Elena Gonzalo

• PhD
• PostDoc Position at CIC Energigune

Currently Na-ion battery (NIB) technology is proving a popular area of investigation, in part due to the considerable interest in developing ‘beyond lithium’ battery technology to augment -or in certain situations replace- lithium ion batteries. Consequently, NIBs have begun to gain prominence –in part due to their flexibility and low cost. An exam...

Li3FeF6 has been the focus of research of fluorine-based cathode materials for lithium-ion batteries. Because of the low electronic conductivity of Li3FeF6, the decrease of particle size, by an energy-consuming long-time ball milling process with carbon, is necessary to achieve a high electrochemical performance. The most successful method to enhan...

The search for sodium ion battery cathodes has led to considerable interest in sodium layered oxides due to their attractive properties - e.g. flexibility, versatility, and intrinsically fast Na ion structural diffusion (leading to enhanced rate capability). Based upon our rational approach to material selection (i.e. doping a Mn-rich structure wit...

The electrochemical properties of P2- Na2/3Mn0.8Fe0.1Ti0.1O2 layered oxide, which is a promising cathode material for rechargeable Na-ion batteries (NIBs), are evaluated with with an optimized in-house ionic liquid (IL)-based electrolyte and compared with its performance when using carbonate-based electrolyte. The IL-based system reveals better ele...

The many advantages of Na-ion batteries (NIBs) in terms of availability and cost of raw materials if compared with Li-ion batteries (LIBs) are hindered by the stability of the Na-based electrodes. The most promising NIB positive electrodes are Co- and Ni-free sodium manganese rich layered oxides with general formula NaxMn1-yTMy-zT’MzO2 (y < 0.33, T...

Sodium-ion batteries (NIBs) are emerging as a potentially cheaper alternative to lithium-ion batteries (LIBs) due to the larger abundance of sodium and in some cases the similar intercalation chemistry to LIBs. Here we report the solid state synthesized K-modified P2 Na0.7Mn0.8Mg0.2O2 which adopts hexagonal P63/mmc symmetry. The second charge/disch...

Sodium layered oxide materials have shown excellent performance as cathodes in sodium ion batteries, due to their flexibility, versatility, and intrinsically fast Na ion structural diffusion which leads to enhanced rate capability. In this work, we have examined two strategies to mitigate Jahn-Teller distortion and boost the performance of these sy...

Transition metal (TM) layered oxides constitute one of the most promising family of compounds for the cathode of Na-ion batteries. However, their structural stability at charged state is a critical performance limiting factor, which is believed to be closely related with irreversible TM migration into the Na layers. Nevertheless, experimental evide...

There is growing interest in ionic liquid based electrolytes for Na metal and Na-ion batteries. Here we compare three quite distinct bis(fluorosulfonyl)imide (FSI) anion based ionic liquids with small alkyl phosphonium (trimethyl isobutyl phosphonium, methyl tri-isobutyl: P111i4, P1i4i4i4) or alkoxy ammonium counter cations (N-ethyl-2-(2-methoxyeth...

Sodium layered oxide materials show excellent performance as cathodes in sodium ion batteries, leading to considerable interest in routes to improving their properties. A manganese-rich P2/O3-phase Na2/3Li0.18Mn0.8Fe0.2O2 material is synthesized, from earth abundant precursors, via a solid state-reaction. Its biphasic nature is confirmed by X-ray d...

The structural evolution of electrode materials directly influences the performance of sodium-ion batteries. Here, in situ synchrotron X-ray diffraction is used to investigate the crystal structure evolution of a Mn-rich P2 phase Na2/3Fe0.2Mn0.8O2 cathode. A single phase reaction is found to take place for the majority of the discharge-charge cycle...

Currently, there is increasing interest in developing ‘beyond lithium’ battery technologies to augment, or in certain situations replace, lithium ion batteries (LIBs). Room temperature sodium ion batteries (NIBs) offer an attractive combination of low cost and plentiful constituents and a wide range of phases, structures and stoichiometries availab...

A saturated solution of 2.3 M sodium bis(fluorosulfonyl)imide in trimethyl iso-butyl phosphonium bis(fluorosulfonyl)imide ionic liquid shows a high conductivity (0.94 mScm⁻¹ at 50 °C), low ion association, and a wide operational temperature window (−71 °C–305 °C) making it a promising electrolyte for sodium battery applications. Cycling with P2- an...

