Microstructure, Charge Transport and Interfaces in All-Solid-State Batteries

Due to their potentially higher energy densities and advantages in safety, all solid-state batteries (ASSBs) are being considered to replace conventional Li-ion batteries in a number of applications. Ceramic garnet-type electrolytes are promising candidates for the solid electrolyte in ASSBs because they provide high ionic conductivity and a wide electrochemical stability window.To improve battery performance, the optimization of the composite cathode in ASSBs is crucial. The microstructure of the cathode as well as interface phenomena occurring between active material particles and electrolyte grains are performance-limiting factors which need to be improved.In our contribution, we present microstructure resolved simulations in the 3D simulation framework BEST [1] demonstrating the effects of characteristic properties of the microstructure on the cell performance. By simulation studies using composite cathode microstructures with different particle size, active material fraction, and sinter density, we are able to identify advantageous properties which can serve as a target for the cell production.In the experiments, a large polarization of garnet-based ASSBs is observed which is commonly attributed to secondary phase formation between the active material and electrolyte in the production process [2]. Therefore, a new electrochemical interface model is introduced to account for the hindered transport of Li and electrons due to secondary phases. This model is based on physical parameters of the interface and, thus, can be used to get insights into the interface properties which are still subject of intensive research [3].[1] Latz, A.; Zausch, J. Thermodynamic consistent transport theory of Li-ion batteries. J. Power Sources 2011, 196, 3296-3302.[2] Finsterbusch, M.; Danner, T.; Tsai, C.-L.; Uhlenbruck, S.; Latz, A.; Guillon, O. High Capacity Garnet-Based All-Solid-State Lithium Batteries: Fabrication and 3D-Microstructure Resolved Modeling. ACS Applied Materials & Interfaces 2018, 10, 22329-22339.[3] Vardar, G.; Bowman, W. J.; Lu, Q.; Wang, J.; Chater, R. J.; Aguadero, A.; Seibert, R.; Terry, J.; Hunt, A.; Waluyo, I.; Fong, D. D.; Jarry, A.; Crumlin, E. J.; Hellstrom, S. L.; Chiang, Y.-M.; Yildiz, B. Structure, chemistry, and charge transfer resistance of the interface between Li7La3Zr2O12 electrolyte and LiCoO2 cathode. Chem. Mater. 2018, 30, 6259–6276.

The sulfide-based all-solid-state batteries (ASSBs) has guaranteed having excellent safety by using non-combustible inorganic solid-electrolyte (SE). SE separator can transport Li ion selectively and there is no concentration gradient in theory, enabling fast charging. In addition, due to high ionic conductivity of sulfide-based SE comparable to liquid based electrolyte, high capacity and high energy density ASSBs of 5mAh cm-2 have been developed to a stage close to commercialization.So far, among the many issues of ASSBs, the performance improvement has been achieved by focusing on interfacial deterioration issues. However, recent several studies have analyzed and identified the cause of inhomogeneous reaction in composite cathode, which lead to capacity degradation quickly. It had been confirmed that the inhomogeneous reaction was caused by not only loosely contact and isolated active materials but also restriction Li conductivity in nano-crystal boundaries of active materials, resulting in localizing overcharge-discharge and decreasing in capacity and rate capability. As one of intrinsic properties of ASSBs, the solid-solid contact induce the limitation of lithium ion mobility and it also triggered insufficient electronic conduction pathway increasing charge transfer resistance.In order to develop high-energy density and high power ASSB, the ability of the conductivity for electron and ion must be balanced through the formation of a well-developed electronic percolating pathway. In this study, the inhomogeneous reactivity that can be maximized in thick electrodes is alleviated by improving the electron transfer path in the composite cathode. To uniformly transfer electrons in the composite cathode, we introduced argyrodite type SE coating with 2D conductive material under solvent environment. This approach is effective on forming a continuous electronic pathway for homogeneous reactivity as well as reduce SE oxidation by preventing direct contact between SE and cathode active material. As a result, we obtained a high initial capacity of 206 mAh g-1 using a single LiNi0.8Co0.1Mn0.1O2 cathode and SE coated with 2D conductive material, and confirmed that approximately 90% rapacity maintained after 200th cycle.

