Solid State Ionics最新文献

The escalating demand for large-scale energy storage solutions has sparked significant interest in metal-ion batteries, particularly in the realm of high-performance anode materials. This work explores the potential of penta-BP₂ as an anode material for sodium and potassium-ion batteries through first-principles calculations. The two-dimensional metallic structure of penta-BP₂ exhibits favorable electrical conductivity, making it an ideal candidate for anode materials. Theoretical analysis reveals that penta-BP₂ can adsorb two layers of Na and three layers of K, resulting in high storage capacities of 1105 and 1473 mAh/g, along with low open-circuit voltages of 0.40 and 0.30 V, respectively. These characteristics enable the production of high energy density in sodium and potassium-ion batteries. Additionally, the material's small Young's modulus and low diffusion energy barriers further establish penta-BP₂ as a flexible anode material capable of rapid charge/discharge processes.

This paper explores the application of nanosized, sintered, non-stoichiometric CeO₂ with six dopants Ce_0.8Nd_0.0025Sm_0.0025Gd_0.005Dy_0.095Y_0.095O_2-δ (CNSGDY), synthesized via modified glycine-nitrate procedure (MGNP) and room temperature self-propagating reaction (SPRT) for fuel cells. The composition, microstructure, and morphology of CNSGDY samples were analyzed using XRD, Raman spectroscopy, SEM, and EDS. The concentration of O²⁻ vacancies, enabling the improvement of ionic conduction, was measured by the deconvolution procedure of additional Raman modes (250 cm⁻¹ (2TA), 560 cm⁻¹ (2LA) and 610 cm⁻¹ (2TO)) and total values for MGNP and SPRT CNSGDY were 15.89% and 16.06%, respectively. Electrochemical performance assessed through EIS ((Electrochemical Impedance Spectroscopy) in the 550–700 °C range revealed a maximum power density of 55 mWcm⁻² at 700 °C with SPRT electrolyte. Additionally, the ionic conductivity of the samples was calculated, with the SPRT sample showing superior performance due to higher ionic conductivity values. Differences in power densities between Pt/SPRT/Pt and Pt/MGNP/Pt cells suggest electrode-electrolyte interface and film thickness impacts, guiding future research.

In this work, polypyrrole (PPy) was used to modify Li_1.04Fe_0.3Mn_0.7PO₄ cathode materials and improve their conductivity. This study found that PPy could form a coating layer and conductive network on the material surface and effectively enhance the conductivity of the material as well as stability of the electrolyte interface. When the amount of PPy addition was 2%, the capacity retention rate at 0.2C and 20 °C was 98.6% after 500 cycles, and the capacity retention rate at −15 °C was 89.0% after 200 cycles. The capacity retention rate of the 2% PPy coated Li_1.04Fe_0.3Mn_0.7PO₄ sample was 20.4% higher than that of the pure Li_1.04Fe_0.3Mn_0.7PO₄ sample after 200 cycles at −15 °C.

This study presents a procedure for creating a surrogate model for the transient electrochemical potential analysis of solid oxide fuel cells (SOFCs) by applying proper orthogonal decomposition (POD), which takes into account the characteristics of the spatial distribution of oxygen potential. In the proposed procedure, the time-variation of oxygen potential distributions in an SOFC are determined by numerical simulations under various analytical conditions with different explanatory variables or, equivalently, input parameters, and the results are stored in a separate data matrix for each component in accordance with certain rules. Then, POD is applied to each data matrix to create an individual surrogate model for the corresponding component using the dominant modes on the basis of contribution rates and/or mean square errors. The created models are used separately to obtain the oxygen potential distribution in the entire domain of the SOFC for an arbitrary set of input parameters at a low computational cost. A notable aspect of the proposed approach is that the positions and values of oxygen potential in two electrodes and interconnectors are data points and responses, respectively, but play opposite roles in the electrolyte region where the oxygen potential changes abruptly. Therefore, before combining the responses from the individual surrogate models, the oxygen potential values must be calculated backward from the coordinate values in the electrolyte. Representative numerical examples are presented to validate the appropriateness of the analysis procedure by applying the surrogate models with input parameters other than those used in the training process in comparison with the results obtained using the transient electrochemical potential.

We have obtained for the first time ferroelectric solid solutions (i.e. ceramic) Li_0.12Na_0.88Ta_yNb_1-yO₃ (y = 0.15, 0.2, 0.25) with the perovskite structure under conditions of high pressures and temperatures. Their electrophysical characteristics have been studied. It has been established that the solid solutions ceramic samples have an orderly distorted crystal structure. The values of static specific conductivities have been determined as functions of temperature, the activation energy of charge carriers, and the real part of the permittivity. It has been established that the samples experience a number of successive phase transitions. For example, P → R → S(T₂). It has been found that the electrical conductivity increases when the content of tantalum increases. The Li_0.12Na_0.88Ta_0.25Nb_0.75O₃ ceramic sample has atypically high electrical conductivity values (close to high ionic conductivity) for this class of solid solutions over the entire studied temperature range. At the same time, the phase is metastable, and heating above the Curie temperature leads to its gradual destruction.