Mn-rich layered oxides of P2 Na2/3Mn0.8Fe0.1Ti0.1O2 have been shown to exhibit a remarkably stable electrochemical performance even after exposure to moisture for extended periods of time. Here, a detailed investigation of the electrochemical performance of pristine, protonated, and hydrated electrodes is reported. Neutron powder diffraction and ²³...

Transition metal layered oxides are promising cathode materials for sodium-ion batteries. Phase transitions involving different stacking sequences of the oxide layers often plague the electrochemistry of these materials during cycling, which strongly impacts in their electrochemical performance. However, the underlying mechanisms of these processes...

The development of new insertion electrodes requires an in-depth understanding of the structure–function relationships in order to rationally develop better electrodes. Sodium layered oxides such as P2 Na2/3Fe1/2Mn1/2O2 and Na2/3Fe2/3Mn1/3O2 are particularly interesting due to their performance, price, and low toxicity. Using in situ synchrotron X-...

The recent development and the in-depth analysis of O3-phase Na2/3Fe2/3Mn1/3O2 has enriched the understanding of the overall electrochemical performance relating to the phase transitions during cycling of layered oxide cathodes. In order to understand the correlation between the initial polymorphs, their phase transitions during cycling without bia...

High-performance Mn-rich P2-phase Na2/3Mn0.8Fe0.1Ti0.1O2 is synthesized by a ceramic method, and its stable electrochemical performance is demonstrated. 23Na solid-state NMR confirms the substitution of Ti4+ ions in the transition metal oxide layer and very fast Na+ mobility in the interlayer space. The pristine electrode delivers a second charge/d...

The successful phase separation of P2- and O3-phase Na2/3Fe1/2Mn1/2O2 is demonstrated using co-precipitation method. Although P2-phase displays superior thermodynamic stability at 2/3Na and 1/2Fe:1/2Mn concentration, O3-phase can be stabilized by the means of kinetic control. The electrochemical performance evaluation with half- and full-cells prov...

Cathodes that feature a layered structure are attractive reversible sodium hosts for ambient temperature sodium-ion batteries which may meet the demands for large-scale energy storage devices. However, crystallographic data on these electrodes are limited to equilibrium or quasi-equilibrium information. Here we report the current-dependent structur...

The development of new insertion electrodes in sodium-ion batteries requires an in-depth understanding of the relationship between electrochemical performance and the structural evolution during cycling. To date in situ synchrotron X-ray and neutron diffraction methods appear to be the only probes of in situ electrode evolution at high rates, a cri...

The new title compound is precipitated from a stoichiometric aqueous solution of NiCl2 and NaF (60 °C, 6 h).

A new hydrated sodium nickel fluoride with nominal composition NaNiF3·3H2O was synthesized using an aqueous solution route. Its structure was solved by means of ab initio methods from powder X-ray diffraction and neutron diffraction data. NaNiF3·3H2O crystallizes in the cubic crystal system, space group Pn3̅ with a = 7.91968(4) Å. The framework, de...

Room temperature Na-ion secondary battery has been under focus lately due to its feasibility to compete against already well-established Li-ion secondary battery. Although there are many obstacles to overcome before Na-ion battery becomes commercially available, recent research discoveries corroborate that some of the cathode materials for Na-ion b...

The solid state synthesis and electrochemical characterization of pure P2- and O3-Na2/3Fe2/3Mn1/3O2 have been carried out. Both phases have been characterized with XRD, solid state NMR, and ICP techniques . The initial charge capacity of P2-phase reached 114.7 mAh/g and was followed by a discharge capacity of 151.09 mAh/g within the voltage range o...

Electrochemistry and structural evolution of monoclinic NaNiO2 as a cathode material for Na-ion battery is reported. The initial charge capacity reached 160 mA h g−1 and the following discharge capacity of 114.6 mA h g−1, within the voltage range of 4.0–1.5 V at C/10. The multiple phase transition leading to O′3, P′3, P″3, O″3, and O‴3 stacking typ...

Earth-abundant Na-0.67[Mn1-xMgx] O-2 (0 <= x <= 0.2) cathode materials with the P2 structure have been synthesized as positive electrodes for sodium-ion batteries. Na0.67MnO2 exhibits a capacity of 175 mA h g(-1) with good capacity retention. A Mg content of 5% is sufficient to smooth the charge/ discharge profiles without affecting the capacity, w...