All-solid-state batteries (ASSBs) using inorganic solid electrolytes are expected to achieve high safety and high energy density as alternatives to conventional lithium-ion batteries using liquid electrolytes. However, in many cases, rate capability of ASSBs is poor compared with that of the conventional liquid system. This is because the contact interface between solid active materials and solid electrolyte is insufficient, resulting in high resistance for electrochemical properties. The solid electrode-electrolyte interface in ASSBs is related to the morphological structure such as porosity and mixed state. It has been confirmed that pressurization reduces the grain boundaries of solid electrolytes and improves conductivity1). From this improvement, it is generally known that applying high pressure when assembling ASSBs improves the contact area of the solid-solid interface, including electrode and electrolyte interface. However, the effect of pressure on particle-particle contact and battery performance is not understood enough. In this study, we investigated the effect of pressure-induced three-dimensional structure on the electrochemical properties of ASSBs by using X-ray computed tomography (CT). ASSBs were prepared at various stack pressures using a composite cathode consisting of oxide active materials LiNi1/3Co1/3Mn1/3O2 (NCM), sulfide solid electrolyte Li10GeP2S12 (LGPS), and acetylene black. Electrochemical properties were investigated in ASSBs of NCM composite cathode|LGPS solid-electrolyte|In-Li anode. The charge–discharge measurements were performed using various stack pressure, which indicates that the capacity increases as the stack pressure increases. To analyze the factors behind this result in terms of the internal structure of the ASSBs, we performed X-ray CT with synchrotron radiation at 20 keV using a homemade operando measurement cell that electrode diameter is 1 mm. This measurement system allows us to analyze the three-dimensional structure of composite cathode during monitoring applied pressure, electrochemical measurements, and X-ray CT measurements. From the X-ray CT data, we succeeded in quantifying the changes in the porosity of the composite cathode and the contact state between the active material and electrolytes by changing the pressure. Quantitative analysis revealed that the porosity and contact state correlate with the charge–discharge properties. Additionally, CT analysis revealed that the voids are preferentially presented near active materials and these voids spread the horizontal direction (not pressurization direction), resulting in different porosities of composite cathode and solid electrolyte layer. Since it was confirmed that voids remained in the vicinity of the active material even when the pressurization was continued, controlling these voids decreases the voids of the entire cathode layer. Pressure dependencies on AC impedance during X-ray CT measurements showed that the apparent conductivity of ASSBs increases linearly as the confinement stack pressure increases. This result is caused by suggesting that the decrease in porosity and tortuosity in cathode layer, which is detected by CT analysis. Additionally, date of tortuosity shows over-pressurization may bypass Lithium conduction path. The improved internal structure such as contact state due to pressurization enhances the apparent conductivity and charged-discharge characteristics of ASSBs. With the latest synchrotron radiation measurement technology and image processing technology, high-precision analysis has become possible.1) Jean-Marie Doux, Yangyuchen Yang, Darren H. S. Tan, Han Nguyen, Erik A. Wu, a Xuefeng Wang, Abhik Banerjeea and Ying Shirley Meng, J. Mater. Chem. A, 8, 5049, (2020).

