Negative Material Research Articles

Avoiding positivity at a cost: Evidence of reward devaluation in the novel valence selection task.

Reward devaluation theory (RDT) posits that some depressed individuals may not only be biased toward negative material but also actively avoid positive material (i.e., devaluing reward). Although there are intuitive, everyday life consequences for individuals who "devalue reward" or positivity, prior work has not established if (and how) reward devaluation manifests in tasks that encompass aspects of our daily lives, such as reading. The current research thus assessed if devaluation presents in a novel Valence Selection Task, akin to a reading assignment. In three studies, participants read incomplete reading prompts and were instructed to choose between a positively valenced, negatively valenced, or neutral sentence ending-all of which were viable sentence endings. Study 1 demonstrated that participants exhibiting depressive symptoms (assessed via fear of happiness) were less likely to select the positive endings, in line with RDT predictions. Study 2 replicated these findings, regardless of who the "subject" of the reading prompt was (self vs. other). Finally, results from Study 3 suggest that participants who displayed depressive symptoms were less likely to choose the positively valenced response, even when it was manipulated to be the objectively correct answer. These findings underscore the relevance of RDT in novel contexts and highlight potential clinical and educational applications. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Synthesis and phase purity of the negative thermal expansion material ZrV2O7

Synthesis of pure, homogeneous, and reproducible materials is key for the comprehensive understanding, design, and tailoring of material properties. In this study, we focus on the synthesis of ZrV2O7, a...

Tracking anharmonic oscillations in the structure of β-1,3-diacetylpyrene.

A recently discovered β polymorph of 1,3-diacetylpyrene has turned out to be a prominent negative thermal expansion material, with a linear thermal expansion coefficient of -199 (6) MK-1 at room temperature. Its unique properties can be linked to anharmonic oscillations in the crystal structure that can be attributed to several weak C-H...O interactions. The onset and development of anharmonic effects have been successfully tracked over a wide (90-390 K) temperature range using single-crystal X-ray diffraction. Experimental data of sufficient quality combined with Hirshfeld atom refinement of the crystal structures enabled a quantitative analysis of elusive anharmonic effects within the Gram-Charlier formalism. This example highlights that quantum crystallography tools can and should be applied in structural analysis even for data collected at high temperatures as well as of standard (∼0.8 Å) resolution.

The Role of Carbon in Lead-Acid Batteries: Applications, Challenges, and Future Opportunities

The incorporation of various forms of elemental carbon into lead-acid batteries has the potential to significantly enhance battery performance. Carbon materials are commonly used as additives to the negative active material, particularly to improve cycle life and charge acceptance under high-rate partial state-of-charge (HRPSoC) conditions, which are prevalent in hybrid and electric vehicles. Carbon nanostructures and composite materials may also offer similar benefits. However, the impact of carbon on the positive active material is generally more limited compared to its influence on the negative side. Additionally, carbon can serve as a mesh current collector for both negative and positive plates. This advanced technology boosts energy storage efficiency by increasing the battery’s specific energy and optimizing active mass utilization. Such batteries, featuring a more robust active mass structure, promise extended cycle life. Recently, another important application of carbon in secondary batteries is its use in supercapacitor electrodes, which can either replace the negative plate or be connected in parallel with the lead plate. These innovative approaches enhance overall battery efficiency by improving specific power and HRPSoC performance. Furthermore, integrating carbon-based technologies into the production of lead-acid batteries can significantly enhance their performance, giving them a competitive advantage over other battery systems. These advancements also hold substantial potential for delivering more environmentally friendly and cost-effective energy storage solutions.

Recycling Technology of Waste Lithium Batteries

Lithium-ion batteries (LIBs) are key components in new energy vehicles, portable electronic devices, energy storage systems, and other fields due to their advantages of high energy density, long cycle life, and no memory effect. However, the wide application of Li-ion batteries has also brought about a problem that cannot be ignored. The number of used lithium-ion batteries has increased dramatically. Globally, the number of lithium-ion batteries scrapped each year has reached a staggering scale, which is still growing at an alarming rate. At the same time, with the popularity of smartphones, tablet PCs, laptops, and other electronic products and the speed of replacement, the lithium-ion batteries used in these devices are also facing the problem of decommissioning and disposal. The accumulation and improper disposal of used lithium-ion batteries not only occupy a large amount of land resources, exacerbate the pressure of municipal waste disposal, but also pose a potential threat to the ecological environment. Therefore, this paper summarises the current recycling technologies of used lithium-ion batteries, mainly involving the recovery of positive and negative materials, aiming to solve the occurrence of these problems.