We describe the synthesis and crystal structure of Li 3 MRuO 5 (M ¼ Co and Ni), new rock salt related oxides. Both the oxides crystallize in the layered LiCoO 2 (a-NaFeO 2) structure, as revealed by powder XRD data. Magnetic susceptibility data suggest that the oxidation states of transition metals are Li 3 Co 3+ (ls)Ru 4+ (ls) O 5 (ls ¼ low spin)...

Li3FeF6 has attracted recent interest as a promising positive electrode for rechargeable lithium batteries. The defect chemistry and cation doping behaviour of the α- and β-polymorphs of Li3FeF6 have been investigated by advanced atomistic modelling techniques. Our simulations show good reproduction of both monoclinic (α) and orthorhombic (β) exper...

The β-modification of Li3VF6 is easily prepared following a precipitation reaction at moderate temperature avoiding the high temperature route normally used for preparing related fluorides. Precipitation conditions for Li3VF6 have been optimized for two different alcohols to obtain better electrochemical performances. Temperature has been found to...

An easy scalable reaction is used to prepare nanometric particles of the cryolite Li3FeF6 by precipitation below room temperature. Precipitation of Li3FeF6 in water:2-propanol ratio of 1:3 at 0 °C from a solution of Fe(NO3)3·9H2O, 6HF(aq) and Li2CO3, produces the smallest particles (ca. 20 nm). These particles are agglomerated building up spherical...

The half-metallic ferromagnet K(2)Cr(8)O(16) with the hollandite structure has been chemically modified using soft chemistry methods to increase the average oxidation state of chromium. The synthesis of the parent material has been performed under high pressure/high temperature conditions. Following this, different redox reactions have been carried...

The α-polymorph of Li3FeF6 has been prepared from aqueous-based solution by precipitation under different conditions to obtain small particles. Several alcohols have been used to vary the precipitation media. Among them 2-propanol has been found to provide particles of about 100 nm under controlled conditions of temperature and H2O: R-OH volume rat...

LiFePO4/C nanocomposites have been synthesized by solid state reaction using iron oxalate, ammonium dihydrogen phosphate and lithium carbonate as LiFePO4 precursors while carbon black was used as a carbon source. The mixtures were treated in a tubular oven under argon atmosphere at a temperature of 650∘C and time intervals ranging between 2.5 and 1...

Two materials in the Li–Fe–F system, monoclinic - and orthorhombic , have been investigated as hosts for lithium insertion reactions. Both of them are related to the cryolite-type structure. Although the as-prepared materials do no insert lithium reversibly, decreasing the particle size by mechanical milling in the presence of carbon activates...

The α-polymorph of Li3FeF6 has been obtained at room temperature by a precipitation reaction from aqueous solution. This easy procedure that does not require any further annealing at high temperature yields a white powder with particles sizes ranging from 250 to 400 nm. After proper processing by mechanical milling, particle sizes clearly below 100...

Nanocrystalline (between 30 and 40nm) LiCoO2 and LiCo1−xGaxO2 (0≤x≤0.15) powders have been prepared by using a standard microwave furnace.Depending on the power and irradiation time, nanosized LT-LiCo1−xGaxO2 (cubic) or HT-LiCo1−xGaxO2 (hexagonal) (0≤x≤0.15) materials have been obtained and studied by means of X-ray diffraction, scanning electron m...

Two new cathode materials in the Li-Fe-F system are presented: α-and β-Li 3FeF 6. Both of them are related to the cryolite-type structure. Though the as prepared materials do no intercalate lithium reversibly, decreasing of particle size by mechanical milling in the presence of carbon activate them. Performances of α-Li 3FeF 6 are better since the...

The lithium intercalation chemistry of LiNb6Cl15, a 16 e- Nb-cluster, has been explored in order to obtain new Nb-cluster compounds. As a result, three different phases have been detected. Full de-intercalation of lithium produces Nb6Cl15, a new 15 e- Nb-cluster. The oxidation reaction is reversible since lithium can be intercalated again to produc...

Olivine–LiCoPO4 powders have been processed by mechanical grinding for time periods ranging from 0.5 to 10 h with conductive carbon contents of 0, 8 and 20% (w/w). In all cases the grinding process produces an amorphization of the crystalline materials and decreases both the crystallite and particle sizes. Secondary phases are detected by scanning...