Electrifying the automotive sector requires energy storage systems with high energy and power density, intrinsic safety, and long durability.[1] Lithium-based all-solid-state batteries (ASSBs) are considered promising next-generation energy storage devices, as they possibly meet these requirements by replacing organic liquid electrolytes with non-flammable solid electrolytes (SEs) and by enabling the application of novel high energy density anode concepts.[2, 3] Among the SE material classes being pursued for use in ASSBs, sulfidic systems are considered particularly advantageous, as they possess high ionic conductivities and low Young’s moduli, enabling easier processing and densification compared to oxidic systems.[4] However, a rarely addressed key bottleneck to commercializing ASSBs with sulfidic SEs is the requirement on the environmental conditions during handling, processing, and assembly of the battery components, which will be dictated by the instability of sulfidic SEs towards humidity.[5] On the laboratory scale, this issue has been avoided by handling the sulfidic ASSB materials, components, and cells in argon-filled gloveboxes, but for the commercial production of ASSBs their manufacturing would preferably be done in a dry-room atmosphere.[6] However, very few studies exist that examine whether the dew points of typical dry-rooms are sufficient to handle and/or store ASSB components based on sulfidic SEs.[7,8] In this contribution, we will examine the dry-room compatibility of scalable sulfidic composite (Li6PS5Cl/HNBR) sheet-type separators,[9] investigating the influence of the exposure time to a dry-room atmosphere with a dew point of -48°C on the stability of the SE and on its electrochemical properties. Using X-ray diffraction (XRD) combined with Rietveld refinement and scanning electron microscopy (SEM), the influence on the morphology and the formation of degradation products upon reaction with the small concentration of water in a dry-room will be investigated. The results show that only long exposure times (> 96 h) lead to a significant hydrolysis-induced change in the XRD diffractograms, which indicates the formation of degradation products such as Li2S, LiCl, and Li3PO4.By means of potential electrochemical impedance spectroscopy (PEIS), the impact of different exposure times on the Li+-ion conductivity of the sheet-type Li6PS5Cl/HNBR separators and the activation energy for the Li+-ion transport are investigated (cf. figure 1). While short exposure times (< 12 h) have a minor influence on the Li+-ion conductivity (lowering it from 0.3 mS/cm to 0.25 mS/cm) and a negligible effect on the activation energy, longer exposure times (> 48 h) lead to a ≈ 10-fold loss of ionic conductivity (to ≈ 0.03 mS/cm) and a drastic increase in activation energy.Besides measuring the loss of ionic conductivity, the separator sheets are also used for assembling LiNi0.6Co0.2Mn0.2O2|LiIn half-cells, which are investigated using galvanostatic cycling. An analysis of the capacity profiles shows that an increased exposure of the separators to the dry-room atmosphere leads to a significant IR-drop, to lower initial discharge capacity, and enhanced capacity fading over several charge/discharge cycles. Further insights into these degradation phenomena will be gained by analyzing the dQ/dV plots, the mean (dis)charge voltage, and the full-cell impedance of the half-cells.Based on our findings, it can be concluded that moderate exposure times in a dry-room of up to 12 h have only a negligible effect on the chemical integrity and performance of sulfidic Li6PS5Cl/HNBR separators sheets. This opens the route of defining viable storage and processing times of sulfidic ASSBs cell components in industrial dry-room environments.[1] Y. Ding, Z. P. Cano, A. Yu, J. Lu, Z. Chen, Electrochemical Energy Reviews, 2, 1 – 28, (2019).[2] J. Janek and W. G. Zeier, Nature Energy, 1, 16141, (2016).[3] P. Oh, J. Yun, J. H. Choi, K. S. Saqib, T. J. Embleton, S. Park, C. Lee, J. Ali, K. Ko, J. Cho, Angew. Chem. Int. Ed., 61, e202201249, (2022).[4] A. Sakuda, A. Hayashi, M. Tatsumisago, Scientific Reports, 3, 2261, (2013).[5] H. Muramatsu, A. Hayashi, T. Ohtomo, S. Hama, M. Tatsumisago, Solid State Ionics, 182, 116 – 119, (2011).[6] D. H. S. Tan, Y. S. Meng, J. Jang, Joule, 6, 1755-1769, (2022).[7] Y.-T. Chen, M. A. T. Marple, D. H. S. Tan, S.-Y. Ham, B. Sayahpour, W.-K. Li, H. Yang, J. B. Lee, H. J. Hah, E. A. Wu, J.M. Doux, J. Jang, P. Ridley, A. Cronk, G. Deysher, Z. Chen, Y. S. Meng, J. Mater. Chem. A , 10, 7155-7164, (2022).[8] C. Singer, H.-C. Töpper, T. Kutsch, R. Schuster, R. Koerver, R. Daub, ACS Appl. Mater. Interfaces, 14, 24245–24254, (2022).[9] C. Sedlmeier, T. Kutsch, R. Schuster, L. Hartmann, R. Bublitz, M. Tominac, M. Bohn, H. A. Gasteiger, J. Electrochem. Soc., 169, 070508, (2022). Figure 1