Thermal Enhanced Near-Infrared Upconversion Luminescence in Y2Mo4O15:Yb/Nd with Uniaxial Negative Thermal Expansion.

Thermal quenching (TQ) of luminescence presents a significant barrier to the effective use of optical thermometers in high-temperature applications. Herein, we report a novel uniaxial negative thermal expansion (NTE) phosphor, Y2-2x-2yMo4O15:xYb,yNd, synthesized by a solid-state reaction. Under 980 nm laser excitation, it exhibits excellent thermally enhanced near-infrared (NIR) upconversion luminescence (UCL) performance. The UCL intensities of Nd3+ at 573 K were enhanced by 396-fold (750 nm), 57.6-fold (810 nm), and 7.6-fold (882 nm), respectively, compared with that of room temperature. In situ temperature-dependent X-ray diffraction and steady- and transient-state spectra are used to reveal thermal expansion behavior and luminescence mechanism in detail. The thermal enhancement of NIR UCL is attributed to the synergistic effect of increased radiative transition probability due to the anisotropic thermal expansion of the crystal and the enhanced energy transfer (ET) efficiency resulting from uniaxial shrinkage and the phonon-assisted process. Based on the luminescence intensity ratio (LIR) of the thermally coupled energy levels (4F7/2/4F3/2), the target sample achieved ultrahigh sensitivity (Sr = 3.0% K-1 at 298 K) with high repeatability over the entire temperature range. This study not only provides a fresh perspective for achieving thermal enhancement of NIR UCL phosphors using uniaxial negative thermal expansion materials but also presents a novel approach for developing NIR UCL optical thermometers with outstanding temperature performance.

Міжнародний імідж України крізь призму російської інформаційної пропаганди

Abstract. This article is devoted to the definition and analysis of the main methods of Russian information propaganda and the study of their real impact on creating a negative image of Ukraine in the international community. Analysis of the foreign press showed that the Western information space is a mixture of professional research, falsifications, propaganda, open manipulation and primitive claims. It is important to note that today there is a fairly large number of foreign publications which, while supporting the Putin regime, still consider Ukraine and Russia as inseparable objects and which almost always publish negative materials about Ukraine and its people. Such sources include some information resources of Serbia, France, Turkey, etc. Western observers can obtain more objective and truthful information from official representatives of the state, diplomats, and from influential world publications that provide high-quality analytics and expert opinions. Through the websites of organizations that provide analytical and statistical materials. Also, well-known bloggers, openly declaring their political preferences and support, can shape the opinion of some people. Among the main information methods used by Russia in the fight against Ukraine are the manipulation of history and current events, the distortion of historical facts and contemporary events, the creation of a negative identity of Ukraine in the eyes of the international public, speculation on facts, the production of fake news, etc. In general, the spread of Russian propaganda about Ukraine has a negative impact on its perception in the world. And this, in turn, can create significant obstacles to the preservation and support of Ukraine's sovereignty, as well as its international integration. To combat this phenomenon, it is important to continue to strengthen international cooperation in the field of information security and to openly highlight facts and truthful information about Ukraine. Keywords: propaganda; information space; political manipulation; falsification; negative image.

A numerical simulation of a novel self-powered implantable respiration sensor based on a triboelectric nanogenerator for medical applications

Abstract The breathing rate is utilized as a reliable indicator in many cases to predict and diagnose respiratory diseases as well as the respiratory dysfunction caused by diseases such as the cystic fibrosis. Therefore, in this study, a self-powered implantable respiration sensor based on a contact-separation mode triboelectric nanogenerator (TENG) was simulated to monitor the respiratory rates by sensing the variation of the diaphragm muscle. For this purpose, a polytetrafluoroethylene (PTFE) film with a thickness of 160 μm and a nylon film with a thickness of 180 μm are employed as the negative and positive triboelectric materials, respectively. Two copper layer each with a thickness of 100 μm are placed on the outer surfaces of the triboelectric layers as the conducting electrodes. In order to uniformly deform the moving plate of the TENG, it is rigidly attached to the center of the diaphragm through a silicon mechanical coupling element with dimensions of 80 × 80 μm2. The pressure caused by breathing on the diaphragm muscle, which is in the range of 266–666 Pa, is applied to the center of the device diaphragm. The effect of various parameters including external pressure, frequency and surface charge density on the output performance of the device is also investigated. It is evident that higher external pressure results in intensive deformations of the moving plate of the TENG, leading to a more significant energy conversion efficiency of the device. Similarly, increasing the surface charge density causes an increase in all electrical output parameters. Moreover, the device achieves an output power of 0.209 nW at a load resistance of 20 GΩ by applying a constant pressure of 666 Pa at a frequency of 0.24 Hz. All the results demonstrate the potential of the new proposed sensor for detecting and monitoring real-time respiratory rates with high sensitivity and clinical applications.

