Journal of Solid State Electrochemistry

Käärik, Maike; Arulepp, Mati; Kozlova, Jekaterina; Aruväli, Jaan; Mäeorg, Uno; Kikas, Arvo; Kisand, Vambola; Tamm, Aile; Leis, Jaan

doi: 10.1007/s10008-022-05253-4pmid: N/A

The present study considers TiC-derived carbon (CDC) and its partially oxidized derivative (ox-red-CDC) as potential electrode materials for pH-neutral aqueous electrolytes. The CDC was converted to ox-red-CDC by a modified Hummers’ method involving back-reduction with hydrogen at 800 °C. Oxidation degraded the graphitic CDC structures, as shown by X-ray diffraction analysis, while scanning electron microscopy confirmed the exfoliation of graphene layers on the oxidized carbon surface. The changes in the surface chemistry of the carbon materials were studied by infrared, X-ray photoelectron, and energy-dispersive X-ray spectroscopy. The gas adsorption analysis showed a slight decrease in the volume of the subnanometer-sized pores during oxidation/reduction of CDC. To elucidate the relationships between the structure and electrochemical properties of carbon materials, cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy measurements were performed in 1 M Na2SO4 using 2- and 3-electrode test cells. The highest capacitance of 163 F g−1 was demonstrated by pristine TiC-derived CDC in a symmetric 2-electrode cell. The asymmetric cell, which contained ox-red-CDC as an anode and pristine CDC as a cathode, had a slightly lower capacitance but an excellent cycling lifetime (specific capacitance increased by 7% after 5000 cycles). Temporary repolarization of 2-electrode cells during cycling improved both capacitance and power characteristics.Graphical abstract[graphic not available: see fulltext]

Liu, Leilei; Su, Guobiao; Cheng, Xu; Han, Han; Qiang, Wenjiang; Huang, Bingxin

doi: 10.1007/s10008-022-05249-0pmid: N/A

Li-rich Mn-based xLi2MnO3∙(1-x)LiMO2 (M = Ni, Co, Mn) cathode materials have attracted extensive attention because of their specific discharge capacity (250–300 mAh g−1). However, their applications are significantly limited due to disadvantages, such as the low efficiency, the fast capacity attenuation, and the poor rate capability. Therefore, it is important to investigate the mechanisms controlling the electrochemical properties and improve the performances. As a solid solution, xLi2MnO3∙(1-x)LiMO2 is composed of the hexagonal phase LiMO2 and the monoclinic phase Li2MnO3. In this study, the influence of elements Ni and Li on the electrochemical properties of xLi2MnO3∙(1-x)LiMO2 is systematically studied. It is found that the decrease of Li content can lead to the increase of LiMO2 in LixCo0.13Ni0.13Mn0.54O2 system. LiMO2 might span the whole grain with the Li deficiency, thus contributing to the rapid conduction of Li ions. Meanwhile, Li2MnO3 can benefit the structural stability. The synergistic effect of the two components results in the excellent electrochemical performances.

Fahimi, Zohre; Ghasemi, Maryam; Alavijeh, Faezeh Karimi; Moradlou, Omran

doi: 10.1007/s10008-022-05260-5pmid: N/A

In this work, the asymmetric supercapacitor (ASC) devices with three different electrolytes including aqueous, organic, and gel polymer electrolytes have been fabricated to investigate and compare the potential window and the capacitive efficiency of the fabricated devices. The aqueous electrolyte includes potassium hydroxide (KOH, 6.0 M), the organic electrolyte is a solution of lithium hexafluorophosphate (LiPF6, 1.0 M in ethylene carbonate/dimethyl carbonate (EC/DMC)), and the gel polymer electrolyte includes porous poly(acrylonitrile-polyhedral oligomeric silsesquioxane) membrane (P(A-POS)) moistened in 1.0 M solution of LiPF6 in EC/DMC. The positive electrode was a cobalt oxide-based electrode, i.e., Co3O4 nanoribbons (NRCo3O4), and the negative electrode was the activated carbon (AC). The specific capacitance of the supercapacitor with aqueous electrolyte (A-ASC) at the current density of 2 A g−1 is 88.0 F g−1, which has a higher specific capacitance than that of the supercapacitor with organic electrolyte (O-ASC) and the supercapacitor with gel polymer electrolyte (G-ASC). The gel polymer electrolyte for NRCo3O4//AC device shows a wide potential window of 4 V and low charge transfer resistance of 11 Ω. The specific capacitance of NRCo3O4//AC device with gel polymer electrolyte was 54.34 F g−1 at 2 A g−1, which is higher than the specific capacitance of O-ASC.

