Browsing by Keyword "Electrochemistry"
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Item Effect of chemical environment on the dynamics of water confined in calcium silicate minerals: Natural and synthetic tobermorite(2015-05-05) Monasterio, Manuel; Gaitero, Juan J.; Manzano, Hegoi; Dolado, Jorge S.; Cerveny, Silvina; Tecnalia Research & Innovation; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓNConfined water in the slit mesopores of the mineral tobermorite provides an excellent model system for analyzing the dynamic properties of water confined in cement-like materials. In this work, we use broadband dielectric spectroscopy (BDS) to analyze the dynamic of water entrapped in this crystalline material. Two samples, one natural and one synthetic, were analyzed, and despite their similar structure, the motion of confined water in their zeolitic cavity displays considerably different behavior. The water dynamics splits into two different behaviors depending on the chemical nature of the otherwise identical structural environment: water molecules located in areas where the primary building units are SiO4 relax slowly compared to water molecules located in cavities built with both AlO4 and SiO4. Compared to water confined in regular porous systems, water restricted in tobermorite is slower, indicating that the mesopore structure induces high disorder in the water structure. A comparison with water confined in the C-S-H gel is also discussed in this work. The strong dynamical changes in water due to the presence of aluminum might have important implications in the chemical transport of ions within hydrated calcium silicates, a process that governs the leaching and chemical degradation of cement.Item Evaluation of the electrochemical performance of electrospun transition metal oxide-based electrode nanomaterials for water CDI applications(2019-06-20) Santangelo, Saveria; Pantò, Fabiola; Triolo, Claudia; Stelitano, Sara; Frontera, Patrizia; Fernández-Carretero, Francisco; Rincon, Inés; Azpiroz, Patxi; García-Luis, Alberto; Belaustegui, Yolanda; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; VALORIZACIÓN DE RESIDUOSComposite fibrous materials based on (graphene-enriched) nitrogen-doped carbon/transition metal oxides were produced by electrospinning and their physicochemical properties were thoroughly investigated by a combination of characterisation techniques. The electrochemical behaviour of the electrodes prepared with them was evaluated in view of their use in the capacitive deionisation of saline water. The morphology of the materials reminded of usnea florida lichens, wheat ears, sea sponges and noodles and depended on the transition metal (Mn, Fe, Ti or Zn). The morphology and the relative amount (14.1–22.2 wt%) of the surface nitrogen and carbon-bonded oxygen functional species, beneficial to wettability and involving pseudocapacitive processes, had strong impact on the specific capacitance (43.7–67.4 F g−1, at 5 m V s−1 scan rate), whereas also the specific micropore volume (0.4–5.6 mm3 g−1) affected the effective areal capacitance of the electrodes (1.2–6.0 F m−2, at 5 mV s−1). Ion storage in the composite materials occurred via a mixed capacitive/pseudocapacitive process. Hence, increasing the content of the oxide (from 24.6 to 56.7 wt%), thanks to the fast-reversible redox reactions at or near surface it involves, partly compensated for the growing hindrance to diffusion encountered by the ions (hampered electrostatic adsorption) as the scan rate increased from 5 to 100 mV s−1.Item Monolithic All-Solid-State High-Voltage Li-Metal Thin-Film Rechargeable Battery(2022-10-24) Madinabeitia, Iñaki; Rikarte, Jokin; Etxebarria, Ane; Baraldi, Giorgio; Fernández-Carretero, Francisco José; Garbayo, Iñigo; Cid, Rosalía; García-Luis, Alberto; Muñoz-Márquez, Miguel Ángel; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENOThe substitution of an organic liquid electrolyte with lithium-conducting solid materials is a promising approach to overcome the limitations associated with conventional lithium-ion batteries. These constraints include a reduced electrochemical stability window, high toxicity, flammability, and the formation of lithium dendrites. In this way, all-solid-state batteries present themselves as ideal candidates for improving energy density, environmental friendliness, and safety. In particular, all-solid-state configurations allow the introduction of compact, lightweight, high-energy-density batteries, suitable for low-power applications, known as thin-film batteries. Moreover, solid electrolytes typically offer wide electrochemical stability windows, enabling the integration of high-voltage cathodes and permitting the fabrication of higher-energy-density batteries. A high-voltage, all-solid-state lithium-ion thin-film battery composed of LiNi0.5Mn1.5O4 cathode, a LiPON solid electrolyte, and a lithium metal anode has been deposited layer by layer on low-cost stainless-steel current collector substrates. The structural and electrochemical properties of each electroactive component of the battery had been analyzed separately prior to the full cell implementation. In addition to a study of the internal solid–solid interface, comparing them was done with two similar cells assembled using conventional lithium foil, one with thin-film solid electrolyte and another one with thin-film solid electrolyte plus a droplet of LP30 liquid electrolyte. The thin-film all-solid state cell developed in this