Dispersion analysis of grounded dielectric slab coated with double positive (DPS) / double negative (DNG) material

The present work investigates the dispersion characteristics both for TM and TE modes in a grounded dielectric slab coated with double positive (DPS) material and double negative (DNG) material. The outermost dielectric layer is assumed to be free space. By employing proper boundary conditions at interfaces, dispersion relations for the aforementioned structure for both TM and TE modes are derived. Additionally, surface waves at the interface of free space and DPS/DNG coating are investigated. Existence of mode degeneracy for DNG/DPS combination has been discussed based on dispersion analysis.

The design of manufacturing process of mold for producing polymeric dissolving microneedles

Introduction. Polymeric dissolving microneedles are promising way for drug delivery especially for vaccine delivery. It is an important task to create a scalable way of manufacture of dissolving polymeric microneedles. First step in this process is to create an easy and cheap way of producing negative master-molds for microneedles. Objective. To develop the laser production technology of negative master-mold for dissolving polymeric microneedles. Material and methods. Possibility of using different polymer plates (polydimethylsiloxane, polycarbonate, polystyrene, polypropylene, polymethyl methacrylate and polyethylene terephthalate) for producing negative microneedle molds and material’s surface free energy were examined. The modes of laser ablation of polymer and ways of its control were investigated. Pullulan dissolving microneedles were produced by using designed molds and examined by optical microscopy. Results. Polyethylene terephthalate was chosen as the optimal polymer for producing negative microneedle mold because it leads to producing symmetrical microneedles with desired geometry. Also the 2-step laser technology for the fabrication of polymeric microneedle molds and methods of mold’s quality control during manufacture was designed in this study. The technological scheme of polyethylene terephthalate microneedle mold’s manufacture was proposed in results of this study. The variety of manufacturing defects of polyethylene terephthalate microneedle mold and it’s causes were summarized. Conclusion. The designed laser technology of producing negative microneedle molds in combination with right mold’s material (polyethylene terephthalate) can guarantee robust producing of dissolving polymeric microneedles and gives a possibility to scale it up.

Computational Imaging of Small-Amplitude Biperiodic Surfaces with Negative Index Material

Computational Imaging of Small-Amplitude Biperiodic Surfaces with Negative Index Material

Electromagnetic Simulation of a Negative Refractive Index Lens Antenna

Abstract Lens antennas are well known to achieve good multi-beam radiation patterns. When lens material is formed by a negative refractive index material, multi-beam radiation patterns are improved because the lens thickness is reduced. An electromagnetic simulator is convenient for obtaining radiation characteristics. However, the suitable electromagnetic simulator for a negative refractive index lens simulation is limited. Only a few electronic simulators can simulate a negative refractive index value. In this paper, the availability of HFSS software is examined. Calculation methods such as structure forming and calculation parameter setting are explained. Calculated results of electrical near field distribution, aperture distribution of amplitude and phase and radiation pattern are shown. By comparing calculated results with theoretical values, accuracies of calculated results are ensured.

A binder-free MnCo2O4 coated carbon cloth supercapacitor electrode with high area/gravimetric capacitance

MnCo2O4-based electrode materials with typical pseudocapacitive characteristics are ideal candidates for high energy density supercapacitors; yet high areal/gravimetric capacitances are still to be explored. Herein, we report a facile synthesis of monocrystalline MnCo2O4 on carbon cloth (MnCo2O4@CC) by a molten salt process and the mass loading can be tuned via simply changing the concentration of metal precursors. The 0.3MnCo2O4@CC sample with an optimized mass loading of 3.37 mg cm−2 shows the highest capacitance of 5.22 F cm−2/1524.6 F g−1 at 5 mA cm−2. As the concentration of precursors continuously increases, the excessive MnCo2O4 particles agglomerate and lead to reduced surface area and increased resistance, making the electrode display poorer capacitive performance. The asymmetric supercapacitor assembled by using the MnCo2O4@CC as the positive electrode and the TiO2@CC as the negative material delivers an energy density of 43.68 Wh kg−1 at 938.8 W kg−1 and a favorable value of 31.99 Wh kg−1 at a power density as high as 10.4 kW kg−1. The outstanding performance of the MnCo2O4@CC electrode and the corresponding asymmetric supercapacitor developed herein is promising for electrochemical energy storages.

