| 1. |
- Ansarian, Zahra, et al.
(författare)
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Titanium germanium carbide MAX phase electrocatalysts for supercapacitors and alkaline water electrolysis processes
- 2023
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Ingår i: Materials Today Chemistry. - : Elsevier BV. - 2468-5194. ; 33
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Tidskriftsartikel (refereegranskat)abstract
- Developing electrochemically active, stable, and low-cost electrocatalysts for electrochemical devices is a significant breakthrough. Accordingly, MAX phases, emerging three-dimensional materials, are considered outstanding candidates due to their excellent electrocatalytic and electrochemical properties. Herein, the titanium germanium carbide (Ti3GeC2) MAX phase with a layered structure manufactured through reactive sintering was regarded as the electrocatalyst. In the current work, the electrocatalytic activity of the Ti3GeC2 was investigated for electrochemical devices. It was observed that adding activated carbon to the Ti3GeC2 enhances the conductivity and active area, leading to an excellent specific capacitance (349 Fg-1) for supercapacitors. Also, the capacitance of Ti3GeC2 was increased by increasing the number of cyclic voltammetry cycles. In another application, Ti3GeC2 showed substantial activity for hydrogen and oxygen evolution reactions in alkaline media. As a result, the alkaline water electrolysis system using Ti3GeC2 showed the highest current density of 10 mA cm−2 at 1.36 V and outstanding stability over 400 cycles.
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| 2. |
- Zakeri, Fatemeh, et al.
(författare)
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Al-Ce co-doped BaTiO3 nanofibers as a high-performance bifunctional electrochemical supercapacitor and water-splitting electrocatalyst
- 2024
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Supercapacitors and water splitting cells have recently played a key role in offering green energy through converting renewable sources into electricity. Perovskite-type electrocatalysts such as BaTiO3, have been well-known for their ability to efficiently split water and serve as supercapacitors due to their high electrocatalytic activity. In this study, BaTiO3, Al-doped BaTiO3, Ce-doped BaTiO3, and Al-Ce co-doped BaTiO3 nanofibers were fabricated via a two-step hydrothermal method, which were then characterized and compared for their electrocatalytic performance. Based on the obtained results, Al-Ce co-doped BaTiO3 electrode exhibited a high capacitance of 224.18 Fg−1 at a scan rate of 10 mVs−1, high durability during over the 1000 CV cycles and 2000 charge–discharge cycles, proving effective energy storage properties. Additionally, the onset potentials for OER and HER processes were 11 and − 174 mV vs. RHE, respectively, demonstrating the high activity of the Al-Ce co-doped BaTiO3 electrode. Moreover, in overall water splitting, the amount of the overpotential was 0.820 mV at 10 mAcm−2, which confirmed the excellent efficiency of the electrode. Hence, the remarkable electrocatalytic performance of the Al-Ce co-doped BaTiO3 electrode make it a promising candidate for renewable energy technologies owing to its high conductivity and fast charge transfer.
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| 3. |
- Abdelaziz, Omar Y., et al.
(författare)
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Recent strides toward transforming lignin into plastics and aqueous electrolytes for flow batteries
- 2024
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Ingår i: iScience. - : Elsevier Inc.. - 2589-0042. ; 27:4
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Forskningsöversikt (refereegranskat)abstract
- Lignin is an abundant polyaromatic polymer with a wide range of potential future uses. However, the conversion of lignin into valuable products comes at a cost, and medium- to high-value applications are thus appropriate. Two examples of these are polymers (e.g., as fibers, plasticizers, or additives) and flow batteries (e.g., as redox species). Both of these areas would benefit from lignin-derived molecules with potentially low molecular weight and high (electro)chemical functionality. A promising route to obtain these molecules is oxidative lignin depolymerization, as it enables the formation of targeted compounds with multiple functionalities. An application with high potential in the production of plastics is the synthesis of new sustainable polymers. Employing organic molecules, such as quinones and heterocycles, would constitute an important step toward the sustainability of aqueous flow batteries, and lignin and its derivatives are emerging as redox species, mainly due to their low cost and renewability.
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| 4. |
- Khataee, Amirreza, et al.