All-solid-state batteries (ASSBs) are expected to have less safety concern than Lithium-ion batteries with organic liquid electrolyte (LIBs) because flammable liquid electrolytes are not used in ASSBs. The thermal behaviors in LIBs have widely discussed in many literatures1. However, thermal behaviors of ASSBs have not investigated much.In this study, to clarify the self-heating phenomenon of our prototype ASSB with Argyrodite-type solid electrolyte we have performed calorimetric studies and gas analyses. In the calorimetric measurement, an accelerated rate calorimetry (ARC) was used to compare the starting temperature of self-heating in ASSB to that in LIB. It was found that the self-heating of ASSB takes place at 200-300ºC which was significantly higher than that in LIB.To identify the endothermic and exothermic peaks in the calorimetric profile and to estimate the amount of heat generation in ASSB, a Calvet-type calorimeter (C600) and a differential scanning calorimeter (DSC) were used with a heating rate of 1 ℃/min under Ar atmosphere for a full cell and electrode layers of the ASSB, respectively. The exothermic peaks at 200- 300℃ for charged ASSB (at ca. 4.1 V) mostly corresponded to those for the cathode layer which was extracted from the charged ASSB. The crystal structure change of the cathode layer charged at ca. 4.1 V associated with temperature change was analyzed by X-ray diffraction (XRD) to understand the reaction mechanism. The XRD peaks for the active material and the solid electrolyte in the cathode layer were disappeared at 200-300ºC. It was suggested that the heat generation at 200- 300ºC were mainly caused by the reaction between the cathode active material and the solid electrolyte.We also analyzed the evolved gas during the heating of ASSB using a temperature-programmed desorption-mass spectrometry (TPD-MS). The detailed mechanism will be discussed on-site.AcknowledgmentsThis study was carried out in SOLiD-EV project supported by NEDO (New Energy and Industrial Technology Development Organization).References Xuning Feng, Minggao Ouyang, Xiang Liu, Languang Lu, Yong Xi, Xiangming He, Energy Storage Materials 10 (2018) 246-267.

For the growth of electric vehicle market, lithium-ion batteries (LIBS) used in the EVs still requires safety and reliability. Unfortunately, large-scale application of the LIBs is being challenged due to the fact that the use of flammable liquid electrolytes has caused safety issues such as leakage and fire explosion. In this respect, all-solid-state batteries (ASSBs) have been intensively studied to ensure the safety and mileage that are superior to the current LIBs. In terms of solid electrolytes, oxide electrolytes not only shows high ionic conductivity (10-4 ~ 10-3 S/cm) but also high mechanical strength to suppress surface dendrite formation. In addition, the oxide electrolytes possess advantages such as non-flammability, high thermal stability, and excellent electrochemical stability (~ 6 V), enabling high temperature/high voltage operations of oxide-based ASSBs. However, most of oxide materials require a sintering process at high temperatures to form a planar solid electrolyte. And a lack of flexibility results in non-uniform electrolyte/electrode contact in the battery, which makes it difficult to apply the rigid oxide electrolyte directly. On the other hand, solid polymer electrolytes have also been actively investigated due to no leakage, good electrolyte/electrode contact, easy processing, flexibility, and good film formability. However, the solid polymer electrolytes have critical disadvantages such as low ionic conductivity at room temperature and low thermal/mechanical stability, which precludes commercialization of solid polymer-based ASSBs despite their advantages. To overcome each disadvantages of oxide and polymer electrolytes, we developed hybrid electrolytes for improved ionic conductivity, easy processing, and formation of continuous electrolyte/electrode interface. In this presentation, pragmatic approach and current challenges related to solid batteries will be discussed including innovative manufacturing process. Hybrid electrolytes and their synergistic effect on the battery performance as a promissing solution will be presented [Fig. 1]

Innovation in the design of Li-ion rechargeable batteries is necessary to overcome safety concerns and meet energy demands. In this regard, a new generation of Li-ion batteries (LIBs) in the form of all-solid-state batteries (ASSBs) has been developed, attracting a great deal of attention for their high-energy density and excellent mechanical-electrochemical stability. This review describes the current state of research and development on ASSB technology. To this end, study of the literature and patents as well as market analysis over the last two decades were carried out, highlighting how scientific achievements have informed the application of commercially profitable ASSBs. Analyzing the patents registered over the past 20 years revealed that the number of them had increased exponentially-from only few per year in early 2000 to more than 342 in 2020. Published literature and patents on the topic declare a solid-state electrolyte (SSE) to be the main component of ASSBs, and most patented examples are referred to as solid inorganic electrolytes (SIEs), followed by solid polymer electrolytes (SPEs) and solid hybrid electrolytes (SHEs) in popularity. Investigation of company websites, social media profiles, reports, and academic publications identified 93 companies associated with ASSBs. A list of leading businesses in the solid-state battery sector was compiled, out of which 36 provided information on the ASSB units in their product portfolio for detailed analysis.