Arousal and valence have dissociable effects on responses to schematic emotional faces.

Studies examining behavioural responses to emotional stimuli usually report one of two patterns of responses to negative stimuli. Some studies find faster responses to negative material. Other studies find slower responses to negative stimuli. While the attentional mechanisms proposed to explain these findings (attentional capture in the former case, delayed disengagement in the latter) are not at odds with one another, the behavioural findings do need to be reconciled. We posit that arousal, being the primary differentiator of threatening and nonthreatening stimuli, needs to be more carefully considered. To this end, two experiments were conducted evaluating the role of stimulus arousal and valence in the processing of schematic emotional faces. In Experiment 1, stimulus arousal was manipulated via the presence or absence of eyebrows in the schematic faces in a faces flanker task. Results showed faster responses to faces with eyebrows but no differences in the faces flanker asymmetry between faces with and without eyebrows. In Experiment 2, participants rated the faces on an evaluative space grid. Results showed the presence of the eyebrows had a greater impact on negative ratings for negative faces than for the other expressions. This suggests that stimulus valence and arousal were manipulated by the eyebrows and the reaction time differences could not be attributed purely to perceptual differences. Together these results suggests that both valence and arousal impact the processing of emotional schematic faces, and that these effects are dissociable. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Layered Babinet complementary patterns acting as asymmetric negative index metamaterial

Azimuthal orientation and handedness dependence of the optical responses, accompanied by asymmetric transmission and asymmetric dichroism, were demonstrated on multilayers constructed with subwavelength periodic arrays of Babinet complementary miniarrays, illuminated by linearly and circularly polarized light. In case of single-sided illumination asymmetric optical responses were observed at the spectral location of maximal cross-polarization that is accompanied by radiative electric dipoles and weak, slowly-rotating in-plane magnetic dipoles on the nano-objects; where the outgoing waves are elliptically (almost circularly) polarized. The negative index material phenomenon was demonstrated, where the electric and magnetic dipoles overlap both spatially and spectrally. The negative index material (NIM) phenomenon is accompanied by electric multipoles that add up non-radiatively and correlates with the strong, pronouncedly-tilted, rotating magnetic dipoles characteristic on the nano-entities, where the outgoing waves are linearly (slightly elliptically) polarized. By illuminating the multilayer with two counter-propagating circularly polarized beams it was proven that asymmetrical normal component displacement currents at the bounding interfaces, arising along flat and tilted bands, accompany the asymmetric copolarized and cross-polarized transmission. The latter correlates with the asymmetric dichroism in the cross-polarized signal observed in case of single-sided circularly polarized light illumination. The dispersion maps in the single-sided asymmetrical co-polarized reflectance and absorptance indicate flat bands of analogous and complementary extrema, proving the partially dichroic nature of the observed asymmetric phenomena. The Tellegen (chirality) coefficients exhibit a maximum in a spectral region coincident with the asymmetric transmission (maximal polarization rotation in the 90° azimuthal orientation). The multilayer is proposed as an ultrathin NIM and nonreciprocal nanophotonic element.

Experimental study on the effect of heating position on thermal runaway behavior of semi-solid Li-ion batteries

This study systematically explores the impact of heating position on the thermal runaway (TR) characteristics of large-format semi-solid Li-ion batteries (LIBs). Three different heating positions: the positive end, negative end, and the middle of the battery, heated with the same power, are concerned herein. The investigation encompasses TR characteristic, including temperature, venting, voltage, mass change, and the internal thermal runaway propagation (TRP) mechanism. The results indicate that there are variations in the degree of TR triggered by different heating positions. With the same heating power, overheating on the positive end led to TR in the entire battery, while overheating on the negative end caused partial TR. When the battery was heated in the middle, its surface temperature did not show a sharp increase, and only venting occurred. Specifically, positive end heating yielded a higher temperature rate of 38.25 °C/s compared to other heating positions. Voltage attenuation also differs depending on the heating position, with positive end heating, negative end heating, and middle heating processes showing voltage drops of 3.25 V, 0.1 V, and 0 V, respectively. These observations are attributed to the disparate heat dissipation properties of the positive and negative tab materials. Finally, this study elucidates the internal TRP mechanism within large-format batteries through the lens of internal heat transfer scenarios and quantitatively assesses the role of heating position in influencing TR.

