Sodium cobaltite (NaCo2O4) is a promising layered oxide material known for its unique electrical, thermal, and optical properties. How to tune its morphology, especially at the nanometer scale, faces many challenges. This study explores the reactive molten salt synthesis method as a highly effective approach for synthesizing NaCo2O4 nanoparticles, offering precise control over its size, shape, and structural characteristics through variations in salt composition, reaction temperature, and pH. By altering the molten salt composition, we observe significant changes in ion diffusion rates, leading to variations in particle size and crystallinity. Increasing the reaction temperature enhances grain growth, resulting in larger and more well-defined particles, while lower temperatures promote finer nanostructures. Additionally, adjusting the pH of the precursor solution influences the nucleation and growth process, affecting the shape and thickness of the resulting nanoparticles. Higher pH values favor the formation of thinner, plate-like structures, whereas lower pH conditions lead to increased particle diameter and varied morphologies. This controlled synthesis approach enables the tailored design of NaCo2O4 nanomaterials for phosphor applications, where optimized morphology enhances luminescence efficiency and stability. Moreover, the ability to fine-tune particle characteristics extends the potential of NaCo2O4 in thermos-electrics and opto-electronic devices, demonstrating the versatility of the reactive molten salt synthesis method.

Power-to-X (P2X) technologies have emerged as a crucial approach for converting surplus renewable electricity into storable and usable energy. One of the most promising applications of this concept is hydrogen production via electrolysis, where excess renewable energy is used to split water into hydrogen and oxygen [1-3]. Among the most efficient technologies enabling this conversion are high-temperature solid oxide cells (SOC)—versatile systems that operate in dual modes: as solid oxide electrolysis cells (SOEC) for hydrogen production and solid oxide fuel cells (SOFCs) for converting hydrogen back into electricity [4]. This bidirectional functionality makes SOCs particularly well-suited for integrating renewable energy into the power grid, providing an efficient solution for both energy storage and electricity generation. By 2030, SOECs are expected to lead the electrolysis industry due to their high electrical efficiency, lower material costs, and ability to function as both fuel cells and electrolysis cells.Despite the afore-mentioned advantages, SOC technology currently faces significant hurdles, one of which is the limited cell/stack lifetime of around 20,000 hours. This number also highly depends on the operating conditions and dynamic load changes which, if not managed properly, will result in a reduction of service life, and safety [5]. To avoid this, health and condition monitoring of the SOCs has proved to be highly powerful tool [6]. This is because it can be used to identify different stress and aging factors in the cell which can be used for better management of the operating conditions of the SOC. The health and condition monitoring can also be used to identify when the SOC system is reaching the end of life and should be changed/serviced before the performance of the system is considerably affected. Among the most widely adapted characterization and health monitoring methods is the electrochemical-impedance-spectroscopy (EIS) which, besides hydrogen technology, is widely applied technique for characterization of many other different energy storage technologies (e.g. batteries) [7-8]. The EIS is able to non-invasively reveal different characteristics of the SOC, including the stress and aging factors via the internal impedance which is essential information for the appropriate management of the SOC system operating in both fuel/electrolyzer cell modes.In practical applications, however, the conventional EIS is not the most feasible option due to long measurement time, and the fact that it applies sinusoidal signals which are difficult to generate with low-cost electronics and hardware [8-9]. Moreover, the EIS poorly tolerates any drifting of the operating conditions within the measurements which also hinders the practical applicability of the EIS. An attractive alternative is provided by the pseudo-random sequence (PRS) perturbation signals, that are able to produce rapid measurements, and which are comprised of only a few signal levels, facilitating their practical implementation in a real-world SOC stack/system [8]. In particular, a special three-level PRS perturbation has been recently validated to be highly effective for real-time monitoring of Li-ion battery impedance under drifting operating conditions [9]. Capability to perform at drifting operating conditions can be highly beneficial for the SOCs which often experience drifting operating conditions in practice [10].This work demonstrated the use of three-level PRS perturbation for rapid and practical impedance measurements of SOC operating at fuel cell mode. The fuel cell operation is conducted at 700 °C, with a gas mixture of 1% H₂ and 20% N₂ on the fuel side and 20% air on the air side. Due to the limitations of the available laboratory equipment, only fuel cell mode was demonstrated in this study. During the measurements, the open-circuit-voltage (OCV) of the SOC has not yet stabilized after the system start-up which demonstrates an example of such dynamic (or non-steady-state) operating conditions. The three-level PRS perturbation is superimposed on a DC discharging current of 36 mA with the other two PRS signal levels corresponding 0 A and 72 mA. The measurement duration in total was two seconds and it covers a bandwidth of 2.5 Hz – 4 kHz. The results are presented in Figure 1, which shows both the measured Nyquist curve (left figure) along with the voltage and current partial data records (right figure). Small drifting of the OCV of the SOC indicates the dynamic operating conditions. Overall, the proposed method can rapidly (i.e. in two seconds) produce realistic impedance results which can be further applied to health assessment of SOC.FIGURE CAPTION: "Figure 1. Measured impedance spectrum (left). Voltage and current samples of the measurements (right)"The future work will focus on validating the PRS capability to perform also on electrolyzer mode. Moreover, the method performance under different realistic current profiles, such as those often found in electric vehicles, or in typical electrolyzer use-cases should be validated. An important part of the future studies is also to prove that the impedance data measured at dynamic operating conditions is valid and eventually applicable to health monitoring algorithms of SOC cell/stacks/systems.