Abid, Abdul Ghafoor; Manzoor, Sumaira; Ahmad, Zahoor; Hussain, Dilshad; Mersal, Gaber A. M.; El Azab, Islam H.; Elnaggar, Ashraf Y.; El-Nasser, Karam S.; Taha, T. A.; Ashiq, Muhammad Naeem

doi: 10.1007/s10008-022-05232-9pmid:

Madhusudanan, Sreejith P.; Balamoorthy, Elamathy; M., Suresh Kumar; Manivasagam, Thirugnasambandam G.; Batabyal, Sudip K.

doi: 10.1007/s10008-022-05243-6pmid: N/A

Cu2Fe1-xBaxSnS4 (CFBTS) thin films have been fabricated by the low-cost successive ionic layer and adsorption reaction (SILAR) method. The bandgap energies of CFBTS thin films are observed to be tuned from ~ 1.67 to ~ 1.94 eV in a linear manner with increasing Ba content (0 ≤ × ≤ 1). The crystal structure of CFBTS thin films are affected by the change in the Fe/Ba ratio. The structural transition from stannite to trigonal is found with the increased barium content in CFBTS from X-ray diffraction and Raman spectroscopy analysis. Sulfurized CBTS thin film exhibited pure trigonal phase without impurity peaks. Partial replacement of Fe with Ba in CFBTS alters the electronic structure of bulk CFBTS thin films, which affects charge separation and causes a change in band alignment. Finally, photo electrochemical studies were carried out for the as synthesised and the sulfurized samples.

Broncová, Gabriela; Slaninová, Tereza; Trchová, Miroslava

doi: 10.1007/s10008-022-05245-4pmid: N/A

The characterization of electrochemically visualized latent fingerprints on steel surfaces is demonstrated. Optimization of electrochemical conditions of deposited poly(neutral red) (PNR) films on stainless steel substrates, as well as cyclic voltammetry, electrochemical impedance spectroscopy, and ATR FTIR spectroscopy of PNR-modified substrates, was performed. The parameters of the visualization method (supporting electrolyte, monomer concentration, potential range, number of cycles) were gradually changed until the fingerprint was sufficiently visible. The repeatability of measurements under these conditions was especially important, thanks to which many visible fingerprints on steel substrates were successfully obtained. The electrochemical characterization consisted in comparing the redox properties of the metal surfaces themselves before and after the application of the fingerprints or the polymer film PNR. Experimental findings have shown that the use of latent fingerprint visualization is a simple, fast, efficient, and inexpensive method applicable to forensic evidence.Graphical abstract[graphic not available: see fulltext]

Jiang, Demin; Zhu, Chenyi; He, Yuan; Xing, ChengCheng; Xie, Kun; Xu, Yan; Wang, Yuqiao

doi: 10.1007/s10008-022-05255-2pmid: N/A

Anodes play an important role in the extracellular electron transfer (EET) process in microbial fuel cells (MFCs). Herein, polyaniline modified multilayer MXene (PANI-MXene) on carbon cloth was used as an anode to improve the EET efficiency. The PANI-MXene was formed by the electrostatic interaction between the negatively charged groups of MXene and the positively charged protonated amino groups of PANI to enhance the bacterial adhesion and biofilm formation. The MFCs obtained a high maximum power density (737.3 mW·m-2) with the efficient EET process. This work provides a meaningful way to decorate anodes using binder-free modifiers for MFCs.

