Neutron diffraction, thermogravimetry, and high temperature solution calorimetry measurements reveal insights into proton and oxygen-ion kinetics in BaCo 0.4 Fe 0.4 Zr 0.2− X Y X O 3− δ triple ionic–electronic conducting ceramics.

Bipolar membranes (BPMs) emerge as a valuable component in novel energy conversion devices utilizing a water-splitting reaction within BPMs. However, the opposite process, proton and hydroxide recombination (forward bias), remains challenging to control due to its strong dependence on the electrolyte composition. Even minor contamination of acid and base solutions by salt can significantly compromise the BPM performance. This study examines the impact of salt contamination on the BPM performance under forward bias. The results reveal that, during neutralization, salt ions accumulate near the BPM junction, hindering H+ and OH- transport toward the catalytic interface. Notably, the anion-exchange layer exhibits a high sensitivity to salt contamination in the base solution, with active site swapping between OH- and anions emerging as the rate-determining step. The extent of this transport limitation depends on the acid/base-to-salt ratio. To address this issue, mitigation strategies are explored, including asymmetric BPMs. Reducing the thickness of the anion-exchange layer significantly enhances OH- mobility, thereby increasing the limiting current density of neutralization in salt-contaminated electrolytes. These insights offer a deeper understanding of mass-transport limitations in BPMs and highlight pathways to optimize performance in energy conversion applications.

We present magnesium alginate as an aqueous polymer electrolyte for use in magnesium batteries. Alginates are polysaccharides extracted from algae, which form hydrogel materials upon interaction with divalent and trivalent cations. They are renewable, non-toxic, biocompatible materials that are widely used in the food and pharmaceutical industries. Mg2+ is weakly bound to an alginate polymer, which results in a hydrogel-like material that contains mobile magnesium ions. We propose that this is the ideal situation for an electrolyte that behaves in a similar way as a ‘water-in-salt’ system. Magnesium alginate was successfully synthesized and characterized by FTIR, XRD, and PDF. Ionic conductivity was measured with EIS measurements; a 2 wt% magnesium electrolyte shows a conductivity of 1.8 mS/cm. During conductivity experiments, we noticed the formation of a black layer on magnesium electrodes, which can improve the ionic conductivity between the electrodes. We carefully characterized this layer with XPS and saw that it mainly consists of alginate derivatives.

Ceramic solid-state batteries (SSBs) are considered a viable alternative to lithium-ion batteries with liquid electrolytes, as they offer greater safety at the cell level. The Li7La3Zr2O12 garnet (LLZO) is a promising solid electrolyte for SSBs due to its stability with lithium metal anode and its good ionic conductivity of up to 2 mS cm-1. However, scalable and economically feasible techniques for producing LLZO-based batteries are required to make them competitive in the market. Tape casting is an industrially scalable process for producing customizable ceramic components. Successful implementation of this method requires a deep understanding of the transformation of the LLZO powder during the whole process chain, especially the effects of Li loss due to air and protic solvents interaction as well as Li evaporation during sintering. In this talk, a novel approach for fabricating thin LLZO ceramic separators by tape casting will be presented, in which lithium saltis used as a lithium mediator source in different process steps to optimize the separator properties. Using XRD, Raman spectroscopy, NMR spectroscopy, and SEM, we systematically investigate the effects of material composition and process conditions on the compositional and electrochemical performance of tape-cast LLZO separators in symmetric cells. This research provides important insights for optimizing the manufacturing process and enables the development of high-performance LLZO ceramic separators for all-solid-state batteries.

The upcoming energy transition requires not only renewable energy sources but also novel electricity storage systems such as batteries. Despite Li-ion batteries being the main storage systems, other batteries have been proposed to fulfil the requirements on safety, costs, and resource availability. Moving away from lithium, materials such as sodium, magnesium, zinc, and calcium are being considered. Water-based electrolytes are known for their improved safety, environmentally friendliness, and affordability. The key, however, is how to utilize the negative metal electrode, as using water-based electrolytes with these metals becomes an issue with respect to oxidation and/or dendrite formation. This work studied magnesium, where we aimed to determine if it can be electrochemically deposited in aqueous solutions with alginate-based additives to protect the magnesium. In order to do so, atomic force microscopy was used to research the morphological structure of magnesium deposition at the local scale by using a probe—the tip of a cantilever—as the active electrode, during charging and discharging. The second goal of using the AFM probe technology for magnesium deposition and stripping was an extension of our previous study in which we investigated, for lithium, whether it is possible to measure ion current and perform nonfaradaic impedance measurements at the local scale. The work presented here shows that this is possible in a relatively simple way because, with magnesium, no dendrite formation occurs, which hinders the stripping process.