Intercalation of Solvated Mg2+ into Graphite As a Negative Electrode

In the research on rechargeable Mg-ion batteries1−7 which are not limited by resource constrains, the development of negative electrode materials has been dominant on Mg metal due to its large theorical capacity per not only volume but weight. Apart from Mg metal, the reversible capacities of oxides are relatively small, despite their excellent cycling stabilities. On the other hand, althouth Sn and Sb based on alloy/dealloy reaction mechanim deliver large theoretical capacities, the large volumetric changes associated with alloying reactions with Mg disintegrate the electrodes. Meanwhile, little importance has been paid to graphite which has been used as a negative electrode material for Li-ion batteries. Mg ions are less likely to intercalate into the interlayer alone. The strong Lewis acidity hinders desolvation of the solvent molecules arround Mg ions, and thereby results in obstacles for the formation of a binary Mg-graphite intercalation compound (GIC), unlike Li-GIC. In this study, we reconsider the potential of graphite as a host material for Mg ions, including in view from ternary graphite interlayer compounds (t-GICs).8 Because the overpotential of deposition/stripping of Mg metal is relatively high, the active material could not be properly evaluated in electrochemical tests using a two-electrode cell, depending on the electrolyte used, and the potential of graphite as a negative material might have been overlooked. First, the structural changes in graphite during the application of reductive currents were evaluated by using ex-situ XRD. The electrolyte used in this study is 0.5 M Mg(TFSA)2/DMF. The formation of ternary graphite interlayer compounds (GICs) with a stage structure was demonstrated by the continual application of a constant current without considering the cut-off voltage to eliminate the influence of the counter Mg electrode. Considering the extended distance between interlayers (ca. 11 Å), the intercalated species were not Mg2+ alone but solvated Mg2+/[Mg(DMF) x ]2+ (Figure 1a). The GICs formed at the charge state turned blue tint just like the GICs synthesized by a vapor method. Galvanostatic charge/discharge tests with a current density of 7.44 mA g–1 showed a reversible capacity of approximately 200 mA h g–1 (Figure 1b). Although the challenge of large polarization during deintercalation of solvated Mg2+ has remained, the result expands the potential of graphite as a negative electrode material for rechargeable Mg-ion batteries.AcknowledgementThis work was supported by a Grant-in-Aid for Scientific Research (B) (20H02840) from the Japan Society for the Promotion of Science (JSPS).References J.-M. Tarascon, M. Armand, Nature, 414 (2001) 359.D. Aurbach, Z. Lu, A. Schechter, Y. Gofe, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich, E. Levi, Nature, 407 (2000) 724.H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci., 6 (2013) 2265.J. Muldoon, C. B. Bucur and T. Gregory, Chem. Rev., 2014, 114, 11683–11720.Y. Orikasa, T. Masese, Y. Koyama, T. Mori, M. Hattori, K. Yamamoto, T. Okado, Z. D. Huang, T. Minato, C. Tassel, J. Kim, Y. Kobayashi, T. Abe, H. Kageyama, Y. Uchimoto, Sci. Rep., 4 (2014) 5622.R. Mohtadi, M. Matsui, T. S. Arthur, S. J. Hwang, Angew. Chem. Int. Ed., 51 (2012) 9780.T. Mandai, M. Watanabe, J. Mater. Chem. A, 11 (2023) 9755.M. Shimizu, A. Nakahigashi, S. Arai, Phys. Chem. Chem. Phys., 23 (2021) 16981. Figure 1

Development of Localized High-Concentration Electrolytes Containing DME Solvent for Long-Life and High-Power Lithium-Ion Batteries

