Conversion Kinetics and Ionic Conductivity in Na-β"-Alumina + YSZ (Naβ"AY) Sodium Solid Electrolyte via Vapor Phase Conversion Process.

A novel sodium‐ion conducting polymer–ceramic solid‐state composite electrolyte is developed for ambient‐temperature sodium batteries. Polyethylene glycol diacrylate (PEGDA) is used as a polymeric matrix into which ceramic nanoparticles of NASICON‐type Na3Zr2Si2PO12 are integrated. The PEGDA polymeric phase of the composite can maintain an amiable ionic interface between the solid‐state electrolyte and electrodes. The Na3Zr2Si2PO12 ceramic phase not only enhances the sodium‐ion conductivity of the composite but also can suppress the Na dendrites from penetrating through the electrolyte membrane. To optimize the Na+‐ion conductivity, a succinonitrile (SCN) plasticizer is also incorporated. The composite solid electrolyte membranes are fabricated with an ultraviolet (UV) curing process. Through proper management of the composition, the PEGDA‐SCN‐Na3Zr2Si2PO12‐NaClO4 composite solid electrolyte delivers an ionic conductivity of 4.5 × 10−4 S cm−1 at room temperature. All‐solid‐state Na cells with the PEGDA‐SCN‐NaClO4‐Na3Zr2Si2PO12 composite electrolyte are fabricated by coupling a Na2MnFe(CN)6 positive electrode to a Na‐metal negative electrode. The resulting Na ‖ PEGDA‐SCN‐NaClO4‐Na3Zr2Si2PO12 ‖ Na2MnFe(CN)6 cells show remarkable cycling stability.

A review of composite polymer-ceramic electrolytes for lithium batteries

Lithium-ion solid-state batteries with spinel Li4Ti5O12 (LTO) electrodes have significant advantages, such as stability, long life, and good multiplication performance. In this work, the LTO electrode was obtained by the atmospheric plasma spraying method, and a composite solid electrolyte was prepared by in situ ultraviolet (UV) curing on the LTO electrode. The composite solid electrolyte was designed using a soft-hard combination strategy, and the electrolyte was prepared into a composite of a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) flexible structure and high-conductivity Li1.3Al0.3Ti1.7(PO4)3 (LATP) hard particles. The composite electrolyte exhibited a good ionic conductivity up to 0.35 mS cm-1 at 30 °C and an electrochemical window above 4.0 V. In situ and ex situ electrolytes were assembled into LTO//electrolyte//Li solid-state batteries to investigate their impact on the electrochemical performance of the batteries. As a result, the assembled Li4Ti5O12//in situ electrolytes//Li batteries exhibited excellent rate of performance, and their capacity retention rate was 90% at 0.2 mA/cm2 after 300 cycles. This work provides a new method for the fabrication of novel advanced solid-state electrolytes and electrodes for applications in solid-state batteries.

Sodium-ion batteries (SIBs) are emerging as a promising alternative to lithium-ion batteries, primarily due to their plentiful raw materials and cost-effectiveness. However, the use of traditional organic liquid electrolytes in sodium battery applications presents significant safety risks, prompting the investigation of solid electrolytes as a more viable solution. Despite their advantages, single solid electrolytes encounter challenges, including low conductivity of sodium ions at room temperature and incompatibility with electrode materials. To overcome these limitations, the researchers develop composite polymer solid electrolytes (CPSEs), which merge the strengths of high ionic conductivity of inorganic solid electrolytes and the flexibility of polymer solid electrolytes. CPSEs are usually composed of inorganic materials dispersed in the polymer matrix. The final performance of CPSEs can be further improved by optimizing the particle size, relative content, and form of inorganic fillers. CPSEs show great advantages in improving ionic conductivity and interface compatibility, making them an important direction for future solid-state sodium battery research. Therefore, this paper summarizes recent advancements in composite solid electrolytes, discusses the impact of their preparation processes on performance, and outlines potential future developments in sodium-ion solid-state batteries.

