran-2,5′-pyrimidines] in 59-95% yields. This new electrocatalytic process is a selective, facile, and efficient way to create spiro[furo[3,2-b]pyran-2,5′-pyrimidines], which are pharmacologically active heterocyclic systems with different biomedical applications. Spiro[furo[3,2-b]pyran-2,5′-pyrimidines] were found to occupy the binding pocket of aldose reductase and inhibit it. The values of the binding energy and Lead Finder’s Virtual Screening scoring function showed that the formation of protein–ligand complexes was favorable. The synthesized compounds are promising for the inhibition of aldose reductase. This makes them interesting for study in the treatment of diabetes or similar diseases. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Solid-State Electrochemical Energy Storage Based on Soluble Melanin

by

João V. Paulin

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Silvia L. Fernandes

and

Carlos F. O. Graeff

Electrochem 2021, 2(2), 264-273; https://doi.org/10.3390/electrochem2020019 - 25 May 2021

Viewed by 618

Abstract

Biocompatible and biodegradable powering materials are appealing systems for biomedical and electronic devices. Melanin is a natural and multifunctional material with redox capability, which is of great interest in electrochemical energy storage functionalities. In our work, we explored the use of soluble melanin [...] Read more.

Biocompatible and biodegradable powering materials are appealing systems for biomedical and electronic devices. Melanin is a natural and multifunctional material with redox capability, which is of great interest in electrochemical energy storage functionalities. In our work, we explored the use of soluble melanin derivatives as active materials for symmetric solid-state supercapacitors operating in the dark and under illumination. We observed that our devices were photo-pseudocapacitive. Additionally, under illumination, our best device showed a specific capacitance of 57.7 mFg⁻¹ at a scan rate of 0.01 Vs⁻¹, with a decrease of 53% in resistance compared to that in the dark. Our outcome suggests that soluble melanin is a promising material for solid-state powering elements in wearable and environmentally friendly devices. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Development of an Electrochemical Sensor Based on Nanocomposite of Fe₃O₄@SiO₂ and Multiwalled Carbon Nanotubes for Determination of Tetracycline in Real Samples

by

Edna Ferreira Amaral

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Daniela Nunes da Silva

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Maria Cristina Silva

and

Arnaldo César Pereira

Electrochem 2021, 2(2), 251-263; https://doi.org/10.3390/electrochem2020018 - 18 May 2021

Viewed by 579

Abstract

In this work, an electrochemical sensor (GCE/MWCNT/Fe₃O₄@SiO₂) based on a composite of multiwalled carbon nanotubes (MWCNT) and an Fe₃O₄@SiO₂ (MMN) nanocomposite on a glassy carbon electrode (GCE) was developed for the detection [...] Read more.

In this work, an electrochemical sensor (GCE/MWCNT/Fe₃O₄@SiO₂) based on a composite of multiwalled carbon nanotubes (MWCNT) and an Fe₃O₄@SiO₂ (MMN) nanocomposite on a glassy carbon electrode (GCE) was developed for the detection of tetracycline (TC). The composite formed promoted an increased electrochemical signal and the stability of the sensor, combining its individual characteristics such as high electrical conductivity and large surface area. The composite material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Mössbauer spectroscopy, and scanning electron microscope (SEM). The adsorptive stripping differential pulse voltammetry (AdSDPV) promoted better performance for the electrochemical sensor and greater sensitivity for TC detection. Under optimized conditions, the currents increased linearly with TC concentrations from 4.0 to 36 µmol L⁻¹ (0.997) and from 40 to 64 µmol L⁻¹ (0.994) with detection and quantification limits of 1.67 µmol L⁻¹ and 4.0 µmol L⁻¹, respectively. The sensor was applied in the analysis of milk and river water samples, obtaining recovery values ranging from 91–117%. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Electrolytic Reduction of Titanium Dioxide in Molten LiCl–Li₂O

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Electrochem 2021, 2(2), 224-235; https://doi.org/10.3390/electrochem2020016 - 27 Apr 2021

Viewed by 627

Abstract

The electrolytic reduction of TiO₂ in LiCl–Li₂O (1 wt.%) at 650 °C was investigated under a series of cathodic reduction potentials and applied charges to provide a mechanistic understanding of the electrochemical characteristics of the system. The optimal cathodic reduction [...] Read more.