Inorganic solid electrolytes are one of the key materials instead of organic liquid electrolytes for next-generation all-solid-state batteries (ASSBs). The advantages of ASSBs are long cycle life and high safety due to the non-flammable of the solid electrolyte. The ASSBs can be stacked layer by layer, reducing the volume in battery packaging and resulting in increased energy density. These ASSBs can be applied to wearable or healthcare or smart home devices in the form of multilayer ceramic battery (MLCB), in addition to energy storage devices and electric vehicles. However, the MLCBs are difficult to fabricate due to the high sintering temperature and high interfacial resistance of the solid electrolyte. The Li-based solid electrolytes of NASICON-type have received much attention as prospective solid electrolytes due to their high ionic conductivity and high stability against moisture. Especially, lithium aluminum germanium phosphate (LAGP) is potential solid electrolyte material in the NASICON family due to superior stability. LAGP glass electrolyte was selected to enable sintering at low temperatures and reduce resistance at the interface for the application to MLCB.In this study, a LAGP-based solid electrolyte ceramic sheet was prepared using glass/powder composite at 750 °C. The obtained LAGP-based solid electrolyte exhibited a NASICON-type hexagonal structure and a total ionic conductivity of 1.45 × 10-4 S/cm at 25 ˚C. A Coin cell with the LAGP composite electrolyte, LiCoO2 (LCO) as cathode, and Li metal as anode was assembled. The coin cell was charged and discharged by using a battery cycler and the charge capacity was approximately 130 mAh∙g-1. Additionally, we prepared a LiMnPO4 glass-based cathode (LMP) using conventional melt quenching techniques and then stacked it layer by layer with the LAGP electrolyte and co-sintered at 650°C. After co-sintering the LAGP/LMP cell, it was confirmed that the interface between the LAGP composite electrolyte and the LMP cathode was well attached, and its ionic conductivity maintained a value similar to that of the LAGP composite electrolyte. Subsequently, an electrochemical analysis of the LAGP/LMP cell was performed.

Recently, the use of liquid electrolytes in lithium batteries is prone to cause safety problems such as leakage and gas explosions. The PEO-based solid composite electrolytes (CE) for all-solid state batteries (ASSBs) have been studied for a possible replacement for liquid electrolytes. However, it results in degradation of mechanical properties and short circuit during cycling at the high temperature (60~80°C). Therefore, the thickness of electrolytes is required to be 150㎛ or more. However, to improve the energy density of all-solid state battery, it is required to reduce the thickness of the solid electrolyte layer to as low as 50㎛ and less. As a method for reducing the thickness, we suggested that the thin solid composite electrolyte film was composed of PEO/PVDF blending polymer as ionic conductor and binder including lithium salts and garnet LLZO powders. In addition, the composite cathode slurry was composed of NCM active material, Super P, Garnet-type LLZO powder and PEO/PVDF blending polymer. The electrochemical properties were measured by the AC impedance method, Linear Sweep Voltammetry, Symmetrical cell test and charge/discharge cell test. As a result, we will introduce the properties of CE with garnet LLZO powder, PEO and PVDF polymers in cathode and solid electrolyte layer. Finally, a pouch-type ASSBs having a bipolar structure in which energy density is improved by applying such a thin SE is described in more detail.

Transport of electrons and ions at carbon surfaces immersed in electrolytes is instrumental for a wide variety of membrane processes as well as energy storage in batteries and supercapacitors. Ion transport in a nanoporous electrode strongly depends on its electronic conductance and on the interfacial capacitance with the electrolyte. In this study, we use in-plane impedance spectroscopy to disentangle in-plane ionic and electronic transport on a single crystal graphene transistor covered by an ionic liquid droplet (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, EMI-TFSI). droplet. Due to the atomic thickness of graphene combined to the strong affinity of EMI+ for carbon, this transistor maximizes ion-electron couplings. Using gate- and temperature-dependent in-plane spectroscopy, we extract both the electronic and ionic conductance of the transistor on a wide range of charge carrier density and over several decades of electrolyte conductivity. We show that despite an exceptionally high capacitive coupling at the carbon-EMI-TFSI interface, the ionic and electronic transport pathways are decoupled at the micrometric scale, in agreement with predicted lengthscales involved in the electronic-ionic interfacial transport.

