Roughness Factors of Electrodeposited Nanostructured Copper Foams.

Copper-based electrocatalytic materials play a critical role in various electrocatalytic processes, including the electroreduction of carbon dioxide and nitrate. Three-dimensional nanostructured electrodes are particularly advantageous for electrocatalytic applications due to their large surface area, which facilitates charge transfer and mass transport. However, the real surface area (RSA) of electrocatalysts is a crucial parameter that is often overlooked in experimental studies of high-surface-area copper electrodes. In this study, we investigate the roughness factors of electrodeposited copper foams with varying thicknesses and morphologies, obtained using the hydrogen bubble dynamic template technique. Underpotential deposition (UPD) of metal adatoms is one of the most reliable methods for estimating the RSA of highly dispersed catalysts. We aim to illustrate the applicability of UPD of lead for the determination of the RSA of copper deposits with hierarchical porosity. To find the appropriate experimental conditions that allow for efficient minimization of the limitations related to the slow diffusion of lead ions in the pores of the material and background currents of the reduction of traces of oxygen, we explore the effect of lead ion concentration, stirring rate, scan rate, monolayer deposition time and solution pH on the accuracy of RSA estimates. Under the optimized measurement conditions, Pb UPD allowed to estimate roughness factors as high as 400 for 100 µm thick foams, which translates into a specific surface area of ~6 m2·g-1. The proposed measurement protocol may be further applied to estimate the RSA of copper deposits with similar or higher roughness.

NaGaPO4F - a KTiOPO4-structured solid sodium-ion conductor.

Advanced ionic conductors are crucial for a large variety of contemporary technologies spanning solid state ion batteries, fuel cells, gas sensors, water desalination, etc. In this work, we report on a new member of KTiOPO4-structured materials, NaGaPO4F, with sodium-ion conductivity. NaGaPO4F has been obtained for the first time via a facile two-step synthesis consisting of a hydrothermal preparation of an ammonia-based precursor, NH4GaPO4F, followed by an ion exchange reaction with NaNO3. Its crystal structure was precisely refined using a combination of synchrotron X-ray powder diffraction and electron diffraction tomography. The material is thermally stable upon 450 °C showing no significant structural transformations or degradation but only a ∼1% cell volume expansion. Na-ion mobility in NaGaPO4F was investigated by a joint experimental and computational approach comprising solid-state nuclear magnetic resonance (NMR) and density functional theory (DFT). DFT and bond-valence site energy (BVSE) calculations reveal 3D diffusion of sodium in the [GaPO4F] framework with migration barriers amounting to 0.22 and 0.44 eV, respectively, while NMR yields 0.3-0.5 eV that, being coupled with a calculated bandgap of ∼4.25 eV, makes NaGaPO4F a promising fast Na-ion conductor.

NaNbV(PO4)3: Multielectron NASICON-Type Anode Material for Na-Ion Batteries with Excellent Rate Capability.

NASICON-type NaNbV(PO4)3 electrode material synthesized by the Pechini sol-gel technique undergoes a reversible three-electron reaction in a Na-ion cell which corresponds to the Nb5+/Nb4+, Nb4+/Nb3+, and V3+/V2+ redox processes and provides a reversible capacity of 180 mAh·g-1. The sodium insertion/extraction takes place in a narrow potential range at an average potential of 1.55 V versus Na+/Na. Structural characterization by operando and ex situ X-ray diffraction disclosed the reversible evolution of the NaNbV(PO4)3 polyhedron framework during cycling, while XANES measurements in the operando regime confirmed the multielectron transfer upon sodium intercalation/extraction into NaNbV(PO4)3. This electrode material demonstrates extended cycling stability and excellent rate capability maintaining the capacity value of 144 mAh·g-1 at 10 C current rates. It can be regarded as a superior anode material suitable for application in high-power and long-life sodium-ion batteries.

Engendering High Energy Density LiFePO4 Electrodes with Morphological and Compositional Tuning.

