15 results found
Lindberg S, Cavallo C, Calcagno G, et al., 2020, Electrochemical Behaviour of Nb-Doped Anatase TiO2 Microbeads in an Ionic Liquid Electrolyte, BATTERIES & SUPERCAPS
Navarro-Suarez AM, Johansson P, 2020, Perspective-Semi-Solid Electrolytes Based on Deep Eutectic Solvents: Opportunities and Future Directions, JOURNAL OF THE ELECTROCHEMICAL SOCIETY, Vol: 167, ISSN: 0013-4651
Navarro-Suarez AM, Johansson P, 2019, A Silatrane:Molecule-Based Crystal Composite Solid-State Electrolyte for All-Solid-State Lithium Batteries, BATTERIES & SUPERCAPS, Vol: 2, Pages: 956-962
Hosseini-Bab-Anari E, Navarro-Suárez AM, Moth-Poulsen K, et al., 2019, Ionic liquid based battery electrolytes using lithium and sodium pseudo-delocalized pyridinium anion salts., Physical Chemistry Chemical Physics, Vol: 21, Pages: 18393-18399, ISSN: 1463-9076
The electrolyte salt plays an important role for the overall performance and safety of lithium- and sodium-ion batteries (LIBs and SIBs, respectively). Here, two new lithium and sodium pseudo-delocalized pyridinium anion based salts were used to prepare ionic liquid (IL) based electrolytes. The Li and Na salts of the 1-methylpyridinum 2,6-dicarboxylate anion (MM26py) were synthesized and dissolved in an IL matrix (Pyr14TFSI) - hence creating mixed anion electrolytes. The obtained electrolytes are stable up to 150 and 200 °C and show ion conductivities of 2.8 and 3.2 mS cm-1 at room temperature, for the LIB and SIB electrolytes, respectively. A competitive effect between the MM26py and the TFSI anions to coordinate the alkali metal cations is observed. Finally, the electrochemical stability windows of 2.3 and 2.5 V, respectively, confirm that these electrolytes can be used practically in medium-voltage LIBs and SIBs.
Navarro-Suarez AM, Saurel D, Sanchez-Fontecoba P, et al., 2018, Temperature effect on the synthesis of lignin-derived carbons for electrochemical energy storage applications, Journal of Power Sources, Vol: 397, Pages: 296-306, ISSN: 0378-7753
Herein, we present a detailed study by N2 sorption and Small Angle X-ray Scattering (SAXS) of the carbonization and KOH activation of lignin for its application as active material for electrochemical energy storage. It has been observed that i) the carbonization of lignin above 700 °C leads to a hard carbon with a large amount of bulk (buried) fine structure microporosity and a good performance as Na-ion negative electrode, ii) when KOH activation is done after complete carbonization it is mainly increasing the accessibility of the initial bulk microporosity, leading to a carbon with good performance as symmetric supercapacitor in aqueous electrolyte and iii) when carbonization and KOH activation are done simultaneously, a distinct pore structure is generated with a large amount of mesopores, suitable for symmetric supercapacitor in organic electrolyte. By combining SAXS, which is sensitive to bulk as well as surface porosity, and N2 sorption which probes surface porosity, it has been possible to follow the intricate mechanism of microporosity development. Finally, it is believed that these results can be extrapolated to various biomass based precursors.