(författare)
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Anion exchange membrane water electrolysis using Aemion membranes and nickel electrodes
- 2022
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Ingår i: Journal of Materials Chemistry A. - 2050-7488. ; 10:30, s. 16061-16070
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Tidskriftsartikel (refereegranskat)abstract
- Anion exchange membrane water electrolysis (AEMWE) is a potentially low-cost and sustainable technology for hydrogen production that combines the advantages of proton exchange membrane water electrolysis and traditional alkaline water electrolysis systems. Despite considerable research efforts in recent years, the medium-term (100 h) stability of AemionTM membranes needs further investigation. This work explores the chemical and electrochemical durability (>100 h) of AemionTM anion exchange membranes in a flow cell using nickel felt as electrode material on the anode and cathode sides. Remixing the electrolytes between the AEMWE galvanostatic tests was very important to enhance electrolytes refreshment and the voltage stability of the system. The membranes were analyzed by NMR spectroscopy after the AEMWE tests, and the results showed no sign of severe chemical degradation. In a separate experiment, the chemical stability and mechanical integrity of the membranes were studied by soaking them in a strongly alkaline electrolyte for a month (>700 h) at 90 °C, followed by NMR analysis. A certain extent of ionic loss was observed due to chemical degradation and the membranes disintegrated into small pieces.
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| 5. |
- khataee, Amirreza, et al.
(författare)
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Anion exchange membrane water electrolysis using Aemion™ membranes and nickel electrodes
- 2022
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 10:30, s. 16061-16070
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Tidskriftsartikel (refereegranskat)abstract
- Anion exchange membrane water electrolysis (AEMWE) is a potentially low-cost and sustainable technology for hydrogen production that combines the advantages of proton exchange membrane and traditional alkaline water electrolysis systems.
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| 6. |
- Khataee, Amirreza, et al.
(författare)
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Asymmetric cycling of vanadium redox flow batteries with a poly(arylene piperidinium)-based anion exchange membrane
- 2021
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 483
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Tidskriftsartikel (refereegranskat)abstract
- The potential application of a 50 μm thick anion exchange membrane prepared based on poly(terphenyl piperidinium-co-trifluoroacetophenone) (PTPT) is investigated for vanadium redox flow batteries (VRFBs). The PTPT exhibits a considerably lower vanadium permeation than Nafion 212. Therefore, the self-discharge duration of the VRFB based on PTPT is much longer than the VRFB based on Nafion 212. Besides, PTPT shows oxidative stability almost as good as Nafion 212 during immersion in an ex-situ immersion test for more than 400 h. Comparing the VRFB performance when symmetric and asymmetric electrolyte volumes are used yields interesting results. The results show that asymmetric cycling is more effective and efficient for the VRFB assembled with PTPT than Nafion 212 as the capacity fade of 0.03% cycle−1, and the highest coulombic efficiency of 98.8% is attained. Furthermore, the color change of the membrane during cycling can be reversed using a straightforward post-treatment method.
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| 7. |
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| 8. |
- Khataee, Amirreza, et al.
(författare)
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Poly(arylene alkylene)s functionalized with perfluorosulfonic acid groups as proton exchange membranes for vanadium redox flow batteries
- 2023
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Ingår i: Journal of Membrane Science. - : Elsevier BV. - 0376-7388 .- 1873-3123. ; 671
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Tidskriftsartikel (refereegranskat)abstract
- With the aim to develop vanadium redox flow battery (VRFB) membranes beyond state of the art, we have in the present work functionalized poly(p-terphenylene)s with highly acidic perfluorosulfonic groups and investigated their performance as proton exchange membranes (PEMs). Consequently, two poly(p-terphenylene alkylene)s tethered with perfluoroalkylsulfonic acid and perfluorophenylsulfonic acid, respectively, were synthesized through superacid-mediated polyhydroxyalkylations and cast into PEMs. Compared with Nafion 212, the PEM carrying perfluorophenylsulfonic acid groups (PTPF-Phenyl-SA) was found to exhibit higher ionic conductivity and eight times lower vanadium (IV) permeation rate. The latter explains the longer self-discharge duration of the VRFB based on the PTPF-Phenyl-SA. In addition, the VRFB assembled with the PTPF-Phenyl-SA PEM exhibited a high average coulombic efficiency of 99.6% for over 100 cycles with a capacity fade of 0.24% per cycle, which was 50% lower than when Nafion 212 was used. More importantly, excellent capacity retention was achieved through electrochemical rate performance experiments at different current densities.
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| 9. |
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| 10. |
- Lallo, Elias, et al.