Improving the energy density of Li-ion batteries is critical to meet the requirements of electric vehicles and energy storage systems. In this work, LiFePO4 active material was combined with single-walled carbon nanotubes as the conductive additive to develop high-energy-density cathodes for rechargeable Li-ion batteries. The effect of the morphology of the active material particles on the cathodes' electrochemical characteristics was investigated. Although providing higher packing density of electrodes, spherical LiFePO4 microparticles had poorer contact with an aluminum current collector and showed lower rate capability than plate-shaped LiFePO4 nanoparticles. A carbon-coated current collector helped enhance the interfacial contact with spherical LiFePO4 particles and was instrumental in combining high electrode packing density (1.8 g cm-3) with excellent rate capability (100 mAh g-1 at 10C). The weight percentages of carbon nanotubes and polyvinylidene fluoride binder in the electrodes were optimized for electrical conductivity, rate capability, adhesion strength, and cyclic stability. The electrodes that were formulated with 0.25 wt.% of carbon nanotubes and 1.75 wt.% of the binder demonstrated the best overall performance. The optimized electrode composition was used to formulate thick free-standing electrodes with high energy and power densities, achieving the areal capacity of 5.9 mAh cm-2 at 1C rate.

Development of vanadium-based polyanion positive electrode active materials for high-voltage sodium-based batteries.

Polyanion compounds offer a playground for designing prospective electrode active materials for sodium-ion storage due to their structural diversity and chemical variety. Here, by combining a NaVPO4F composition and KTiOPO4-type framework via a low-temperature (e.g., 190 °C) ion-exchange synthesis approach, we develop a high-capacity and high-voltage positive electrode active material. When tested in a coin cell configuration in combination with a Na metal negative electrode and a NaPF6-based non-aqueous electrolyte solution, this cathode active material enables a discharge capacity of 136 mAh g-1 at 14.3 mA g-1 with an average cell discharge voltage of about 4.0 V. Furthermore, a specific discharge capacity of 123 mAh g-1 at 5.7 A g-1 is also reported for the same cell configuration. Through ex situ and operando structural characterizations, we also demonstrate that the reversible Na-ion storage at the positive electrode occurs mostly via a solid-solution de/insertion mechanism.

Rational Screening of High-Voltage Electrolytes and Additives for Use in LiNi0.5Mn1.5O4-Based Li-Ion Batteries.

In the present work, we focus onthe experimental screening of selected electrolytes, which have been reported earlier in different works, as a good choice for high-voltage Li-ion batteries. Twenty-four solutions were studied by means of their high-voltage stability in lithium half-cells with idle electrode (C+PVDF) and the LiNi0.5Mn1.5O4-based composite as a positive electrode. Some of the solutions were based on the standard 1 M LiPF6 in EC:DMC:DEC = 1:1:1 with/without additives, such as fluoroethylene carbonate, lithium bis(oxalate) borate and lithium difluoro(oxalate)borate. More concentrated solutions of LiPF6 in EC:DMC:DEC = 1:1:1 were also studied. In addition, the solutions of LiBF4 and LiPF6 in various solvents, such as sulfolane, adiponitrile and tris(trimethylsilyl) phosphate, atdifferent concentrations were investigated. A complex study, including cyclic voltammetry, galvanostatic cycling, impedance spectroscopy and ex situ PXRD and EDX, was applied for the first time to such a wide range of electrolytesto provide an objective assessment of the stability of the systems under study. We observed a better anodic stability, including a slower capacity fading during the cycling and lower charge transfer resistance, for the concentrated electrolytes and sulfolane-based solutions. Among the studied electrolytes, the concentrated LiPF6 in EC:DEC:DMC = 1:1:1 performed the best, since it provided both low SEI resistance and stability of the LiNi0.5Mn1.5O4 cathode material.

Revisited Ti2Nb2O9 as an Anode Material for Advanced Li-Ion Batteries.

Ti2Nb2O9 with a tunnel-type structure is considered as a perspective negative electrode material for Li-ion batteries (LIBs) with theoretical capacity of 252 mAh g-1 corresponding to one-electron reduction/oxidation of Ti and Nb, but only ≈160 mAh g-1 has been observed practically. In this work, highly reversible capacity of 200 mAh g-1 with the average (de)lithiation potential of 1.5 V vs Li/Li+ is achieved for Ti2Nb2O9 with pseudo-2D layered morphology obtained via thermal decomposition of the NH4TiNbO5 intermediate prepared by K+→ H+→ NH4+ cation exchange from KTiNbO5. Using operando synchrotron powder X-ray diffraction (SXPD), single-phase (de)lithiation mechanism with 4.8% unit cell volume change is observed. Operando X-ray absorption near-edge structure (XANES) experiment revealed simultaneous Ti4+/Ti3+ and Nb5+/Nb4+ reduction/oxidation within the whole voltage range. Li+ migration barriers for Ti2Nb2O9 along [010] direction derived from density functional theory (DFT) calculations are within the 0.15-0.4 eV range depending on the Li content that is reflected in excellent C-rate capacity retention. Ti2Nb2O9 synthesized via the ion-exchange route appears as a strong contender to widely commercialized Ti-based negative electrode material Li4Ti5O12 in the next generation of high-performance LIBs.