Proton exchange membrane water electrolysis (PEMWE) is a promising route to produce cost-effective H2. However, thinner membranes and high cathode differential pressure are required to maximise its efficiency, and minimize cost. [1] Under such conditions, hydrogen crossover leads to undesired efficiency losses and safety hazards. Efforts to mitigate the effects of H2 crossover include the development of membranes which include a Pt recombination catalyst that consumes the H2 and thus improves the turn down ratio of the electrolyzer. Methods to quantify the rate of recombination at the different components and interfaces in PEMWE cells are necessary to assess the effectiveness of the recombination catalyst.In this contribution, we quantify the total amount of H2 harvested at the cathode, consumed in the cell, and leaving the anode compartment. By measuring the rates of hydrogen leaving both anode and cathode and comparing to Faraday’s law, we can quantify the total amount of H2 being consumed in the cell. Figure 1 shows a schematic of the different processes occurring across a cell’s cross-section, as well as the newly developed technique to quantify H2 exiting the cathode. The anode stream is measured using our previous method for analyzing the anode exhaust. [2] In this talk we will discuss results that verify the technique using a benchmark system at different cathode pressures, and apply it to membranes with and without recombination catalysts.

The tunable properties of organic molecules make them versatile materials for electrochemical applications including electrocatalysis and energy storage. However, each application demands tailored molecular design with specific critical properties. In the context of redox catalysis, it is necessary for redox shuttles to exhibit rapid heterogeneous and homogeneous electron transfer rates; however, the relationship between electron transfer rate constants and small variation in molecular structure remain poorly understood. The traditional design of organic molecules relies on iterative synthesis and property testing, based on which successive derivatives are developed until optimal performance is achieved. This approach, however, requires sequential optimization of multiple functional properties which makes it slow for practical implementation. A more effective design strategy involves establishing predictive relationships between desired physical or chemical properties and molecular structure parameters - referred to as structure-property relationships. Small strategically designed data sets for a core structure can be used to develop predictive models that enable rapid virtual screening for analogues with enhanced properties. A key advantage of this approach is their versatility as they can be applied to any quantifiable parameter of interest.In this talk, we share the application of this design strategy in the development of energy storage molecules and how this method can be adopted for streamlined redox catalyst design.

All-solid-state batteries (ASSBs) have emerged as promising next-generation energy storage systems due to their enhanced safety, enabled by replacing flammable liquid electrolytes with non-flammable solid electrolytes. However, interfacial challenges, arising from complex chemo-mechanical interactions between cathode active materials and solid electrolytes (SEs), hinder the commercialization of ASSBs. Since degradation in ASSBs is strongly influenced by the SEs used in composite cathodes, understanding SE-dependent degradation mechanisms is crucial. In this study, we investigate the degradation mechanisms of LiNi0.8Co0.1Mn0.1O2 (NCM) composite cathodes with either the sulfide-based Li6PS5Cl (LPSCl) or the halide-based Li2ZrCl6 (LZC) SEs from the initial cycle to prolonged cycling. A combination of electrochemical techniques, synchrotron X-ray-based analyses, and electron microscopy is employed. In the NCM-LPSCl cathode, capacity loss occurs primarily in the initial cycle due to interfacial side reactions, such as LPSCl oxidation and Ni reduction at the NCM surface. The reaction products, including P2S5, S, SOx, and POx species, form resistive interphases at the interface. In contrast, the chemically stable NCM-LZC cathode exhibits a higher initial capacity due to the absence of such side reactions. However, during prolonged cycling, high capacity utilization of the NCM-LZC cathode induces significant lattice strain, generating mechanical stress at the solid interface. This strain promotes the formation of voids and cracks within the composite cathode, leading to physical contact loss and continuous capacity fading. Our findings highlight distinct degradation factors in each system: resistive interphases in the NCM-LPSCl cathode, and mechanical contact loss in the NCM-LZC cathode. Further details will be discussed at the meeting. Figure 1