The electrolytic reduction of TiO₂ in LiCl–Li₂O (1 wt.%) at 650 °C was investigated under a series of cathodic reduction potentials and applied charges to provide a mechanistic understanding of the electrochemical characteristics of the system. The optimal cathodic reduction potential was determined as being −0.3 V vs. Li/Li⁺. Li₂TiO₃ and LiTiO₂ were structurally identified as intermediate and partial reduction products of the TiO₂ electrolytic reduction. The reduction of LiTiO₂ was extremely slow and reversible due to its high stability and the detrimental effect of Li₂O accumulation within the solid particles. The most reduced product obtained in this study was LiTiO₂, which was achieved when using 150% of the theoretical charge under the optimal reduction potential. The highest reduction extent obtained in this study was 25%. Based on theoretical DFT modeling, a detailed multistep reduction mechanism and scheme were proposed for TiO₂ electrolytic reduction in LiCl–Li₂O (1 wt.%) at 650 °C. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Electrodeposition of Aluminum in the 1-Ethyl-3-Methylimidazolium Tetrachloroaluminate Ionic Liquid

by

Meng Shi

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Junhua Jiang

and

Haiyan Zhao

Electrochem 2021, 2(2), 185-196; https://doi.org/10.3390/electrochem2020013 - 26 Mar 2021

Viewed by 866

Abstract

The electrodeposition of Al was investigated in an ionic liquid (IL), with 1-ethyl-3-methylimidazolium tetrachloroaluminate ([EMIm]AlCl₄) as the electrolyte with AlCl₃ precursor. The [EMIm]AlCl₄ electrolyte exhibited a wide and stable electrochemical window from 3.2 to 2.3 V on a glassy [...] Read more.

The electrodeposition of Al was investigated in an ionic liquid (IL), with 1-ethyl-3-methylimidazolium tetrachloroaluminate ([EMIm]AlCl₄) as the electrolyte with AlCl₃ precursor. The [EMIm]AlCl₄ electrolyte exhibited a wide and stable electrochemical window from 3.2 to 2.3 V on a glassy carbon electrode when temperature was increased from 30 °C to 110 °C. The addition of AlCl₃ into [EMIm]AlCl₄ generated significant well-developed nucleation growth loops, and new coupled reduction and oxidation peaks in cyclic voltammograms corresponding to the Al deposition and dissolution, respectively. A calculation model was proposed predicting compositions of anions in AlCl₃/[EMIm]AlCl₄ system, and [Al₂Cl₇]⁻ was found to be the active species for Al deposition. In AlCl₃/[EMIm]AlCl₄ (1:5), the reduction rate constants were 1.18 × 10⁻⁵ cm s⁻¹ and 3.37 × 10⁻⁴ cm s⁻¹ at 30 °C and 110 °C, respectively. Scanning electron microscope (SEM), energy dispersive spectroscope (EDS), and X-ray diffraction (XRD) microscope results showed that the metallic Al film had been successfully deposited on glassy carbon electrodes through constant-potential cathodic reductions. The [EMIm]AlCl₄ was a promising electrolyte directly used for Al deposition. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessArticle

Investigation of the Applicability of Helium-Based Cooling System for Li-Ion Batteries

by

Mohammad Alipour

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Aliakbar Hassanpouryouzband

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Riza Kizilel

Electrochem 2021, 2(1), 135-148; https://doi.org/10.3390/electrochem2010011 - 08 Mar 2021

Cited by 1 | Viewed by 783

Abstract

This paper proposes a novel He-based cooling system for the Li-ion batteries (LIBs) used in electric vehicles (EVs) and hybrid electric vehicles (HEVs). The proposed system offers a novel alternative battery thermal management system with promising properties in terms of safety, simplicity, and [...] Read more.

This paper proposes a novel He-based cooling system for the Li-ion batteries (LIBs) used in electric vehicles (EVs) and hybrid electric vehicles (HEVs). The proposed system offers a novel alternative battery thermal management system with promising properties in terms of safety, simplicity, and efficiency. A 3D multilayer coupled electrochemical-thermal model is used to simulate the thermal behavior of the 20 Ah LiFePO₄ (LFP) cells. Based on the results, He gas, compared to air, effectively diminishes the maximum temperature rise and temperature gradient on the cell surface and offers a viable option for the thermal management of Li-ion batteries. For instance, in comparison with air, He gas offers 1.18 and 2.29 °C better cooling at flow rates of 2.5 and 7.5 L/min, respectively. The cooling design is optimized in terms of the battery’s temperature uniformity and the battery’s maximum temperature. In this regard, the effects of various parameters such as inlet diameter, flow direction, and inlet flow rate are investigated. The inlet flow rate has a more evident influence on the cooling efficiency than inlet/outlet diameter and flow direction. The possibility of using helium as a cooling fluid is shown to open new doors in the subject matter of an effective battery thermal management system. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Review