α-TiPO4 as a Negative Electrode Material for Lithium-Ion Batteries.

To realize high-power performance, lithium-ion batteries require stable, environmentally benign, and economically viable noncarbonaceous anode materials capable of operating at high rates with low strain during charge-discharge. In this paper, we report the synthesis, crystal structure, and electrochemical properties of a new titanium-based member of the MPO4 phosphate series adopting the α-CrPO4 structure type. α-TiPO4 has been obtained by thermal decomposition of a novel hydrothermally prepared fluoride phosphate, NH4TiPO4F, at 600 °C under a hydrogen atmosphere. The crystal structure of α-TiPO4 is refined from powder X-ray diffraction data using a Rietveld method and verified by electron diffraction and high-resolution scanning transmission electron microscopy, whereas the chemical composition is confirmed by IR, energy-dispersive X-ray, electron paramagnetic resonance, and electron energy loss spectroscopies. Carbon-coated α-TiPO4/C demonstrates reversible electrochemical activity ascribed to the Ti3+/Ti2+ redox transition delivering 125 mAh g-1 specific capacity at C/10 in the 1.0-3.1 V versus Li+/Li potential range with an average potential of ∼1.5 V, exhibiting good rate capability and stable cycling with volume variation not exceeding 0.5%. Below 0.8 V, the material undergoes a conversion reaction, further revealing capacitive reversible electrochemical behavior with an average specific capacity of 270 mAh g-1 at 1C in the 0.7-2.9 V versus Li+/Li potential range. This work suggests a new synthesis route to metastable titanium-containing phosphates holding prospective to be used as negative electrode materials for metal-ion batteries.

Phase Transitions in the "Spinel-Layered" Li1+xNi0.5Mn1.5O4 (x = 0, 0.5, 1) Cathodes upon (De)lithiation Studied with Operando Synchrotron X-ray Powder Diffraction.

"Spinel-layered" Li1+xNi0.5Mn1.5O4 (x = 0, 0.5, 1) materials are considered as a cobalt-free alternative to currently used positive electrode (cathode) materials for Li-ion batteries. In this work, their electrochemical properties and corresponding phase transitions were studied by means of synchrotron X-ray powder diffraction (SXPD) in operando regime. Within the potential limit of 2.2-4.9 V vs. Li/Li+ LiNi0.5Mn1.5O4 with cubic spinel type structure demonstrates the capacity of 230 mAh·g-1 associated with three first-order phase transitions with significant total volume change of 8.1%. The Li2Ni0.5Mn1.5O4 material exhibits similar capacity value and subsequence of the phase transitions of the spinel phase, although the fraction of the spinel-type phase in this material does not exceed 30 wt.%. The main component of Li2Ni0.5Mn1.5O4 is Li-rich layered oxide Li(Li0.28Mn0.64Ni0.08)O2, which provides nearly half of the capacity with very small unit cell volume change of 0.7%. Lower mechanical stress associated with Li (de)intercalation provides better cycling stability of the spinel-layered complex materials and makes them more perspective for practical applications compared to the single-phase LiNi0.5Mn1.5O4 high-voltage cathode material.

Development of the basics of complex technology for capturing and disposing of heavy metals from surface drains of cities.

For the first time, the basics of waste-free technology for capturing heavy metal ions from urban surface runoff from residential areas of the city with the final utilization of the regenerate were developed. The technology eliminates the subsequent contamination of the lithosphere and atmosphere by regeneration products. The expediency of using fibrous chemosorbents (cationic and polyampholyte) for capturing heavy metal ions from urban surface runoff of residential areas of megalopolises has been justified because of possibility of recycling heavy metal ions and regenerating the sorbent. Model solutions of Fe, Cu, Zn, Pb salts, as well as samples of solutions of real surface effluents were studied. Small experimental samples of filters of various designs were designed and manufactured. The filters were tested at a functioning treatment facility. It was demonstrated that the content of Fe3+, Cu2+, Zn2+, and Pb2+ ions in real surface effluents decreased by 1.4-7 times after passing the effluents even through these small experimental filters. The expediency and possibility of recycling the regenerate as inorganic pigments for the paint industry is shown.