Title: High-Concentration Electrolytes and Ionic Liquid Formulations for Enhanced Li–O₂ Battery Performance Lithium-oxygen (Li-O2) batteries have attracted significant attention due to their potentially higher energy density compared to Li-ion batteries. However, choosing the right liquid electrolyte is critical for achieving optimal discharge-charge capacity and cycle life. The electrolyte must remain stable against decomposition at higher voltages and help form robust solid electrolyte interfaces (SEI) and cathode electrolyte interfaces (CEI).In this work, we examine two glyme-based solvate ionic liquids (SILs) triglyme and tetraglyme, each mixed in an equimolar ratio with LiTFSI salt (Li(G3)TFSI and Li(G4)TFSI, respectively). We also analyze a highly concentrated dimethyl sulfoxide (DMSO) electrolyte with a 3:1 molar ratio. Because these electrolytes have high viscosity and relatively low ionic conductivity, we investigate how temperature affects them. Elevated temperatures have a more pronounced effect on improving the oxygen reduction (ORR) and oxygen evolution (OER) reactions in these highly concentrated electrolytes (HCEs) compared to low-concentration electrolytes (LCEs).Another approach to lower viscosity and increase ionic conductivity in HCEs is to use non-solvating diluents (known as locally high concentration electrolytes, LHCEs) that do not dissolve the LiTFSI salt. However, many of these diluents are more volatile than the common solvents (DMSO, TEGDME) used in Li-O2 batteries. We explore which of the three HCEs performs best when diluted with a non-coordinating cosolvent at room temperature.Finally, we investigate the effect of a ternary mixture of ionic liquids (ILs) with DMSO. Imidazolium-based ILs exhibit higher oxidative stability, oxygen solubility, and diffusivity than organic electrolytes, whereas pyrrolidinium-based ILs display better stability with the lithium anode. Therefore, we investigate the mixture formulation of these two types of ILs with DMSO as organic electrolytes to develop an electrolyte with lower volatility and greater stability than pure DMSO.To evaluate the performance of these electrolytes, we assess the average overpotential, deep discharge-charge capacity, cycling stability, and resistance to electrolyte decomposition in Li-O2 batteries. Moreover, we study the interaction of these electrolytes with the lithium anode by using SEM to observe SEI morphology and X-ray photoelectron spectroscopy (XPS) to identify the SEI’s chemical components. In addition, we examine the distribution and morphology of the solid discharge products at various temperatures within the positive electrode.

Developing new and safe electrolyte formulations is a major challenge for the adoption of higher energy electrode chemistries in electrochemical energy storage devices. Electrolyte engineering must balance performance, affordability, and safety in new formulations. There are hundreds of possible solvents, salts and additives to tailor the electrolyte to the right application. Computational tools are a promising solution to accelerate the process through machine learning,1 thermodynamic calculations,2 and molecular dynamics.3 These techniques can be computationally expensive and, without a substantial training set, still require extensive experimental validation of their results. Experimental electrolyte dataset availability is still limited due to the absence of standardization in the field, and it is challenging to scrape the literature. Therefore, there is a need for experimental tools to generate new electrolyte datasets for powerful data analysis techniques to enable novel battery chemistries.In this presentation I will discuss our automated system for electrolyte formulation and characterization in the context of aqueous electrolyte discovery. The platform autonomously handles electrolyte components and conducts electrochemical tests including Coulombic efficiency, cyclic voltammetry and impedance spectroscopy. Here we screen possible combinations of widely used aqueous electrolyte salts including lithium acetate, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethane)sulfonimide (LiTFSI), lithium nitrate, and lithium sulfate . The chosen salts contain anions spanning a wide range of the Hofmeister series, which classifies them between chaotropic (structure breaking) and kosmotropic (structure making). It has been shown that chaotropic anions expand the Electrochemical Stability Window (ESW), specifically, increasing the potential at which OER occurs, though there is still a debate in the literature about the true impact of anions on the stability window.4,5 Moreover, enabling aqueous electrolytes depends on enabling high energy anodes. Currently, various +3 V lithium aqueous battery chemistries rely on using high concentrations of LiTFSI. Here we outline possible strategies to enable higher energy anodes such as lithium titanate while constraining our material use. We leverage our high-throughput electrolyte characterization platform to produce high quality, consistent, open-source databases of electrolyte properties that we envision will assist and accelerate the entire field’s research. Our long-term goal is to go beyond aqueous electrolytes and to use the comprehensive data generated to make fundamental advances in developing new electrolyte models that will allow researchers to quickly predict optimal formulations and device performance.1 S. C. Kim et al., Proceedings of the National Academy of Sciences, 120, e2214357120 (2023).2 A. Dave, K. L. Gering, J. M. Mitchell, J. Whitacre, and V. Viswanathan, J. Electrochem. Soc., 167, 013514 (2019).3 B. Ravikumar, M. Mynam, and B. Rai, J. Phys. Chem. C, 122, 8173–8181 (2018).4 D. Reber, R. Grissa, M. Becker, R.-S. Kühnel, and C. Battaglia, Advanced Energy Materials, 11, 2002913 (2021).5 D. Dong, C.-X. Zhao, X. Zhang, and C. Wang, Advanced Materials, n/a, 2418700.