Navarro-Suárez AM, Maleski K, Makaryan T, et al., 2018, 2D Titanium Carbide/Reduced Graphene Oxide Heterostructures for Supercapacitor Applications, Batteries & Supercaps, Vol: 1, Pages: 33-38, ISSN: 2566-6223
Solution‐processable two‐dimensional (2D) materials offer the possibility of manufacturing heterostructures with various properties, creating a way to tune materials towards a specific application. Two different 2D materials, titanium carbide MXene (Ti3C2Tx) and reduced graphene oxide (rGO), have shown promising results for supercapacitor applications due to their flake‐like morphology, high conductivity; and ability to intercalate molecules or ions for charge storage. Here, we demonstrate the self‐assembly of a heterostructure between negatively charged Ti3C2Tx and positively charged modified rGO after shear mixing. Changes in zeta (ζ) potential, X‐ray diffraction (XRD) patterns; and Raman spectra confirm the assembly of this heterostructure. The produced rGO : Ti3C2Tx heterostructures were used as electrodes for supercapacitors. The addition of rGO to Ti3C2Tx allowed some widening of the voltage window. Moreover, due to the synergistic effect of these materials, an increase of the capacitance value was observed. An electrode film composed of rGO (1 wt.%) and Ti3C2Tx (99 wt.%) achieved capacitance values up to 254 F ⋅ g−1 at 2 mV ⋅ s−1 and 193 F ⋅ g−1 at 100 mV ⋅ s−1.
Navarro-Suarez AM, Carretero-Gonzalez J, Casado N, et al., 2018, Hybrid biopolymer electrodes for lithium- and sodium-ion batteries in organic electrolytes, Sustainable Energy and Fuels, Vol: 2, Pages: 836-842, ISSN: 2398-4902
The use of earth abundant and renewable materials is encouraging for the future development of environmentally clean, safe and affordable electrodes for lithium- and sodium-ion batteries. Biohybrid electrodes based on lignin and several conducting polymers have been studied mainly for supercapacitor applications. Here, we show that biohybrid electrodes containing natural lignin and a PEDOT conjugated polymer serve as electroactive materials for lithium- and sodium-ion batteries using liquid organic electrolytes. A reversible discharge capacity of 74 mA h g−1, at C/20 (4 mA g−1) rate, was achieved in the voltage range between 1 V and 4.5 V, with peak values of up to 159 mA h g−1. These properties make the natural lignin–PEDOT hybrid material a suitable organic positive electrode for Li- and Na-ion batteries.
Couly C, Alhabeb M, Van Aken KL, et al., 2018, Asymmetric Flexible MXene-reduced graphene oxide micro-supercapacitor, Advanced Electronic Materials, Vol: 4, Pages: 1-8, ISSN: 2199-160X
Current microfabrication of micro‐supercapacitors often involves multistep processing and delicate lithography protocols. In this study, simple fabrication of an asymmetric MXene‐based micro‐supercapacitor that is flexible, binder‐free, and current‐collector‐free is reported. The interdigitated device architecture is fabricated using a custom‐made mask and a scalable spray coating technique onto a flexible, transparent substrate. The electrode materials are comprised of titanium carbide MXene (Ti3C2Tx) and reduced graphene oxide (rGO), which are both 2D layered materials that contribute to the fast ion diffusion in the interdigitated electrode architecture. This MXene‐based asymmetric micro‐supercapacitor operates at a 1 V voltage window, while retaining 97% of the initial capacitance after ten thousand cycles, and exhibits an energy density of 8.6 mW h cm−3 at a power density of 0.2 W cm−3. Further, these micro‐supercapacitors show a high level of flexibility during mechanical bending. Utilizing the ability of Ti3C2Tx‐MXene electrodes to operate at negative potentials in aqueous electrolytes, it is shown that using Ti3C2Tx as a negative electrode and rGO as a positive one in asymmetric architectures is a promising strategy for increasing both energy and power densities of micro‐supercapacitors.
Navarro-Suarez AM, Van Aken KL, Mathis T, et al., 2018, Development of asymmetric supercapacitors with titanium carbide-reduced graphene oxide couples as electrodes, Electrochimica Acta, Vol: 259, Pages: 752-761, ISSN: 0013-4686
Two-dimensional (2D) nanomaterials have attracted significant interest for supercapacitor applications due to their high surface to volume ratio. Layered 2D materials have the ability to intercalate ions and thus can provide intercalation pseudocapacitance. Properties such as achieving fast ion diffusion kinetics and maximizing the exposure of the electrolyte to the surface of the active material are critical for optimizing the performance of active materials for electrochemical capacitors (i.e. Supercapacitors). In this study, two 2D materials, titanium carbide (Ti3C2Tx) and reduced graphene oxide (rGO), were used as electrode materials for asymmetric supercapacitors, with the resulting devices achieving high capacitance values and excellent capacitance retention in both aqueous and organic electrolytes. This work demonstrates that Ti3C2Tx is a promising electrode material for flexible and high-performance energy storage devices.