Lithium-ion batteries (LIBs) have played a pivotal role in advancing energy storage technologies, enabling high-demand applications such as electric vehicles and renewable energy storage systems. Despite their widespread use, LIBs face significant challenges in terms of energy density and intrinsic safety issues. These challenges have spurred interest in all-solid-state batteries (ASSBs), which utilize solid electrolytes (SEs) to offer safe alternatives to conventional liquid electrolyte-based LIBs. Among the various types of SEs explored to date, halide SEs exhibit improved compatibility with high-voltage oxide cathodes, as compared with sulfide-based SEs. Thus, halide SEs may be utilized as cathode coating materials for ASSBs using sulfide SEs with high ionic conductivity. However, the specific material properties that determine the chemical/electrochemical characteristics of halide coatings have not been clearly studied yet.In this study, we synthesize lithium yttrium chloride (Li3YCl6, LYC) SEs using different methods (solid-state synthesis and ammonium-assisted liquid-phase synthesis) at various heat-treatment temperatures to control phase compositions and crystal structures. These allow us to systematically explore the phase-structure-property relationship of LYC SEs and their roles as coating materials for LiNi0.90Co0.05Mn0.05O2 (NCM). Our experimental findings reveal that the phase, crystal structure and crystallinity of LYC significantly influence the microstructure, ionic conductivity, interfacial compatibility, and thermal stability of LYC-coated NCM (NCM@LYC). The crystal structure and crystallinity of synthesized LYC SEs are explored by Rietveld refinement of X-ray diffraction patterns. Notably, LYC SEs prepared via wet synthesis under optimal heat-treatment conditions exhibit superior Li-ion transport kinetics due to the enhanced crystallinity of phase-pure LYC. This leads to the improved interfacial resistances of NCM@LYC, as evidenced by impedance analyses of NCM composite electrodes. Therefore, the NCM@LYC composite electrodes with the optimized LYC SE show significant improvement in rate capability and cycle lifetimes. This research elucidates the critical role of the synthesis conditions in controlling the properties of halide coating materials and thus in improving the interfacial kinetics and stability of composite cathodes of ASSBs. The insights gained from the phase-structure-property relationships provide valuable guidelines for the development of highly conductive and stable SEs for next-generation batteries.

All solid-state batteries (ASSBs) play an indispensable role in modern electronic devices, ranging from cellphones and automobiles to energy storage systems. The performance and lifespan of these devices are highly dependent on the condition of the installed battery. During charge-discharge cycles, batteries undergo microstructural changes, such as void formation, solid electrolyte interphase formation, and dendritic growth at the anode and solid electrolyte (SE) interface. These changes can lead to a reduction in energy storage capacity or even device failure. Therefore, developing stable ASSBs that prevent abrupt microstructural evolution by suppressing dendritic growth is crucial to ensuring safe service during charge/discharge cycles. Meanwhile, utilizing computational methods can provide additional insights and directions regarding the microstructure evolution of ASSBs for further experimental validation.In this study, we explored the use of phase-field modeling to investigate Na dendrite growth behavior in Na and Na-Sb alloy anodes. We find that the dead Na inside grain boundaries of SEs from previous plating/stripping cycles can facilitate further Na dendrite penetration during subsequent cycles. In comparison, the Na₃Sb second phase in the Na-Sb alloy anode can decrease the dendrite penetration depth during cycling. We anticipate that this approach can be applied to showcase various microstructure evolutions in ASSBs, providing insights for suppressing dendrite growth via anode composition and microstructure design.

Metal halide perovskites are promising candidates for low-cost and sensitive x-ray detection. However, the existing perovskite materials with diverse composition and dimensionality encounter an intrinsictrade-off between carrier collection and ion migration, posing a critical challenge for high-energy x-ray detection. Here, we demonstrated that the quasi-one-dimensional perovskite of cystamine lead iodide featuring corner-sharing [Pb5I22] chains chain and small interchain spacing along edge-on orientation enables efficient carrier collection and blocked ion migration simultaneously, and thus largely decouple the electronic and ionic transport pathways. The as-grown single crystals yield a large mobility-lifetime product of 4.35×10-4 cm2 V-1, and a high activation energy for ion migration of 0.94eV. Therefore, an impressive x-ray sensitivity of 1.42×105µC Gy-1 cm-2 (average x-ray energy 42.7keV) are obtained in quasi-one-dimensional perovskite. Under harsh conditions, such as continuous radiation, high electric fields, and high temperatures, the device exhibits excellent operational stability. As a proof of concept, the robust integration of a quasi-one-dimensional perovskite with a thin-film transistor backplane for x-ray imaging was achieved. This study offers innovative insights into the regulate the structural dimensions of materials for sensitive and stable x-ray detection.