1.IntroductionWe are promoting electrification towards carbon neutrality, since the evolution of batteries is indispensable, we are developing high energy, high power and long-life lithium-ion batteries.While Ni-rich layered cathodes such as NCM811 have high capacity, the cycle life using NCM811 at high temperatures decrease. To overcome poor cycle performance, reported localized high concentration electrolytes (LHCE) which contains DMC solvent [1] was adapted to our chemical system and evaluated. Although better cycle performance at high temperature was observed, the resistance of cells using the LHCE should be lowered toward practical application.In this study, the types and concentrations of solvents were investigated for long-life and high-power battery. 2.ExperimentalThe LiFSI salt concentration was set to 1.7 mol/L, and mixtures was prepared using 1,2-Dimethoxyethane (DME) and Ethylene carbonate (EC) as solvents, and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) as a diluent as shown in Figure 1 by weight ratio of solvents.350mAh-class laminate cells were fabricated with NCM811 as the positive electrode active material and a mixture of silicon oxide and graphite as the negative electrode active material. The electrolyte amount was set to 11g/Ah. Resistance measurements were performed at 25°C with a SOC of 50%, applying a 10-second pulse from 0.2 to 2.5C for six points. Cycle tests were carried out at 60°C, charging at 0.3 C rate discharging at 0.8 C rate with cut-off voltage of 3.0-4.15 V.３. Results and DiscussionThe area specific DCR (ASD) and the absolute value of the slope of the capacity retention against the cumulative discharge energy were illustrated on the ternary diagram shown in Figure 2. The weight of EC to 15-20wt.% reduced ASD, and favorable cycle performances were obtained with a weight of TTE at 55wt.% or higher. By optimizing the electrolyte composition using DME, high-temperature cycle performance was improved by 3% and ASD resistance was reduced by 15% compared with reported LHCE using DMC which was shown as “ref” in Figure 2.The effects of electrolyte compositions and the mechanisms for improving performance will be discussed based on data such as initial charging curves, energy levels of Li-FSI state by DFT calculation, coordination number of Li-FSI by molecular dynamics simulation.*Since there was the potential risk of the corrosion on an aluminum current collector with our LHCE, investigations were conducted, and results were reported by our colleague.

Electrochemical Properties of Lif-Coated Graphite Negative Electrode Modelized By Atomic Layer Deposition

Introduction In recent years, carbon dioxide emissions are rapidly increasing, and electric vehicles (EVs) are expected to play a significant role towards achieving a carbon-neutral society with most of them utilizing Lithium-Ion Batteries (LIBs). The negative electrode active material of LIB is typically made of graphite, and during initial charging, the electrolyte undergoes reductive decomposition at the graphite/electrolyte interface, forming a Solid-Electrolyte Interphase (SEI). SEI exhibits lithium-ion conductivity while being electronically insulating, facilitating highly efficient charging and discharging by suppressing further electrolyte decomposition. On the other hand, the formation of SEI consumes lithium ions, resulting in irreversible capacity loss[1]. Therefore, the nature of SEI has a significant impact on LIB performance. Regarding the composition of SEI, it is known to comprise clusters of inorganic compounds such as LiF, Li2CO3, Li2O and organic decomposition products like polyolefins. Each component has different properties such as LiF was reported to have lower lithium-ion diffusion barrier and higher chemical stability than other inorganic components[2]. However, many aspects of the individual electrochemical roles are still unclear, and forming an excellent SEI is an important issue. Objective In this work, we focused on LiF, which is considered to be a crucial component in SEI[3], and modelized the LiF-coated graphite by employing atomic layer deposition (ALD) on highly oriented pyrolytic graphite (HOPG). We investigated the influence of LiF on the lithium-ion transfer reaction behavior at the graphite/electrolyte interface. Experimental Highly oriented pyrolytic graphite (HOPG) served as the graphite negative electrode, and atomic layer deposition (ALD) was used for the LiF coating. Regarding ALD, LiN(Si(CH3)3)2 and WF6 were used as the Li and F sources, respectively. The deposition temperature was set at 300 °C, and HOPG was deposited at various numbers of cycles (10, 30, 60, and 90 times). X-ray photoelectron spectroscopy (XPS) was performed to analyze the electrode after the ALD coating. Regarding electrochemical measurements, the setup utilized a three-electrode cell with HOPG as the working electrode, lithium metal as the counter and the reference electrodes. 1.0 mol dm−3 LiClO4/EC+DEC (1:1 vol.%) was used as the electrolyte. Cyclic voltammetry (CV) was performed at a scanning rate of 0.1 mV s−1 and a scanning range of 0.005 – 3 V (vs Li+/Li). Electrochemical impedance spectroscopy (EIS) was performed at an applied AC voltage of 5 mV and a frequency range of 100 kHz – 10 mHz. EIS measurement was also performed at different temperature with a holding potential of 0.2 V to obtain activation energy. Results and discussion For the HOPG electrode coated with LiF, XPS analysis was performed and it was confirmed that the LiF coating layer was thickening as the number of coating cycle increased. In the CV measurement results, redox peaks were observed in the range of 0 – 0.6 V, confirming that the intercalation-deintercalation reaction of lithium ion was progressing. From the Nyquist plot obtained by EIS measurements, semicircles derived from SEI were observed in the high frequency region, and semicircles derived from charge transfer resistance were observed in the medium and low frequency regions. The activation energy of the charge transfer resistance was calculated by fitting the Nyquist plot (Figure 1) obtained from the temperature-dependent measurement of EIS, and revealed that the values were 54.8 kJ mol−1 for the uncoated HOPG electrode, 55.1 kJ mol−1 for 10 coatings, and 52.8 kJ mol−1 for 30 coatings, respectively, showing no significant change. On the other hand, the activation energy slightly decreased with increasing number of depositions, which was found to be 49.7 kJ mol−1 and 50.0 kJ mol−1 in the case of 60 and 90 coatings, respectively. This suggests that when the LiF coating layer reaches a certain thickness, lithium-ion charge transfer between the electrolyte and the electrode becomes easier. Details will be discussed in the conference.