Li-based layered nickel-tin oxide obtained through electrochemically-driven cation exchange.

The Li-based layered nickel-tin oxide Li0.35Na0.07Ni0.5Sn0.5O2 has been synthesized via electrochemically-driven Li+ for Na+ exchange in O3-NaNi0.5Sn0.5O2. The crystal structure of Li0.35Na0.07Ni0.5Sn0.5O2 was Rietveld-refined from powder X-ray diffraction data (a = 3.03431(7) Å, c = 14.7491(8) Å, S. G. R3̄m). It preserves the O3 stacking sequence of the parent compound, but with ∼13% lower unit cell volume. Electron diffraction and atomic-resolution scanning transmission electron microscopy imaging revealed short-range Ni/Sn ordering in both the pristine and Li-exchanged materials that is similar to the "honeycomb" Li/M ordering in Li2MO3 oxides. As supported by bond-valence sum and density functional theory calculations, this ordering is driven by charge difference between Ni2+ and Sn4+ and the necessity to maintain balanced bonding for the oxygen anions. Li0.35Na0.07Ni0.5Sn0.5O2 demonstrates reversible electrochemical (de)intercalation of ∼0.21 Li+ in the 2.8-4.3 V vs. Li/Li+ potential range. Limited electrochemical activity is attributed to a formation of the surface Li/Ni disordered rock-salt barrier layer as the Li+ for Na+ exchange drastically reduces the energy barrier for the Li/Ni antisite disorder.

Solid state chemistry for developing better metal-ion batteries.

Metal-ion batteries are key enablers in today's transition from fossil fuels to renewable energy for a better planet with ingeniously designed materials being the technology driver. A central question remains how to wisely manipulate atoms to build attractive structural frameworks of better electrodes and electrolytes for the next generation of batteries. This review explains the underlying chemical principles and discusses progresses made in the rational design of electrodes/solid electrolytes by thoroughly exploiting the interplay between composition, crystal structure and electrochemical properties. We highlight the crucial role of advanced diffraction, imaging and spectroscopic characterization techniques coupled with solid state chemistry approaches for improving functionality of battery materials opening emergent directions for further studies.

Protective Spinel Coating for Li1.17Ni0.17Mn0.50Co0.17O2 Cathode for Li-Ion Batteries through Single-Source Precursor Approach.

The Li1.17Ni0.17Mn0.50Co0.17O2 Li-rich NMC positive electrode (cathode) for lithium-ion batteries has been coated with nanocrystals of the LiMn1.5Co0.5O4 high-voltage spinel cathode material. The coating was applied through a single-source precursor approach by a deposition of the molecular precursor LiMn1.5Co0.5(thd)5 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) dissolved in diethyl ether, followed by thermal decomposition at 400 °C inair resulting in a chemically homogeneous cubic spinel. The structure and chemical composition of the coatings, deposited on the model SiO2 spheres and Li-rich NMC crystallites, were analyzed using powder X-ray diffraction, electron diffraction, high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy-dispersive X-ray (EDX) mapping. The coated material containing 12 wt.% of spinel demonstrates a significantly improved first cycle Coulombic efficiency of 92% with a high first cycle discharge capacity of 290 mAhg-1. The coating also improves the capacity and voltage retention monitored over 25 galvanostatic charge-discharge cycles, although a complete suppression of the capacity and voltage fade is not achieved.

Titanium-based potassium-ion battery positive electrode with extraordinarily high redox potential.

The rapid progress in mass-market applications of metal-ion batteries intensifies the development of economically feasible electrode materials based on earth-abundant elements. Here, we report on a record-breaking titanium-based positive electrode material, KTiPO4F, exhibiting a superior electrode potential of 3.6 V in a potassium-ion cell, which is extraordinarily high for titanium redox transitions. We hypothesize that such an unexpectedly major boost of the electrode potential benefits from the synergy of the cumulative inductive effect of two anions and charge/vacancy ordering. Carbon-coated electrode materials display no capacity fading when cycled at 5C rate for 100 cycles, which coupled with extremely low energy barriers for potassium-ion migration of 0.2 eV anticipates high-power applications. Our contribution shows that the titanium redox activity traditionally considered as "reducing" can be upshifted to near-4V electrode potentials thus providing a playground to design sustainable and cost-effective titanium-containing positive electrode materials with promising electrochemical characteristics.