Ding, Congming; Yuan, Meini; Cao, Xiaochen; Zheng, Lirong; Wang, Kai

doi: 10.1007/s10008-022-05265-0pmid: N/A

In order to meet the growing energy demand, it is of great significance to develop high-performance electrochemical energy storage materials. In this paper, mesoporous Co-Fe nanowires binary hydroxide electrode materials were synthesized by a simple and effective hydrothermal method. Co-Fe binary hydroxide electrode materials are composed of a large number of nanowires with specific surface area of 7.34 m2 g−1 and the average pore size of 12.78 nm. The discharge-specific capacity of the electrode materials is 130.85 mA h g−1 at the current density of 1 A g−1. After charging and discharging at a current density of 5 A g−1 for 1000 time, the discharge-specific capacity retention rate of Co-Fe binary hydroxide electrode materials is 56.5%, and the Coulombic efficiency is almost 100%. Co-Fe binary hydroxide electrode materials show excellent electrochemical performance, indicating that doping with elements with similar chemical properties and multivalent states can effectively improve the electrochemical performance of electrode materials. This idea of doping with elements with similar chemical properties and multivalent states has a certain reference value for improving the performance of electrode materials.

Chetibi, Loubna; Bounab, Mohamed Oussama; Benmkideche, Aymen; Hamana, Djamel; Achour, Slimane

doi: 10.1007/s10008-022-05241-8pmid: N/A

High energy consumption leads to the development of various energy types. As a result, the storage of these different types of energy becomes a key issue. Supercapacitors, as one important energy storage device, have gained much attention especially on electrode materials. The aim of this work is the realization of a flexible supercapacitor using graphene-doped metal oxides graphene/polypyrrole (GP/PPY) nanocomposites as electrodes. Exfoliation and in situ polymerisation are used for graphene and polypyrrole preparation. Metal oxide nanoparticles (Fe2O3 and NiO) are synthesised via green synthesis technique that based on olive leaves’ extract. Gel polymer (polyvinyl alcohol (PVA)—potassium hydroxide (KOH)—hydroquinone (HQ)) is used as an electrolyte and separator. The structural and morphological properties of these components are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscopy (SEM). Electrochemical tests are used to study the effect of the nanooxide particles and the different components of the electrolyte and the separator on the supercapacitor behavior. These tests show a stable supercapacitor for more than 50,000 cycles and different values of the specific capacity are obtained as a function of the combination between metal oxide nanoparticles (Fe2O3 and NiO) and separators (PVA, KOH, HQ and GP/PPY).

Yuan, Dong; Su, Mingyin; Liu, Qibin

doi: 10.1007/s10008-022-05262-3pmid: N/A

The Jahn–Teller effect and severe side reactions with liquid electrolyte have been considered as the main obstacles to the further application of LiMn2O4 electrodes. Herein, Ag nanoparticles (AgNPs) were successfully coated on the surface of LiMn2O4 particles via chemical deposition and pyrolysis methods. The properties, microstructures, and morphologies of LiMn2O4 electrodes were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrometer, and electrochemical performance tests. The results indicated that the LiMn2O4 coated with AgNPs delivered excellent cycling stability and high-rate capability. Especially when the mass fraction of AgNPs-coating was 8 wt%, the specific discharge capacity of the LMO-8 sample was 127.5 mAh g−1 at 0.2C rate; the capacity retention rates over 500 and 100 cycles at 0.5 and 1C rate were 90.2% and 95.4%, respectively; and the specific capacity could reach 101.3 mAh g−1 even at 5C rate. The enhanced electrochemical performance of AgNPs-coated LiMn2O4 can be ascribed to the stabilized surface, high electronic conductivity, and superior kinetic properties. This work demonstrates AgNPs are a kind of coating material suitable for surface modification of LiMn2O4 cathode, and can also be used in the preparation of other types of electrode materials.