Soy wax (SW)/banana peel-derived carbon (BDC) composite phase change materials (PCMs) were fabricated by vacuum impregnation, where three types of BDC (BDC-1, BDC-2, and BDC-3) as carrier were synthesized by activation via carbonization process. The BDC modified by KOH-assisted calcination process had a highly porous structure with considerably higher inner surface area (over 1000 m2 g-1) where the weight ratio of BDC to KOH was 1:3 than other matrixes, leading to that a maximum loading capability value of SW in SW/BDC-3 composite. X-ray diffraction and Fourier transform infrared spectroscopy shown that physical interaction instead of chemical reaction happened between BDC and SW. X-ray photoelectron spectroscopy indicated that KOH-assisted calcination treatment improved oxygenic functional groups on matrix surface so that facilitating activation of banana peel and SW loading. Raman spectra illustrated the IG/ID value of three amorphous carbons were monotonously decreased by increasing weight ratio of BDC to KOH. The thermal conductivity was significantly higher than pure SW. For SW/BDC-3 composite, it had a minimum melting temperature but had a maximum enthalpy and phase transition point at approximately 50oC. It was also stable in terms of thermal and chemical after thermal cycles in heating and cooling. Thus, the SW/BDC-3 exhibited high phase transition enthalpy and excellent thermal stability has potential application in thermal energy storage.

Hydrogen peroxide is a little explored oxidant for the deposition of silicon dioxide or silicon oxycarbide films. In this work, we discuss the atomic layer deposition of SiO2 and SiOC films using a variety of hydrogen peroxide sources, demonstrating the critical impact of water on the growth rate and properties of the resulting silicon-containing films. It will be shown that with the correct choice of hydrogen peroxide source and silicon precursor, SiO2 and SiOC films can be grown at ambient temperatures in a thermal ALD process . Furthermore, the low temperatures and specific oxidation conditions of these processes afford ample opportunity for selective growth on a variety of substrate combinations, such as dielectric-on-dielectric, dielectric-on-metal, and dielectric-on-semiconductor. Plasma-based and thermal densification of the resulting films will also be discussed, as will deposition of SiO2 on oxidatively or temperature sensitive substrates such as polymer films and pharmaceutical compounds.

The growing demand for electric vehicles, as well as the need for viable grid storage batteries, has initiated a world-wide search for materials that can further enable these technologies. In this regard, the development of cost-effective, and energy efficient lithium-ion battery cathodes is of critical importance. Currently, Ni-rich NMC oxides (LiNi x Mn y Co z O2, x+y+z = 1) are the most advanced, high-performance materials for use as Li-ion cathodes. However, increasing concerns over sustainability, supply chain issues, and cost-effectiveness of critical elements like Co and Ni have accelerated the need for more earth-abundant options such as those based in Mn.1 Lithium and manganese rich cathode materials (LMRs), with general formula xLi2MnO3 • (1-x)LiMO2, can achieve high energy densities, and thus represent attractive alternatives.2-3 However, there are several materials barriers, both bulk and surface related, that prevent Mn-rich cathodes from being implemented on a wider scale in commercial cells. At the bulk level, an anomalously-high area specific impedance (ASI) occurs at low states of charge (SOCs) that has, until recently, been largely overlooked.4 At the surface level, preventing the dissolution of Mn remains a significant challenge.In this work, we will discuss a strategy based on ‘domain-specific’ substitutions5 to address the problem of high ASI at low SOCs. Furthermore, we will present a surface modification6, based in atomic layer deposition (ALD) – in contrast to typical wet-chemical routes – that shows considerable promise towards mitigation of Mn dissolution, greatly extending the cycle life of cells utilizing Mn-rich cathodes.