(författare)
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Vanadium Redox Flow Battery Using Aemion((TM)) Anion Exchange Membranes
- 2022
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Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- The vanadium redox flow battery (VRFB) is a promising and commercially available technology that poses advantageous features for stationary energy storage. A key component of the VRFB in terms of cost and system efficiency is the membrane. In recent years, anion exchange membranes (AEMs) have gained interest in VRFB research as they in general exhibit lower vanadium crossover due to a more substantial Donnan exclusion effect. In this study, a low-resistance flow cell was developed and the electrochemical performance of Aemion (TM) anion exchange membranes AF1-HNN5-50-X, AF1-HNN8-50-X and AF1-ENN8-50-X were compared against commonly used cation exchange membranes, Nafion(R) 211 and 212. The VRFB using AF1-ENN8-50-X exhibited superior performance versus Nafion(R) 212 regarding cycling efficiency and rate performance. However, relatively high and comparable capacity losses were observed using both membranes. NMR analysis showed no sign of chemical degradation for AF1-ENN8-50-X by immersion in VO2+ solution for 800 h. Although Aemion (TM) AEMs showed good chemical and electrochemical performance, considerable electrolyte crossover was observed due to high water uptake.
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| 11. |
- Ramirez, Erlantz Villar, et al.
(författare)
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Electrochemical and Kinetic Analysis of Manganese Electrolytes for Redox Flow Batteries
- 2024
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 171:8
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Tidskriftsartikel (refereegranskat)abstract
- The hybrid hydrogen-manganese redox flow battery (H2-Mn RFB) is a promising and sustainable electrochemical system for long-duration energy storage. One strong reason is the excellent features of manganese, such as low cost, abundance, environmental friendliness, and relatively high standard potential (+1.51 V). Nevertheless, the electrochemical and kinetic parameters of manganese electrolytes have not been studied in detail for flow batteries. In the present work, the kinetics of the Mn2+/Mn3+ redox species in an electrolyte composed of 1M TiOSO4 and 1M MnSO4 in 3M H2SO4 were studied on carbon paper electrodes. The kinetic analysis of manganese redox species (Mn2+/Mn3+) in the presence of TiO2+ was performed using cyclic voltammetry and electrochemical impedance spectroscopy techniques within the H2-Mn RFB set-up. The results were compared to reference redox species vanadium (VO2+/VO2 +) within H2-V RFB system. The results showed that the heterogeneous electron transfer rate constant (8.6 x 10-7 cm s-1) of manganese is comparable to that of vanadium (4.8 x 10-6 cm s-1), with less than an order of magnitude difference between them. Cyclic voltammetry (CV) in flow battery setup was used to calculate kinetics data.MnSO4 and TiOSO4 with a 1:1 molar ratio in 3 M H2SO4 was optimal composition.Kinetic data of manganese was found pretty comparable to benchmark vanadium.The electrochemical impedance spectroscopy technique confirmed CV data.Hydrogen-Manganese flow battery showed 97% capacity retention for 40 cycles.
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| 12. |
- Rossini, Matteo, et al.
(författare)
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High performance water electrolysis using a poly(fluorene phenylpropylammonium) anion-exchange membrane with 2 M aqueous KOH
- 2024
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Ingår i: Journal of Materials Chemistry A. - 2050-7488. ; 12:21, s. 12826-12834
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Tidskriftsartikel (refereegranskat)abstract
- Anion exchange membrane water electrolysis (AEMWE) has a great potential to be established as a high-performance and low-capital cost technology for hydrogen production. High current densities can be achieved with non-platinum group metal (non-PGM) catalyst. However, the harsh operation conditions require stable cell components. Here, we report on the use of a highly stable and ion conductive poly(fluorene alkylene) membrane (PdF-TMA) tethered with trimethylammonium cations via phenylpropyl side chains for AEMWEs operating with 2 M aqueous KOH. The ether-free PdF-TMA polymer is efficiently prepared by polyhydroxyalkylation to reach a molecular weight of 236 kDa, a high thermal stability, and an ion-exchange capacity of 2.14 mequiv. g-1 (OH− form). Using commercial electrodes of NiFe2O4 (anode) and Raney Nickel (cathode) and PdF-TMA as AEM, the output current reached 1 A cm-2 at below 1.9 V at 60 °C. Also, PdF-TMA outperformed AEMIONTM membrane resistance by almost 30% and, after 100 h at 0.5 A cm-2, did not reveal any loss of conductivity, contrary to AEMIONTM. Furthermore, both membranes were analysed by 1H NMR spectroscopy after AEMWE tests and the PdF-TMA proved very stable even at 80 °C.
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| 13. |
- Rossini, Matteo, et al.