Metal fluoride conversion cathodes are promising for the production of cheap, sustainable, and high-energy lithium-ion batteries. Yet, such systems are plagued by active material dissolution that causes capacity fade and hinders commercialization. Here, a covalent netting strategy is proposed to overcome this hurdle. In a proof-of-concept design, polydopamine derived carbon-mediated covalent binding inhibited the dissolution, while the pyrolyzed bacterial cellulose netting structure furnished fast electronic and ionic transport pathways. We demonstrate high-capacity, high-rate and long-lasting stability attained at practical loading levels. Our investigations suggest that the covalent netting-enabled formation of a robust and efficient blocking layer, highly competent in suppressing the leaching, is key for a stable performance. The successful stabilization of metal difluorides in the absence of electrolyte engineering opens an avenue for their practical deployment in future higher-level but lower-cost batteries, and provides a solution to similar challenges encountered by other dissolving energy electrode materials.

All solid-state batteries (ASSBs) are the next generation battery technology, in which the classical liquid electrolyte is replaced by an ion-conducting solid electrolyte. Materials that are used as solid-state electrolytes are generally divided into three material classes: polymers, oxides and sulphides. Electrolyte materials for ASSBs have been extensively studied regarding their electrochemical performance and their stability towards the electrode materials. Nevertheless, the commercialization of ASSBs is still hindered by the material availability in case of oxide and sulphides and the knowledge of scaled production routes for all kinds of separators. Polymers are readily available on the global market. It is thus possible to focus more on the processing routes of polymer based solid electrolytes. The use of thermoplastics as matrix for solid electrolytes (SE) offers the prospect of facile upscaling of the process from lab-scale to industrial series production by the implementation of a solvent-free thermal extrusion process. A twin-screw extruder offers the possibility of continuously mixing the SE components to produce homogeneous polymer based SEs. With two feeding units, the addition of the components takes place separately. This eliminates the time-consuming premixing step to obtain a homogeneous mixture.Thermoplastic poly(ethylene oxide) (PEO) is one of the most investigated materials for polymer based SEs due to its capability to dissolve alkali salts like Lithium(bistrifluoromethanesulfonyl)imide (LiTFSI). The thermal process route of PEO and its effect on the polymeric properties are currently under investigation. Previous works from our research group show that the processability of PEO not only depends on the conductive salt (LiTFSI), but also on its molecular weight and applied process parameters. [1] With increasing molecular weight, PEO becomes more sensitive towards thermal and mechanical load that leads to chain scissoring and degradation even at small load. Hence, the use of low molecular weight PEO (Mw= 100.000 g mol-1) is preferable for the dry production of PEO based SEs.The aim of this work is to optimize the extrusion process using a co-rotating twin-screw extruder for the solvent free production of solid PEO/LiTFSI-electrolytes in a molar ratio of 20:1 (EO:Li). Here, we investigate the effects of several extruder set-ups on the mixing behaviour of PEO and LiTFSI. Therefore, type of dosing and screw design are varied. The screw can be designed with conveying, kneading and mixing elements. We compare the dry extrusion of a premixed PEO/LiTFSI (20:1) batch with dry extrusion of PEO/LiTFSI (20:1) using two feeding units, one for each component. Process parameters, such as pressure at the extruder die, actual screw speed, torque and barrel temperature are continuously measured during the production. Process temperature and screw speed are optimized to avoid degradation of PEO. PEO/LiTFSI-electrolytes are produced with a process temperature of 90 °C across the whole extruder barrel and with screw speeds of 5 – 15 rpm. The products are evaluated by their homogeneity and quality of the extruded electrolytes. Optical microscopy is used for macroscopic evaluation and the Li-salt distribution is checked with SEM/EDX. Conductivity and rheology measurements are performed to determine the lithium concentration within the electrolyte and loss of molecular weight, respectively. For the determination of the ionic conductivity, we examine electrochemical impedance spectroscopy (EIS). The characterization of the extruded electrolytes helps to find optimal process parameters for the production of polymer based SEs.