Polybenzimidazoles (PBI) doped with phosphoric acid are a promising electrolyte for medium-temperature fuel cells. However, to be effective at high temperatures in the presence of acid, the mechanical and conductive properties of the material must be stable and no critical increase in gas permeability is required. This work proposes an approach to improve the properties of PBI-O-PhT-based materials by combining two previously known methods: covalent crosslinking with silane (3-bromopropyl)trimethoxysilane (SiBr) and doping with silicon oxide (SiO₂), including grafted imidazolinpropyl groups (SiO₂Im). The silanol cross-linked samples exhibited higher stability when tested with Fenton's reagent and retained their morphological integrity even after 360 h of testing. The study shows that covalent crosslinking improves the stability of dopant particles in the membrane matrix and prevents their leaching during acid treatment. Additionally, the incorporation of silicon oxides enhances the proton conductivity of samples with covalent cross-linking and reduces gas permeability compared to the original PBI membrane. Proton conductivity of the covalent cross-linked samples reaches 50 and 55 mS·cm⁻¹ at oxide contents of 5 wt% SiO₂Im and 10 wt% SiO₂, respectively.

As a new negative material for sodium-ion batteries, NaTi₂(PO₄)₃ has received great attention because of its excellent safety, abundant natural resources, low toxicity and two-electron reactions. However, the pure NaTi₂(PO₄)₃ anode material displays a bad conductivity, resulting in an inferior electrochemical performance for sodium energy storage. In this work, we introduce a good route to fabricate the conductive PTh-promoted NaTi₂(PO₄)₃ (NaTi₂(PO₄)₃@PTh) composite with superior rate property and superior cycle stability for the first time. In this fabricated material, the conductive PTh layer has been successfully coated on the NaTi₂(PO₄)₃ nanoparticles. Compared to NaTi₂(PO₄)₃, the prepared NaTi₂(PO₄)₃@PTh anode possesses better cycle stability and higher capacity. It shows the capacity of 129.5 mAh g⁻¹ at 0.1C and presents the high capacity retention of around 98.3% at 10C over 300 cycles. Therefore, this fabricated NaTi₂(PO₄)₃@PTh nanocomposite can be employed as the novel negative electrode in sodium-ion storage.

We have reported that Zr substitution for Y in Ba₃Y₄O₉ enhances the chemical stability in humidified atmospheres at intermediate temperatures and the Zr-substituted Ba₃Y₄O₉ exhibits oxide-ion conduction probably mediated by oxide-ion vacancies. However, in addition to the problem of Si contamination in the samples, the long-time chemical stability and the transport number of ionic conductions were uncleared. In this work, we revisited the chemical stability and conductivity behavior of Ba₃Y₄O₉ with Zr substitution prepared by a modified procedure to suppress the contamination. Besides, we prepared Ba₃Y₄O₉ substituted by the other tetravalent cations (Ce, Sn, and Ti) and investigated the difference in the material properties from the Zr substitution samples. We carried out powder X-ray diffraction analyses for the evaluation of chemical stability in humidified atmospheres and electrochemical impedance spectroscopy to measure total conductivities of the substituted Ba₃Y₄O₉. As a result, we confirmed that Ce and Sn as well as Zr can substitute 20 mol% Y in Ba₃Y₄O₉ whereas the solubility of Ti in Ba₃Y₄O₉ is about 3 mol% at 1600 °C. Besides, the chemical stability of the substituted Ba₃Y₄O₉ strongly depended on not only the substitution level but also the substitution elements. Moreover, the substituted Ba₃Y₄O₉ was considered to be an almost pure oxide-ion conductor because of the little sensitivity of electrical conductivity to both humidity and partial oxygen pressure.

Given the rising need for energy storage systems with high energy density and extended durability, lithium‑sulfur batteries have garnered interest due to their elevated theoretical specific capacity and energy density. However, the practical application of lithium‑sulfur (LiS) batteries faces several obstacles, including the low conductivity of sulfur and the dissolution of lithium polysulphides during cycling, leading to low cycling stability and capacity degradation. In this study, which is dedicated to solving the problems of poor conductivity and dissolution of polysulfides faced by lithium‑sulfur (LiS) batteries in practical applications, NiCoMnSe electrode materials were successfully synthesised by employing ZIF-67 as a template and optimised by the addition of carbon nanotubes (CNT). The unique structure and excellent performance of the NiCoMnSe-CNT-2 composites were verified by various characterisation means. The experimental results show that the initial charge-discharge capacity of NiCoMnSe-CNT-2 composite is as high as 1387.3 mAh/g at a current density of 0.2C. After 200 charge-discharge cycles, the specific capacity of NiCoMnSe-CNT-2 composite can still remain at 1084.86 mAh/g. The study therefore makes an important contribution to progress in the field of clean energy storage.

Lithium-ion conducting oxides, prepared by conventional ball-milling and subsequently calcination at high temperatures, are always in microscales, which inevitably limits their application in composite metallic anodes. Herein, 20 nm-scaled Li_6.1Ga_0.3La₃Zr₂O₁₂ (LLZO) and 10 nm-scaled Li_0.3La_0.57TiO₃ (LLTO) oxides are fabricated by a modified sol-gel-calcination method. The gelation by the esterification reaction between citric acid and ethylene glycol potential create nanoscale zones in the molecular-level homogeneous mixed solution, resulting in LLTO and LLZO nanoparticles separated by carbonized productions. These carbonized products could suppress the growth of nanoparticles into micrometers in the oxidation process of these residual products, and finally, nanoscale LLTO and LLZO lithium-ion conducting oxides were evented. Solid electrolytes prepared using nanoscale LLTO and LLZO deliver comparable high ionic conductivities, indicating promising applications in all-solid-state lithium batteries.