Navarro-Suarez AM, Carretero-Gonzalez J, Rojo T, et al., 2017, Poly(quinone-amine)/nanocarbon composite electrodes with enhanced proton storage capacity, Journal of Materials Chemistry A, Vol: 5, Pages: 23292-23298, ISSN: 2050-7496
Novel redox active bi- and terpolymers, containing quinone-amine blocks and wired by nanocarbons have been synthesized and studied as negative electrodes for electrochemical proton storage. Two kinds of diamine (aliphatic and aromatic) were condensed with benzoquinone to enhance the storage capacity. The reaction between the benzoquinone and the diamines created an electroactive polymer displaying pseudo-faradaic proton transfer processes. Besides this transfer process, the aromatic diamine showed an additional reversible redox reaction, between the nitrogen atoms conjugated to the quinone molecule and the hydrogen ions. The incorporation of carbon conductive nanofillers with specific dimensionality provided an additional and straightforward strategy to maximize both the electron conductivity and the proton storage capacity of the polymers. Homogeneous dispersion of nanocarbon redox polymer particles in the composite (along with the creation of a polymer–carbon interphase) was essential, in order to maximize the proton storage capacity. A clear correlation between the nanostructure of the polymer particles, the dimensionality of the nanocarbons and the polymerization process was found. These low-cost redox polymers reached up to 230 mA h g−1 and 75 μA h cm−2 at 0.08 A g−1 in an aqueous-based electrolyte, paving the way for the use of these materials for technologies such as thin-film devices and grid energy storage.
Navarro-Suarez AM, Casado N, Carretero-Gonzalez J, et al., 2017, Full-cell quinone/hydroquinone supercapacitors based on partially reduced graphite oxide and lignin/PEDOT electrodes, Journal of Materials Chemistry A, Vol: 5, Pages: 7137-7143, ISSN: 2050-7496
The development of new, scalable and inexpensive materials for low-cost and sustainable energy storage devices is intensely pursued. The combination of redox active biopolymers with electron conducting polymers has shown enhanced charge storage properties. However, their performance has just been investigated at the electrode level. Herein, we move a step further by assembling full-cell supercapacitors based on natural lignin (Lig) and partially reduced graphite oxide (prGrO) electrode materials. Both materials evidenced that quinone/hydroquinone redox moieties are able to store and release charge reversibly. The redox properties of lignin were improved by combining it with poly(3,4-ethylenedioxythiophene) (PEDOT). Analysis of the capacitive contributions to the charge storage proved that PEDOT enhanced the lignin's capacitive contribution to the current by 22%. The capacitive contributions were equal to 66% and 75% in Lig/PEDOT blend and prGrO electrodes, respectively. We also show for the first time that by distributing equally charges in carbon–biopolymer composite electrodes, a higher capacitance retention, up to 79% after 1000 cycles, is achieved.
Gonzalez-Garcia P, Navarro-Suarez AM, Carretero-Gonzalez J, et al., 2015, Nanostructure, porosity and electrochemical performance of chromium carbide derived carbons, CARBON, Vol: 85, Pages: 38-49, ISSN: 0008-6223
Navarro-Suarez AM, Carretero-Gonzalez J, Roddatis V, et al., 2014, Nanoporous carbons from natural lignin: study of structural-textural properties and application to organic-based supercapacitors, RSC ADVANCES, Vol: 4, Pages: 48336-48343
Navarro-Suarez AM, Hidalgo-Acosta JC, Fadini L, et al., 2011, Electrochemical Oxidation of Hydrogen on Basal Plane Platinum Electrodes in Imidazoliurn Ionic Liquids, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 115, Pages: 11147-11155, ISSN: 1932-7447
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