Ceramic membranes made of garnet Li7Zr3La2O12 (LLZO) are promising separators for lithium metal batteries because they are chemically stable to lithium metal and can resist the growth of lithium dendrites. Free-standing garnet separators can be produced on a large scale using tape casting and sintering slurries containing LLZO powder, but the quality of the separators is severely compromized by the protonation of the moisture-sensitive LLZO during processing and the irreversible loss of lithium during sintering. In this work, an approach is presented to mitigate the degradation of the LLZO and produce high quality separators using Li2CO3 as a source of excess lithium. By systematically investigating the effects of Li2CO3 addition during the different steps of the tape casting process and the intricate relationship between the protonation and relithiation of LLZO phase, the formation of highly protonated LLZO during ball milling was identified as the most critical step. It was shown that the addition of minimal amounts of Li2CO3 during wet milling effectively suppresses LLZO protonation and ensure the effectiveness of relithiation during subsequent sintering. Using this modified method, flat LLZO separators with a relative density of 95.3% were prepared in a simplified process with a significantly reduced excess lithium of only 5 mol% with respect to the stoichiometric LLZO, exhibiting an ionic conductivity of 0.18 mS cm−1 at room temperature and a critical current density of 1 mA cm−2 at 60°C for lithium stripping/plating.

Electrospraying is a technique in which a liquid jet breaks up into droplets under the influence of electrical forces. The technique is outstanding because of its high deposition efficiency and ability to achieve thin films with different surface morphologies. Nowadays, it is applied in the deposition of thin films for nanoelectronics in lithium-ion (Li-ion) batteries, fuel cells, and solar cells, where the performance of the deposited layers is determined by their morphologies. Although important in the design of thin films, a systematic way of depositing thin films with the desired surface morphologies for optimal operation is not available. In this study, a literature survey has been conducted from which key electrospray parameters have been identified and a comprehensive design schedule for thin films with different surface morphologies has been developed. The developed design schedule specifically targets inorganic salts, as the surface morphology of organic salts, particularly polymers, is subject to diverse factors such as solvent interaction and crystallization behavior. To verify the developed schedule, different thin films have been deposited on aluminum foil substrates using lithium salt precursor solutions by altering key electrospray parameters. Surface morphologies of the thin films have been characterized using scanning electron microscopy. Results show three distinct surface morphologies, porous with agglomerates, porous reticular, and dense particulate morphologies, and they agree with the predictions of the developed design schedule.

We present a sustainable, inherently safe battery chemistry that is based on widely available and cheap materials, that is, iron and manganese hosted in alginate bio-material known from the food and medical industry. The resulting battery can be recycled to allow circularity. The electrodes were synthesised by the alginate caging the multi-valent metals to form a hydrogel in an aqueous environment. Characterisation includes FTIR, XPS and Mössbauer spectroscopy. The electrochemical performance of the electrodes was investigated by performing cyclic voltammetry (CV) and (dis)charge experiments. Mn and Fe ions show good co-ordination with the alginic acid with higher oxidation states demonstrating complex bonding behaviour. The non-optimised iron and manganese alginate electrodes already exhibit a cycling efficiency of 98% and 69%, respectively. This work shows that Fe and Mn atomically disperse in a bio-based host material and can act as electrodes in an aqueous battery chemistry. While demonstrated at cell level, it is furthermore explained how these materials can form the basis for a (semi-solid) flow cell.

Here we present Positron Annihilation Doppler Broadening Spectroscopy (PADBS) as a powerful method to analyse the origin and development of defect processes in porous silicon structures as a result of alloying with lithium for the use in battery anode applications. Several prepared anodes were lithiated (discharged against Li+/Li) and de-lithiated (charged) with different capacities followed by a distinct treatment procedure and an analysis using the Delft Variable Energy Positron Beam. The results presented here show that we can distinguish two different processes attributed to (1) structural changes in silicon as a result of the alloying process, and (2) the formation of defects that initiate degradation of the material. The limit at which the porous material can be used for at least the first two cycles without the occurrence of damage can thus be accurately determined by using the PADBS technique.