α-VPO4: A Novel Many Monovalent Ion Intercalation Anode Material for Metal-Ion Batteries.

In this paper, we report on a novel α-VPO4 phosphate adopting the α-CrPO4 type structure as a promising anode material for rechargeable metal-ion batteries. Obtained by heat treatment of a structurally related hydrothermally prepared KTiOPO4-type NH4VOPO4 precursor under reducing conditions, the α-VPO4 material appears stable in a wide temperature range and possesses an interesting "sponged" needle-like particle morphology. The electrochemical performance of α-VPO4 as the anode material was examined in Li-, Na-, and K-based cells. The carbon-coated α-VPO4/C composite exhibits 185, 110, and 37 mA h/g specific capacities respectively at the first discharge and around 120, 80, and 30 mA h/g at consecutive cycles at a C/10 rate. The considerable capacity drop after the first cycle in Li and Na cells is presumably due to irreversible alkali ion consumption taking place upon alkali-ion de/insertion. The EDX analysis of the recovered electrodes revealed an uptake of ∼23% of Na after the first discharge with significant cell parameter alteration validated by operando XRD measurements. In contrast to the known ß-VPO4 anode materials, both Li and Na de/insertion into the new α-VPO4 proceed via an intercalation mechanism with the parent structural framework preserved but not via a conversion mechanism. The dimensionality of alkali-ion migration pathways and diffusion energy barriers was analyzed by the BVEL approach. Na-ion diffusion coefficients measured by the potentiostatic intermittent titration technique are in the range of (0.3-1.0)·10-10 cm2/s, anticipating α-VPO4 as a prospective high-power anode material for Na-ion batteries.

The effects of adverse drug reactions on patients' satisfaction: Evidence from publicly available data on Tamiflu (oseltamivir).

BACKGROUND: Despite the fact that user-generated data are widely used in medical informatics in general and for revealing side-effects of various pharmaceuticals in particular, recent studies have focused merely on methods of extracting information on side effects from unstructured or semi-structured reviews of specific medications without linking side effects to any outcomes. OBJECTIVES: In this study we demonstrate how user-generated online content on side effects experienced by patients while taking a pharmaceutical product can be used to do research after the drug has been introduced to the market, thus allowing to complement the results of official clinical studies and market research. In particular, we concentrate on revealing the contribution of various side effects to reported customer satisfaction with Tamiflu, a popular antiviral drug. METHODS: Publicly available data from an online platform with reviews from patients are used as an input to the analysis that applies statistical and machine learning methods (multivariate logit models and classification trees) to investigate the relationships of side effects to demographic characteristics and to the overall satisfaction with the medication. RESULTS: We prioritized side effects of Tamiflu based on the significance of their association with patient's ratings published at one of the well-known drug discussion forums. Among all types of side effects used in our study, the neuropsychiatric symptoms and body pain are the most influential, followed by skin problems. Specific combinations of side-effects that are associated with low satisfaction were detected. CONCLUSION: The proposed analytical approach can help pharmaceutical companies to improve their products and/or medical guidelines associated with their products and figure out fighting which adverse effects should be given a priority from the customer satisfaction perspective.

Oxygen surface exchange and diffusion in Pr1.75Sr0.25Ni0.75Co0.25O4±Î´.