(författare)
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Rational design of membrane electrode assembly for anion exchange membrane water electrolysis systems
- 2024
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 614
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Tidskriftsartikel (refereegranskat)abstract
- Anion exchange membrane water electrolysis (AEMWE) is a promising and potentially low-cost technology for producing green hydrogen, but a novel manufacturing technique with rational design of the electrodes is essential to improve the performance and stability. In this work, we investigate the effect of electrode structure on activity and the stability of AEMWEs by fabricating membrane electrode assemblies (MEAs). For the first time, the decal transfer method with platinum-group-metal-free (PGM-free) catalyst was successfully used in AEMWEs. With this method, deposition of a compact catalyst layer (CL) on the membrane was achieved without damaging neither the CL nor the membrane. The MEAs were designed for AEMWE using 1 M KOH as the electrolyte and the ionomer content was optimized for both cathode and anode. In the anode, a low ionomer loading improved activity and ionic conductivity, however, a higher ionomer content was beneficial for the cathode. Furthermore, the type of ionomer on the anode side has shown to be the major reason of loss of performance over time. An ionomer with low (1.4–1.7 meq g−1) Ion Exchange Capacity (IEC) and Nafion™ ionomer greatly improved the stability.
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| 14. |
- Salmeron-Sanchez, Ivan, et al.
(författare)
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Zwitterionic poly(terphenylene piperidinium) membranes for vanadium redox flow batteries
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 474
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Tidskriftsartikel (refereegranskat)abstract
- Over recent years, non-fluorinated ion exchange membranes based on poly(terphenylene) backbones carrying different functional groups have shown potential application for vanadium redox flow batteries (VRFBs). Generally, the ion exchange membrane in VRFBs is a critical component in terms of the output power, long-term stability and cost. Yet, the shortcomings of commercial membranes (e.g., Nafion) have become a substantial barrier to further commercializing VRFBs. After successfully fabricating and testing poly(terphenylene)-based membranes carrying piperidinium and sulfonic acid groups, respectively, for VRFBs, we have in the present work combined both these ionic groups in a single zwitterionic membrane. A series of poly(terphenylene)-based membranes containing zwitterionic (sulfoalkylated piperidinium) and cationic (piperidinium) groups in different ratios (40–60%) were synthesized and investigated. The VRFB using the zwitterionic membranes showed competitive performance compared to Nafion 212 regarding ionic conductivity, capacity retention, and chemical stability. In addition, it was shown that the VRFB performance was improved by increasing the content of zwitterionic groups within the membrane. A self-discharge time of more than 800 h and 78.7% average capacity retention for 500 VRFB cycles were achieved using a membrane with an optimized ratio (60% zwitterionic and 40% piperidinium groups). Furthermore, the chemical stability was promising, as there was no change in the chemical structure after 500 cycles. Our results represent a critical step for developing novel and competitive ion exchange membranes as an excellent alternative to the Nafion benchmark.
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| 15. |
- Teenakul, Kavin, et al.
(författare)
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Treatment of carbon electrodes with Ti3C2Tx MXene coating and thermal method for vanadium redox flow batteries : a comparative study
- 2024
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 14:18, s. 12807-12816
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Tidskriftsartikel (refereegranskat)abstract
- One of the significant challenges of vanadium redox flow batteries is connected to the negative electrode where the main reaction of V(II)/V(III) and the side reaction of hydrogen evolution compete. To address this issue, we used titanium carbide (Ti3C2Tx) MXene coating via drop-casting to introduce oxygen functional groups and metals on the carbon electrode surface. Characterization through scanning electron microscopy and X-ray photoelectron spectroscopy confirmed the even distribution of Ti3C2Tx MXene on the electrodes and the presence of titanium and termination groups (-O, -Cl, and -F). The cyclic voltammetry analysis of MXene-coated electrodes showed more sharp electrochemical peaks for the V(II)/V(III) reaction than thermal-treated electrodes, even at relatively high scan rates. Notably, a relatively high reaction rate of 5.61 x 10(-4) cm s(-1) was achieved for the V(II)/V(III) reaction on MXene-coated electrodes, which shows the competitiveness of the method compared to thermal treatment (4.17 x 10(-4) cm s(-1)). The flow battery tests, at a current density of 130 mA cm(-2), using MXene-coated electrodes showed pretty stable discharge capacity for over 100 cycles. In addition, the voltage and energy efficiency were significantly higher than those of the system using untreated electrodes. Overall, this work highlights the potential application of MXene coating in carbon electrode treatment for vanadium redox flow batteries due to remarkable electrocatalytic activity and battery performance, providing a competitive method for thermal treatment.
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