A novel protocol for the synthesis of perylene diimides (PDIs), by reacting perylene dianhydride (PDA) with aliphatic amines is reported. Full conversions were obtained at temperatures between 20 and 60 °C, using DBU as the base in DMF or DMSO. A "green" synthesis of PDIs, that runs at higher temperatures, was developed using K2CO3 in DMSO. The reaction sequence for the imidization process, via perylene amic acid intermediates (PAAs), has been confirmed experimentally aided by the synthesis and full characterization of stable model amic acid salts and amic esters. Kinetic studies, using absorption spectroscopy, have established that PDI formation proceeds via fast amic acid formation, followed by a slow conversion to imides. Solubility of the intermediate PAA salts is found to be low and rate-limiting. Based on this finding, quantitative PDI synthesis at room temperature was achieved by diluting the reaction mixture with water, the solvent in which PAA salts have better solubility. Thus, the otherwise harsh synthesis of PDIs has been transformed into an extremely convenient functional group tolerant and highly efficient reaction that runs at room temperature.

Conformal coating of silicon (Si) anode particles is a common strategy for improving their mechanical integrity, to mitigate battery capacity fading due to particle volume expansion, which can result in particle crumbling due to lithiation induced strain and excessive solid-electrolyte interface formation. Here, we use operando transmission electron microscopy in an open cell to show that TiO2 coatings on Si/SiO2 particles undergo thickness dependent rupture on battery cycling where thicker coatings crumble more readily than thinner (∼5 nm) coatings, which corroborates the difference in their capacities.

An Atomic Force Microscope (AFM) is combined with a special designed glovebox system and coupled to a Galvanostat/Potentiostat to allow measurements on electrochemical properties for battery research. An open cell design with electrical contacts makes it possible to reach the electrode surface with the cantilever so as to perform measurements during battery operation. A combined AFM-Scanning Electro-Chemical Microscopy (AFM-SECM) approach makes it possible to simultaneously obtain topological information and electrochemical activity. Several methods have been explored to provide the probe tip with an amount of lithium so that it can be used as an active element in a measurement. The “wet methods” that use liquid electrolyte appear to have significant drawbacks compared to dry methods, in which no electrolyte is used. Two dry methods were found to be best applicable, with one method applying metallic lithium to the tip and the second method forming an alloy with the silicon of the tip. The amount of lithium applied to the tip was measured by determining the shift of the resonance frequency which makes it possible to follow the lithiation process. A FEM-based probe model has been used to simulate this shift due to mass change. The AFM-Galvanostat/Potentiostat set-up is used to perform electrochemical measurements. Initial measurements with lithiated probes show that we are able to follow ion currents between tip and sample and perform an electrochemical impedance analysis in absence of an interfering Redox-probe. The active probe method developed in this way can be extended to techniques in which AFM measurements can be combined with mapping electrochemical processes with a spatial resolution.

Developing multifunctional polymeric binders is key to the design of energy storage technologies with value-added features. We report that a multigram-scale synthesis of perylene diimide polymer (PPDI), from a single batch via polymer analogous reaction route, yields high molecular weight polymers with suitable thermal stability and minimized solubility in electrolytes, potentially leading to improved binding affinity toward electrode particles. Further, it develops strategies for designing copolymers with virtually any desired composition via a subsequent grafting, leading to purpose-built binders. PPDI dye as both binder and electroactive additive in lithium half-cells using lithium iron phosphate exhibits good electrochemical performance.

All-solid-state Li-ion batteries promise safer electrochemical energy storage with larger volumetric and gravimetric energy densities. A major concern is the limited electrochemical stability of solid electrolytes and related detrimental electrochemical reactions, especially because of our restricted understanding. Here we demonstrate for the argyrodite, garnet and NASICON type solid electrolytes, that the favourable decomposition pathway is indirect rather than direct, via (de)lithiated states of the solid electrolyte, into the thermodynamically stable decomposition products. The consequence is that the electrochemical stability window of the solid electrolyte is significantly larger than predicted for direct decomposition, rationalizing the observed stability window. The observed argyrodite metastable (de)lithiated solid electrolyte phases contribute to the (ir)reversible cycling capacity of all-solid-state batteries, in addition to the contribution of the decomposition products, comprehensively explaining solid electrolyte redox activity. The fundamental nature of the proposed mechanism suggests this is a key aspect for solid electrolytes in general, guiding interface and material design for all-solid-state batteries.