Oxygen surface exchange and diffusion in Pr1.75Sr0.25Ni0.75Co0.25O4±Î´ have been investigated using two methods: pulsed isotope exchange (PIE) and oxygen isotope exchange with gas phase equilibration (IE GPE). Oxygen surface exchange kinetics is considered in the framework of two-step models including two consecutive stages: dissociative adsorption of oxygen and incorporation of oxygen adatoms into the crystal lattice. The rates of oxygen heterogeneous exchange (rH) as well as the rates of dissociative adsorption (ra) and oxygen incorporation (ri) have been calculated. The applicability of the two-step model is discussed based on the concept of a novel two-step mechanism with distributed rates of dissociative adsorption and incorporation of oxygen. It is shown that the two-step model can be applicable for the description of oxygen exchange kinetics in Pr1.75Sr0.25Ni0.75Co0.25O4±Î´ only at temperatures below 750 °C. Above this temperature, only the statistical model with distributed rates can be used. At low temperatures (<750 °C), the oxygen incorporation rate is found to be smaller than the rate of oxygen dissociative adsorption. Thus, under these experimental conditions the stage of oxygen incorporation is considered to be rate-determining. When increasing the temperature, the difference between ra and ri decreases and the stages become competing. The oxygen isotope exchange kinetic profiles obtained using the IE GPE method are found to be complicated and include a surface exchange stage as well as at least two diffusion relaxation processes. The reasons for the existence of these two processes are discussed.

An electrochemical cell with sapphire windows for operando synchrotron X-ray powder diffraction and spectroscopy studies of high-power and high-voltage electrodes for metal-ion batteries.

A new multi-purpose operando electrochemical cell was designed, constructed and tested on the Swiss-Norwegian Beamlines BM01 and BM31 at the European Synchrotron Radiation Facility. Single-crystal sapphire X-ray windows provide a good signal-to-noise ratio, excellent electrochemical contact because of the constant pressure between the electrodes, and perfect electrochemical stability at high potentials due to the inert and non-conductive nature of sapphire. Examination of the phase transformations in the Li1-xFe0.5Mn0.5PO4 positive electrode (cathode) material at C/2 and 10C charge and discharge rates, and a study of the valence state of the Ni cations in the Li1-xNi0.5Mn1.5O4 cathode material for Li-ion batteries, revealed the applicability of this novel cell design to diffraction and spectroscopic investigations of high-power/high-voltage electrodes for metal-ion batteries.

The Role of Semilabile Oxygen Atoms for Intercalation Chemistry of the Metal-Ion Battery Polyanion Cathodes.

Using the orthorhombic layered Na2FePO4F cathode material as a model system we identify the bonding of the alkali metal cations to the semilabile oxygen atoms as an important factor affecting electrochemical activity of alkali cations in polyanion structures. The semilabile oxygens, bonded to the P and alkali cations, but not included into the FeO4F2 octahedra, experience severe undercoordination upon alkali cation deintercalation, causing an energy penalty for removing the alkali cations located in the proximity of such semilabile oxygens. Desodiation of Na2FePO4F proceeds through a two-phase mechanism in the Na-ion cell with a formation of an intermediate monoclinic Na1.55FePO4F phase with coupled Na/vacancy and Fe2+/Fe3+ charge ordering at 50% state of charge. In contrast, desodiation of Na2FePO4F in the Li-ion cell demonstrates a sloping charge profile suggesting a solid solution mechanism without formation of a charge-ordered intermediate phase. A combination of a comprehensive crystallographic study and extensive DFT-based calculations demonstrates that the difference in electrochemical behavior of the alkali cation positions is largely related to the different number of the nearest neighbor semilabile oxygen atoms, influencing their desodiation potential and accessibility for the Na/Li chemical exchange, triggering coupled alkali cation-vacancy ordering and Fe2+/Fe3+ charge ordering, as well as switching between the "solid solution" and "two-phase" charging mechanistic regimes.

Lithium Ion Coupled Electron-Transfer Rates in Superconcentrated Electrolytes: Exploring the Bottlenecks for Fast Charge-Transfer Rates with LiMn2O4 Cathode Materials.

The charge-transfer kinetics of lithium ion intercalation into LixMn2O4 cathode materials was examined in dilute and concentrated aqueous and carbonate LiTFSI solutions using electrochemical methods. Distinctive trends in ion intercalation rates were observed between water-based and ethylene carbonate/diethyl carbonate solutions. The influence of the solution concentration on the rate of lithium ion transfer in aqueous media can be tentatively attributed to the process associated with Mn dissolution, whereas in carbonate solutions the rate is influenced by the formation of a concentration-dependent solid electrolyte interface (SEI). Some indications of SEI layer formation at electrode surfaces in carbonate solutions after cycling are detected by X-ray photoelectron spectroscopy. The general consequences related to the application of superconcentrated electrolytes for use in advanced energy storage cathodes are outlined and discussed.