Application of Reference Electrode for All-Oxide Solid-State Battery to Reveal Electrode Reactions and Degradation Mechanisms

All-solid-state batteries are attracting attention as the next generation batteries for their wide operating temperature range, high energy density and safety. Among the several types of all-solid-state batteries, all-oxide solid-state batteries (AOSSBs) have the advantage of their particular safety due to their outstanding chemical and thermal stability without a risk of generating toxic gases. However, AOSSBs have difficulty in reassembling electrodes and reference electrodes being placed, which is essential for understanding electrode reactions during cycling and degradation mechanisms, because their fabrication process needs high-temperature sintering for sufficient inter-particle contact to have robust cells. In fact, few reports have developed the AOSSB cells with a reference electrode,[1] although there are more reports of developing reference electrodes in sulfide-type solid electrolytes, which do not need sintering.[2,3,4,5] Furthermore, even when the reference electrode is inserted into the AOSSB, it is difficult to fabricate the three-electrode cells which operates under conditions as close as possible to those of the actual full cells because the reference electrode placed in between positive and negative electrodes affects the sintered state of the solid electrolyte and many of the reference electrode configurations have influence on dimensions of AOSSB full cells.Here, we have developed a new multi-layered cell system, which incorporates reference electrodes into AOSSBs and enables the operation under conditions close to those of the actual full cells. Moreover, the reference electrodes of this system are also used as temporal carrier ion sources to adjust the redox state of each electrode.The scheme of this multi-layer cell system is shown in Fig. 1. Because the reference electrodes are located on the backside of the positive and negative electrodes, the full cell configuration in the center can work in the same way as an actual full cell. Moreover, by applying the external power source between the reference electrode and positive or negative electrode, the redox state of the positive or negative electrode can be adjusted (In this case, the reference electrode works as a counter electrode.).In this study, we demonstrate this system in Na-ion battery system with Na3Ti2(PO4)3, a bipolar active material, as both positive and negative electrode active materials, Na3Zr2(SiO4)2(PO4)3 as a solid electrolyte, and Na3V2(PO4)3 as a reference electrode active material. Using these materials, the reference electrode system successfully works to show the same electrode potential of positive and negative electrodes as reported in the literature with the liquid-electrolyte cell [6]. Furthermore, we analyzed the degradation mechanism of this full cell when cycling at various temperatures. On the meeting site, the change in voltage curves upon cycling will also be presented and the dominant degradation mode in this cell is to be discussed. Acknowledgments This study is partially based on the results obtained from a project, JPNP14004, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). We thank Zyun Siroma and Hikaru Sano (National Institute of Advanced Industrial Science and Technology (AIST)) for fruitful discussions. References Jiang et al., J. Power Sources, 529, 231278 (2022).Hertle et al., J. Electrochem. Soc., 170, 040519 (2023).Ikezawa et al., Electrochem. Commun., 116, 1067 (2020).Fukunishi et al., J. Power Sources, 564, 232864 (2023).Sedlmeier et al, J. Electrochem. Soc., 170, 030536 (2023).Senguttuvan et al., J. Am. Chem. Soc., 135, 3897 (2013). Figure 1