X-ray absorption and small-angle x-ray scattering spectra were simultaneously acquired under operando condi-tions in a joined technique approach, for the first time applied in the field of energy storage materials. This approach allows one to closely follow the electronic and local structure evolution, as well as monitor and quantify the morphological and nanostructural changes occurring during electrochemical cycling. Here we demonstrate its potential on the example of doped and non-doped Fe2O3 anode material vs. Li. Our results reveal that upon discharge Fe3+ is gradually reduced to the metallic state and segregated as nanoparticles. For the relithiation reaction, upon subsequent charge, we observe improved reversibility for the Sr-doped compared to non-doped and Ca-doped Fe2O3. We highlight that this combined technique approach is a reliable, facile and powerful tool to investigate electrode materials under realistic cycling condition. It provides an unbiased and holistic picture of the morphological and structural changes occurring during operation, which allows for adequate material tailoring.

With operando transmission electron microscopy visualizing solid-solid electrode-electrolyte interface of silicon active particles and lithium oxide solid electrolyte as a model system, we show tha...

High-fidelity and facile ex situ transmission electron microscopy (TEM) characterization of lithium-oxygen (Li-O-2 ) batteries is still limited by challenges in preserving the native environment of Li-O-2 discharge products. The extreme reactivity and moisture sensitivity of the discharge products means that they are quickly altered during sample retrieval from cycled batteries and transfer for TEM analysis, resulting in loss of original information. We here demonstrate that by using a TEM specimen grid directly in Li-O-2 batteries as both support electrode and sample collector overlaid on a standard oxygen diffusion electrode, discharge products that are formed on the grid can be kept pristine.

To this day, elucidating the charge transfer process in electrode materials upon electrochemical cycling remains a challenge, primarily due to the complexity of chemical reactions at the electrode surfaces. Here, we present an elegant and reliable method to probe bulk-sensitive soft edges for elucidating anodic and cathodic charge compensation contribution via X-ray Raman scattering spectroscopy. By using a hard X-ray incident beam, this technique circumvents surface limitations and is practically free of self-absorption due to its nonresonant nature. In addition, it does not require complex sample preparation or experimental setups, making it an ideal tool for potential in situ analysis of the electronic structure of electrode materials. In this study, we monitored, for the first time, bulk soft edges of both oxygen and transition metal (iron) of the cathode material Li2FeSiO4 during one complete electrochemical cycle concurrently. Our results reveal that the redox mechanism relies primarily on the iron (cathodic) contribution. Nevertheless, a change in electron confinement of the oxygen suggests its active involvement in the charge compensation process (anodic). Moreover, we were able to support the experimentally observed changes in the electronic structure with ab initio-based simulation.

The high Li-ion conductivity of the Li7P3S11 sulfide-based solid electrolyte makes it a promising candidate for all-solid-state lithium batteries. The Li-ion transport over electrode-electrolyte and electrolyte-electrolyte interfaces, vital for the performance of solid-state batteries, is investigated by impedance spectroscopy and solid-state NMR experiments. An all-solid-state Li-ion battery is assembled with the Li7P3S11 electrolyte, nano-Li2S cathode and Li-In foil anode, showing a relatively large initial discharge capacity of 1139.5 mAh/g at a current density of 0.064 mA/cm(2) retaining 850.0 mAh/g after 30 cycles. Electrochemical impedance spectroscopy suggests that the decrease in capacity over cycling is due to the increased interfacial resistance between the electrode and the electrolyte. 1D exchange Li-7 NMR quantifies the interfacial Li-ion transport between the uncycled electrode and the electrolyte, resulting in a diffusion coefficient of 1.70(3)x10(-14) cm(2)/s at 333K and an energy barrier of 0.132 eV for the Li-ion transport between Li2S cathode and Li7P3S11 electrolyte. This indicates that the barrier for Li-ion transport over the electrode-electrolyte interface is small. However, the small diffusion coefficient for Li-ion diffusion between the Li 2 S and the Li7P3S11 suggests that these contact interfaces between electrode and electrolyte are relatively scarce, challenging the performance of these solid-state batteries. (C) 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.