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Open AccessReview

Graphene Quantum Dots-Based Nanocomposites Applied in Electrochemical Sensors: A Recent Survey

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Electrochem 2021, 2(3), 490-519; https://doi.org/10.3390/electrochem2030032 - 06 Sep 2021

Viewed by 167

Abstract

Graphene quantum dots (GQDs) have been widely investigated in recent years due to their outstanding physicochemical properties. Their remarkable characteristics allied to their capability of being easily synthesized and combined with other materials have allowed their use as electrochemical sensing platforms. In this [...] Read more.

Graphene quantum dots (GQDs) have been widely investigated in recent years due to their outstanding physicochemical properties. Their remarkable characteristics allied to their capability of being easily synthesized and combined with other materials have allowed their use as electrochemical sensing platforms. In this work, we survey recent applications of GQDs-based nanocomposites in electrochemical sensors and biosensors. Firstly, the main characteristics and synthesis methods of GQDs are addressed. Next, the strategies generally used to obtain the GQDs nanocomposites are discussed. Emphasis is given on the applications of GQDs combined with distinct 0D, 1D, 2D nanomaterials, metal-organic frameworks (MOFs), molecularly imprinted polymers (MIPs), ionic liquids, as well as other types of materials, in varied electrochemical sensors and biosensors for detecting analytes of environmental, medical, and agricultural interest. We also discuss the current trends and challenges towards real applications of GQDs in electrochemical sensors. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Review on Interface and Interphase Issues in Sulfide Solid-State Electrolytes for All-Solid-State Li-Metal Batteries

by

Young-Woon Byeon

and

Haegyeom Kim

Electrochem 2021, 2(3), 452-471; https://doi.org/10.3390/electrochem2030030 - 02 Aug 2021

Viewed by 680

Abstract

All-solid-state batteries have emerged as promising alternatives to conventional Li-ion batteries owing to their higher energy density and safety, which stem from their use of inorganic solid-state electrolytes instead of flammable organic liquid electrolytes. Among various candidates, sulfide solid-state electrolytes are particularly promising [...] Read more.

All-solid-state batteries have emerged as promising alternatives to conventional Li-ion batteries owing to their higher energy density and safety, which stem from their use of inorganic solid-state electrolytes instead of flammable organic liquid electrolytes. Among various candidates, sulfide solid-state electrolytes are particularly promising for the development of high-energy all-solid-state Li metal batteries because of their high ionic conductivity and deformability. However, a significant challenge remains as their inherent instability in contact with electrodes forms unstable interfaces and interphases, leading to degradation of the battery performance. In this review article, we provide an overview of the key issues for the interfaces and interphases of sulfide solid-state electrolyte systems as well as recent progress in understanding such interface and interphase formation and potential solutions to stabilize them. In addition, we provide perspectives on future research directions in this field. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Crystal Structure and Preparation of Li₇La₃Zr₂O₁₂ (LLZO) Solid-State Electrolyte and Doping Impacts on the Conductivity: An Overview

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Electrochem 2021, 2(3), 390-414; https://doi.org/10.3390/electrochem2030026 - 19 Jul 2021

Viewed by 574

Abstract

As an essential part of solid-state lithium-ion batteries, solid electrolytes are receiving increasing interest. Among all solid electrolytes, garnet-type Li₇La₃Zr₂O₁₂ (LLZO) has proven to be one of the most promising electrolytes because of its high ionic [...] Read more.

As an essential part of solid-state lithium-ion batteries, solid electrolytes are receiving increasing interest. Among all solid electrolytes, garnet-type Li₇La₃Zr₂O₁₂ (LLZO) has proven to be one of the most promising electrolytes because of its high ionic conductivity at room temperature, low activation energy, good chemical and electrochemical stability, and wide potential window. Since the first report of LLZO, extensive research has been done in both experimental investigations and theoretical simulations aiming to improve its performance and make LLZO a feasible solid electrolyte. These include developing different methods for the synthesis of LLZO, using different crucibles and different sintering temperatures to stabilize the crystal structure, and adopting different methods of cation doping to achieve more stable LLZO with a higher ionic conductivity and lower activation energy. It also includes intensive efforts made to reveal the mechanism of Li ion movement and understand its determination of the ionic conductivity of the material through molecular dynamic simulations. Nonetheless, more insightful study is expected in order to obtain LLZO with a higher ionic conductivity at room temperature and further improve chemical and electrochemical stability, while optimal multiple doping is thought to be a feasible and promising route. This review summarizes recent progress in the investigations of crystal structure and preparation of LLZO, and the impacts of doping on the lithium ionic conductivity of LLZO. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessReview

Developments of the Electroactive Materials for Non-Enzymatic Glucose Sensing and Their Mechanisms

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Electrochem 2021, 2(2), 347-389; https://doi.org/10.3390/electrochem2020025 - 21 Jun 2021

Viewed by 510

Abstract

A comprehensive review of the electroactive materials for non-enzymatic glucose sensing and sensing devices has been performed in this work. A general introduction for glucose sensing, a facile electrochemical technique for glucose detection, and explanations of fundamental mechanisms for the electro-oxidation of glucose [...] Read more.

A comprehensive review of the electroactive materials for non-enzymatic glucose sensing and sensing devices has been performed in this work. A general introduction for glucose sensing, a facile electrochemical technique for glucose detection, and explanations of fundamental mechanisms for the electro-oxidation of glucose via the electrochemical technique are conducted. The glucose sensing materials are classified into five major systems: (1) mono-metallic materials, (2) bi-metallic materials, (3) metallic-oxide compounds, (4) metallic-hydroxide materials, and (5) metal-metal derivatives. The performances of various systems within this decade have been compared and explained in terms of sensitivity, linear regime, the limit of detection (LOD), and detection potentials. Some promising materials and practicable methodologies for the further developments of glucose sensors have been proposed. Firstly, the atomic deposition of alloys is expected to enhance the selectivity, which is considered to be lacking in non-enzymatic glucose sensing. Secondly, by using the modification of the hydrophilicity of the metallic-oxides, a promoted current response from the electro-oxidation of glucose is expected. Lastly, by taking the advantage of the redistribution phenomenon of the oxide particles, the usage of the noble metals is foreseen to be reduced. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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A Short Review on Electrochemical Sensing of Commercial Dyes in Real Samples Using Carbon Paste Electrodes

by

Isha Soni

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Pankaj Kumar

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Shruti Sharma

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Gururaj Kudur Jayaprakash

Electrochem 2021, 2(2), 274-294; https://doi.org/10.3390/electrochem2020020 - 25 May 2021

Viewed by 668

Abstract

Synthetic dyes are commonly used in food products like soft drinks, vegetable sauces, jellies, etc. Most artificial dyes can cause cancer, therefore it is very important to develop sensors to detect them in food samples. Voltammetric methods with carbon paste electrodes (CPEs) are [...] Read more.

Synthetic dyes are commonly used in food products like soft drinks, vegetable sauces, jellies, etc. Most artificial dyes can cause cancer, therefore it is very important to develop sensors to detect them in food samples. Voltammetric methods with carbon paste electrodes (CPEs) are promising for this purpose. However, modification of CPEs is necessary to detect the commercial dyes in food samples in the presence of interferents. In the current review, we have discussed the different previous research in which detection of dyes is performed in real samples with good detection limits. The current review will be helpful for readers who are interested in developing low-cost electrodes for the effective determination of dyes in commercial products like soft drinks and vegetable sauces. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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Open AccessReview

Wearable Nanogenerators: Working Principle and Self-Powered Biosensors Applications

by

Helinando Pequeno de Oliveira

Electrochem 2021, 2(1), 118-134; https://doi.org/10.3390/electrochem2010010 - 28 Feb 2021

Viewed by 921

Abstract

Wearable self-powered sensors represent a theme of interest in the literature due to the progress in the Internet of Things and implantable devices. The integration of different materials to harvest energy from body movement or the environment to power up sensors or act [...] Read more.

Wearable self-powered sensors represent a theme of interest in the literature due to the progress in the Internet of Things and implantable devices. The integration of different materials to harvest energy from body movement or the environment to power up sensors or act as an active component of the detection of analytes is a frontier to be explored. This review describes the most relevant studies of the integration of nanogenerators in wearables based on the interaction of piezoelectric and triboelectric devices into more efficient and low-cost harvesting systems to power up batteries or to use the generated power to identify multiple analytes in self-powered sensors and biosensors. Full article

(This article belongs to the Special Issue Exclusive Papers Collection of Editorial Board Members of Electrochem 2021)

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