Finding sodium solid electrolytes (SSEs) with good performance is key to building all-solid-state sodium batteries. In the development of solid electrolytes, halogen doping has been shown to be an effective approach. However, it has rarely been applied to chalcogenide-based SSEs, possibly because of strict structure constraints. In this work, the strategy of halogen doping is successfully demonstrated on Na3.67[Sn0.67Si0.33]0.67P0.33S4, a novel SSE with high structural tolerance. The halogen-doped samples formulated as Na3.57[Sn0.67Si0.33]0.67P0.33S3.9X0.1 (X = Cl, Br, and I) exhibit higher ionic conductivities and lower activation energies than the pristine sample. Na3.57[Sn0.67Si0.33]0.67P0.33S3.9I0.1, the I-doped sample, has the highest ambient ionic conductivity of 1.08 mS cm–1 and the lowest activation energy of 0.24 eV. Structure analysis indicates that the high electronegativity of Cl atoms plays an important role in improving the conduction of Na+ ions in Cl-doped samples. The large atomic radius and high polarizability of I are more important factors to accelerate the transportation of Na+ ions in the I-doped counterpart. Furthermore, the all-solid-state sodium batteries assembled with Na3.57[Sn0.67Si0.33]0.67P0.33S3.9I0.1 as solid electrolytes show decent cyclic stability at 30 °C with a current density of 0.15 A g–1. This work systematically manifests the effect of halogen doping in SSEs, providing a versatile method to develop novel SSEs.

Preparation, characterization and ionic conductivity studies of composite sulfide solid electrolyte

Metal—organic frameworks (MOFs) are intriguing host materials in composite electrolytes due to their ability for tailoring host-guest interactions by chemical tuning of the MOF backbone. Here, we introduce particularly high sodium ion conductivity into the zeolitic imidazolate framework ZIF-8 by impregnation with the sodium-salt-containing ionic liquid (IL) (Na0.1¬EMIM0.9)TFSI. We demonstrate an ionic conductivity exceeding 2×10-4 S ⋅cm-1 at room temperature, with an activation energy as low as 0.26 eV, i.e., the highest reported performance for room temperature Na+-related ion conduction in MOF-based composite electrolytes to date. Partial amorphization of the ZIF-backbone by ball-milling results in significant enhancement of the composite stability, reflecting in persistent and stable ionic conductivity during exposure to ambient air over up to 20 days. While the introduction of network disorder decelerates IL exudation and interactions with ambient contaminants, the ion conductivity is only marginally affected, decreasing linearly with decreasing crystallinity but still maintaining superionic behavior. This highlights the general importance of 3D networks of interconnected pores for efficient ion conduction in MOF/IL blends, whereas pore symmetry is a presumably less stringent condition.

High energy density of solid-state batteries requires a thin solid electrolyte separator layer (<30 μm), that can sustain high currents and is easily processable. Polymer-ceramic composite electrolytes can potentially fulfill these requirements by combining the advantages of each type. Ceramic electrolytes have high room-temperature ionic conductivity, transference number of one, and mechanical strength to suppress lithium dendrites, whereas polymer electrolytes are easily processable and can form conformable interfaces with the electrodes. High interfacial-impedance between polymer and ceramic electrolytes make the composites with dispersed ceramic particles less attractive.1 A composite electrolyte architecture where a three-dimensionally interconnected porous ceramic is filled with polymer electrolyte, previously reported by our group, can avoid the interfacial impedance issue, although for thin composite membranes, the interfacial impedance between ceramic framework and excess polymer layer on top/bottom surface will still dominate the overall impedance.2 Here we will present fabrication and electrochemical evaluation of ~150 μm thick composite electrolytes with the above-described 3D-interconnected ceramic architecture. The 3-D framework is obtained by partially sintering Ohara ceramic particle tapes obtained via tape casting, which are filled with curable polymer electrolyte precursors. To obtain a thin (5 μm), uniform polymer electrolyte layer on both surfaces, spray coating was employed. The resulting composite membrane exhibited good dendritic resistance in symmetric cell cycling, improved transference number compared to the polymer electrolytes. We also found significantly improved flexibility of the composite electrolytes with plasticization, however, at the cost of reduction in ionic conductivity due to damage to the ceramic network caused by plasticizer-induced swelling of the cross-linked polymer electrolyte. This research was sponsored by the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy for the Vehicle Technologies Office’s Advanced Battery Materials Research Program (Tien Duong, Program Manager). This abstract has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). References Chen, X. C.; Liu, X.; Samuthira Pandian, A.; Lou, K.; Delnick, F. M.; Dudney, N. J., Determining and Minimizing Resistance for Ion Transport at the Polymer/Ceramic Electrolyte Interface. ACS Energy Letters 2019, 4 (5), 1080-1085.Palmer, M. J.; Kalnaus, S.; Dixit, M. B.; Westover, A. S.; Hatzell, K. B.; Dudney, N. J.; Chen, X. C., A three-dimensional interconnected polymer/ceramic composite as a thin film solid electrolyte. Energy Storage Materials 2020, 26, 242-249.