work delivered 80.5 mAh g–1 in the first cycle at C/20 and after a C-rate test of 25 cycles at C/10, C/5, C/2, and 1C and stabilized its capacity at around 70 mAh g–1 for another 12 cycles prior to the start of its degradation. This cell reached gravimetric and volumetric energy densities of 333 Wh kg–1 and 1,212 Wh l–1, respectively. Overall, this cell showed a better performance than its counterparts assembled with Li foil, highlighting the importance of the battery interface control.Item Platinum Group Metals Recovery Using Secondary Raw Materials (PLATIRUS): Project Overview with a Focus on Processing Spent Autocatalyst: Project overview with a focus on processing spent autocatalyst(2021-01) Nicol, Giovanna; Goosey, Emma; Yıldız, Deniz Şanlı; Loving, Elaine; Nguyen, Viet Tu; Riaño, Sofía; Yakoumis, Iakovos; Martinez, Ana Maria; Siriwardana, Amal; Unzurrunzaga, Ainhoa; Spooren, Jeroen; Atia, Thomas Abo; Michielsen, Bart; Dominguez-Benetton, Xochitl; Lanaridi, Olga; Yildiz, Deniz Sanli; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOSPLATInum group metals Recovery Using Secondary raw materials (PLATIRUS), a European Union (EU) Horizon 2020 project, aims to address the platinum group metal (pgm) supply security within Europe by developing novel and greener pgm recycling processes for autocatalysts, mining and electronic wastes. The initial focus was on laboratory-scale research into ionometallurgical leaching, microwave assisted leaching, solvometallurgical leaching, liquid separation, solid phase separation, electrodeposition, electrochemical process: gas-diffusion electrocrystallisation and selective chlorination. These technologies were evaluated against key performance indicators (KPIs) including recovery, environmental impact and process compatibility; with the highest scoring technologies combining to give the selected PLATIRUS flowsheet comprising microwave assisted leaching, non-conventional liquid-liquid extraction and gas-diffusion electrocrystallisation. Operating in cascade, the PLATIRUS flowsheet processed ~1.3 kg of spent milled autocatalyst and produced 1.2 g palladium, 0.8 g platinum and 0.1 g rhodium in nitrate form with a 92‐99% purity. The overall recoveries from feedstock to product were calculated as 46 ± 10%, 32 ± 8% and 27 ± 3% for palladium, platinum and rhodium respectively. The recycled pgm has been manufactured into autocatalysts for validation by end users. This paper aims to be a project overview, an in‐depth technical analysis into each technology is not included. It summarises the most promising technologies explored, the technology evaluation, operation of the selected technologies in cascade, the planned recycled pgm end user validation and the next steps required to ready the technologies for implementation and to further validate their potential.Item Specific bioanalytical optical and photoelectrochemical assays for detection of methanol in alcoholic beverages(2018-03-15) Barroso, Javier; Díez-Buitrago, Beatriz; Saa, Laura; Möller, Marco; Briz, Nerea; Pavlov, Valeri; Tecnalia Research & Innovation; SGMethanol is a poison which is frequently discovered in alcoholic beverages. Innovative methods to detect methanol in alcoholic beverages are being constantly developed. We report for the first time a new strategy for the detection of methanol using fluorescence spectroscopy and photoelectrochemical (PEC) analysis. The analytical system is based on the oxidation of cysteine (CSH) with hydrogen peroxide (H2O2) enzymatically generated by alcohol oxidase (AOx). H2O2 oxidizes capping agent CSH, modulating the growth of CSH-stabilized cadmium sulphide quantum dots (CdS QDs). Disposable screen-printed carbon electrodes (SPCEs) modified with a conductive osmium polymer (Os-PVP) complex were employed to quantify resulting CdS QDs. This polymer facilitates the “wiring” of in situ enzymatically generated CdS QDs, which photocatalyze oxidation of 1-thioglycerol (TG), generating photocurrent as the readout signal. Likewise, we proved that our systems did not suffer from interference by ethanol. The PEC assays showed better sensitivity than conventional methods, covering a wide range of potential applications for methanol quantification.Item Water-Facilitated Electrodeposition of Neodymium in a Phosphonium-Based Ionic Liquid(2019-01-17) Sanchez-Cupido, Laura; Pringle, Jennifer M.; Siriwardana, Amal L.; Unzurrunzaga, Ainhoa; Hilder, Matthias; Forsyth, Maria; Pozo-Gonzalo, Cristina; VALORIZACIÓN DE RESIDUOS; Tecnalia Research & InnovationRare-earth metals are considered critical metals due to their extensive use in energy-related applications such as wind turbines and nickel-metal hybrid batteries found in hybrid electrical vehicles. A key drawback of the current processing methods includes the generation of large amounts of toxic and radioactive waste. Thus the efficient recovery of these valuable metals as well as cleaner processing methods are becoming increasingly important. Here we report on a clean electrochemical route for neodymium (Nd) recovery from [P 6,6,6,14 ][TFSI], trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide which is amplified three times by the presence of water, as evidenced by the cathodic current density and thicker deposits. The role of Nd salt concentrations and water content as an additive in the electrochemistry of Nd 3+ in [P 6,6,6,14 ][TFSI] has been studied. The presence of metallic neodymium in the deposits has been confirmed by X-ray photoelectron spectroscopy.