A polyethylene oxide/metal-organic framework composite solid electrolyte with uniform Li deposition and stability for lithium anode by immobilizing anions

Advances in lithium-ion battery (LIB) technology have taken center stage over the past decade due to their high energy densities compared to other battery chemistries. However, resource limitations are expected to increase production costs, prompting interest in alternative technologies. Sodium-ion batteries (SIBs), which share similar chemistry with LIBs but rely on more abundant elements, have emerged as promising next-generation energy storage solutions. In this context, solid electrolyte materials are crucial for enabling safe and efficient sodium batteries by mitigating the risks associated with flammable liquid electrolytes. Sodium-Super-Ionic-Conductor (NASICON) structures like Na₃Zr₂Si₂PO₁₂ (NZSP) have attracted considerable attention for their excellent ionic conductivity and thermal stability. However, their practical use is often hindered by inherent porosity and low density, which degrade ionic conductivity and electrochemical stability, ultimately limiting battery performance.In this study, we significantly enhance the performance of NZSP solid electrolyte materials tailored for All-Solid-State batteries (ASSBs) through a successful densification process. By introducing a densification agent that interacts effectively with the sodium-ion conducting matrix, we achieved notable improvements in both material compactness and ionic transport properties. The densified sample exhibited an impressive room-temperature ionic conductivity of 8.4 × 10⁻⁴ S/cm and attained ~98% of the theoretical density, resulting in a robust and mechanically stable electrolyte structure. This process also reduced porosity and grain boundary resistance, enabling faster and more efficient sodium-ion conduction. Comprehensive electrochemical evaluations were conducted to assess the performance of the optimized solid electrolyte. The densified sample exhibited a high critical current density (CCD) of 6 mA cm⁻², which is three times greater than that of the pristine counterpart. This high CCD signifies the ability of the electrolyte to support high rates of sodium-ion transport without significant polarization, a crucial parameter for high-power applications.To further validate the effectiveness of our densification approach, full cells were assembled using the densified NZSP electrolyte paired with a sodium vanadium phosphate (NVP) cathode. These cells exhibited a marked increase in capacity, reflecting the improved ionic conductivity and reduced interfacial resistance achieved through densification. The results demonstrate the practical viability of the optimized electrolyte in real battery systems. Such advancements are crucial for the commercialization of high-energy-density sodium batteries, paving the way for safer and more sustainable energy storage technologies. Figure 1

Currently, electrolytes used in lithium-ion batteries are flammable and leaky, causing safety problems when used under high temperatures or extreme conditions. Solid electrolytes can fundamentally avoid the occurrence of such issues, at the same time, it can significantly increase the energy density of solid state lithium batteries. Solid electrolytes are classified into inorganic solid electrolytes and solid polymer electrolytes. Although inorganic solid electrolytes have the high mechanical strength and room temperature ionic conductivity, it has poor flexibility and complicated preparation process. In contrast, solid polymer electrolyte has good elasticity and good interface contact, which can overcome many disadvantages of the inorganic solid electrolyte. Among them, polyethylene oxide (PEO) is first proposed as a polymer electrolyte. Due to its excellent mechanical properties, electrochemical stability and thermal stability, it has been a hot topic for polymer solid electrolytes for decades. However, its low room temperature ionic conductivity limits practical application. Given the problems existing in PEO-based polymer electrolytes, several methods for improving ionic conductivity have been proposed. The primary methods include plasticization, the organic-inorganic composite, and polymer blending. Comparing these methods, it can be seen that adding plasticizers to the polymer can effectively increase the conductivity of the electrolyte, but at the same time it will cause a decrease in the mechanical properties, and the safety issues limit its application in lithium-ion batteries. Inorganic fillers can balance the problems of ionic conductivity and mechanical properties, but the construction of a good filler-polymer dispersion system is complicated in preparing such composite electrolytes, design a new type of multi-dimensional the ion transport network also face tremendous challenges. Undoubtedly, in the future research, inorganic fillers will be the dominant means in the modification of composite electrolytes. Compared with the former two modification methods, polymer blending is easy to operate and friendly to industry, but low ionic conductivity at room temperature still exist. To give full play to the advantages of polymer blending, using it as an auxiliary means to improve the performance of composite electrolytes will be the primary development direction of such modification methods. PEO is the most widely studied polymer electrolyte. Even though a large number of modification methods have emerged in its development history, the ionic conductivity at room temperature is still limited to a relatively low level. To meet the needs of the application in lithium-ion batteries, a high operating temperature (50−70℃) is still needed, the biggest problem remains exist. To solve the problems in polymer solid electrolytes, the research directions in the future may mainly focus on: Expanding the modification method of PEO to other polymer electrolyte host materials, broadening the scope of research, and finding the available polymer electrolytes at room temperature. Concerned about the preparation of ultra-thin polymer electrolytes, reducing the ion transmission path to increase the transmission efficiency of lithium ions between positive and negative electrodes. Effectively combines inorganic solid electrolytes and solid polymer electrolytes to give full play to their advantages. In addition, exploring the effect of inorganic filler morphology on the conductivity of the composite electrolyte will also deserve attention. Many one-dimensional, two-dimensional materials can build ion transport networks so that lithium ions can travel rapidly along the path. With the deepening of research, it is expected that PEO-based polymer electrolytes may replace liquid electrolytes and become an essential cornerstone for building the next generation of safe and reliable lithium-ion batteries.

Crystal structure, oxygen nonstoichiometry, and mass and charge transport properties of the Sr-free SOFC/SOEC air electrode material La0.75Ca0.25FeO3-δ

Polyethylene oxide (PEO) based-solid polymer electrolytes were prepared with low weight polymers bearing carboxylic acid groups added onto the polymer backbone, and the variation of the conductivity and performance of the resulting Li ion battery system was examined. The composite solid polymer electrolytes (CSPEs) were composed of PEO, LiClO4, PAA (polyacrylic acid), PMAA (polymethacrylic acid), and Al2O3. The addition of additives to the PEO matrix enhanced the ionic conductivities of the electrolyte. The composite electrolyte composed of PEO:LiClO4:PAA/PMAA/Li0.3 exhibited a low polarization resistance of 881.5 ohms in its impedance spectra, while the PEO:LiClO4 film showed a high value of 4,592 ohms. The highest ionic conductivity of 9.87 × 10−4 S cm−1 was attained for the electrolyte composed of PEO:LiClO4:PAA/PMAA/Li0.3 at 20 °C. The cyclic voltammogram of Li+ recorded for the cell consisting of the PEO:LiClO4:PAA/PMAA/Li0.3:Al2O3 composite electrolyte exhibited the same diffusion process as that obtained with an ultra-microelectrode. Based on this electrolyte, the applicability of the solid polymer electrolytes to lithium batteries was examined for an Li/SPE/LiNi0.5Co0.5O2 cell.

A comparison of ionic conductivity, thermal behaviour and morphology in two polyether–LiI–LiAl 5O 8 composite polymer electrolytes

The large amount of waste chemical fiber textiles that exists has posed pressure on the sustainable development of the natural environment and of society. Therefore, it is of great importance to increase the added value of waste chemical fiber textiles and expand their applications in other fields. Herein, acrylic yarn from waste clothing is used as the raw material to construct a three-dimensional (3D) acrylic-based ceramic composite nanofiber solid electrolyte. The electrochemical properties of batteries based on this solid electrolyte are also investigated. We found that the fabricated composite electrolyte has good performance in lithium ion conduction and electrochemical stability because of its 3D acrylic-based ceramic composite fiber framework. The introduction of this composite electrolyte to a lithium symmetric battery enabled the battery to circulate stably for 2350 h at 50 °C without short-circuiting. In addition, all-solid-state batteries using a LiFePO4 cathode exhibited high reversible capacity. Lastly, a flexible lithium metal pouch battery was able to operate safely and stably under extreme conditions. This work demonstrates a strategy for upcycling waste textiles into ion-conducting polymers for energy storage applications.