Mechanical Properties of Rock Salt from the Klodawa Salt Dome-A Statistical Analysis of Geomechanical Data.

Rock salt is a potential medium for underground storage of energy resources and radioactive substances due to its physical and mechanical properties, distinguishing it from other rock media. Designing storage facilities that ensure stability, tightness, and safety requires understanding the geomechanical properties of rock salt. Despite numerous research efforts on the behaviour of rock salt mass, many cases still show unfavourable phenomena occurring within it. Therefore, the formulation of strength criteria in a three-dimensional stress state and the prediction of deformation processes significantly impact the functionality of storage in salt caverns. This article presents rock salt's mechanical properties from the Klodawa salt dome and a statistical analysis of the determined geomechanical data. The analysis is divided into individual mining fields (Fields 1-6). The analysis of numerical parameter values obtained in uniaxial compression tests for rock salt from mining Fields 1-6 indicates an average variation in their strength and deformation properties. Upon comparing the results of Young's modulus (E) with uniaxial compressive strength (UCS), its value was observed with a decrease in uniaxial compressive strength (E = 4.19968·UCS2, R-square = -0.61). The tensile strength of rock salt from mining Fields 1-6 also exhibits moderate variability. An increasing trend in tensile strength was observed with increased bulk density (σt = 0.0027697·ρ - 4.5892, r = 0.60). However, the results of triaxial tests indicated that within the entire range of normal stresses, the process of increasing maximum shear stresses occurs linearly ((σ1 - σ3)/2 = ((σ1 + σ3)/2)·0.610676 + 2.28335, r = 0.92). A linear relationship was also obtained for failure stresses as a function of radial stresses (σ1 = σ3·2.51861 + 32.9488, r = 0.73). Based on the results, the most homogeneous rock salt was from Field 2 and Field 6, while the most variable rock salt was from Field 3.

Alleviating Structure Collapse of Polycrystalline LiNixCoyMn1-x-yO2 via Surface Co Enrichment.

The structure collapse issues have long restricted the application of polycrystalline LiNixCoyMn1-x-yO2 (NCM) at high voltages beyond 4.4 V vs Li/Li+. Herein, for LiNi0.55Co0.12Mn0.33O2 (P-NCM), rapid surface degradation is observed upon the first charge, along with serious particle fragmentation upon repeated cycles. To alleviate these issues, a surface Co enrichment strategy is proposed [i.e., Co-enriched NCM (C-NCM)], which promotes the in situ formation of a robust surface rock-salt (RS) layer upon charge, serving as a highly stable interface for effective Li+ migration. Benefiting from this stabilized surface RS layer, Li+ extraction occurs mainly through this surface RS layer, rather than along the grain boundaries (GBs), thus reducing the risk of GBs' cracking and even particle fragmentation upon cycles. Besides, O loss and TM (TM = Ni, Co, and Mn) dissolution are also effectively reduced with fewer side reactions. The C-NCM/graphite cell presents a highly reversible capacity of 205.1 mA h g-1 at 0.2 C and a high capacity retention of 86% after 500 cycles at 1 C (1 C = 200 mA g-1), which is among the best reported cell performances. This work provides a different path for alleviating particle fragmentation of NCM cathodes.

Dynamic characteristics and evolution laws of underground brine in Mahai salt lake of Qaidam Basin during mining process.

In the late stage of underground brine mining in salt lakes, the method of injecting fresh water is often used to extract the salt from the brine storage medium. This method of freshwater displacement breaks the original water-rock equilibrium and changes the evolution process of the original underground brine. To explore the mechanism of salt release in saline water-bearing media under conditions of relatively fresh lake water dissolution, this paper analyzes the changes in the chemical parameters of brine from 168 sampling points in the Mahai salt lake in the Qaidam Basin at three stages (before exploitation, during exploitation, and late exploitation) by correlation analysis, ion ratio analysis, and other methods and investigate the variations in porosity and the evolution laws of brine. The results show that the changes in the main ion content and brine mineralization during the exploitation process are small. The changes in Ca2+ content are significant due to the low solubility of calcium minerals, the precipitation of gypsum during the mixing process, and the adsorption of cations by alternating with Ca2+. Primary intergranular pore skeletons are easily corroded to form secondary pores, which increase the geological porosity. Na+ and Cl- are the dominant ions in the brine in the study area, but the concentration of Ca2 + decreased significantly under the influence of mining, by 41.7% in the middle period and 24.5% in the late period. The correlation between Ca2+ and salinity changes significantly in different mining stages, and the reason for the decrease of Ca2+ may be due to the influence of mineral dissolution, mixing, and anion-cation exchange. The porosity of the layer in the study area showed the opposite trend of Ca2+, and the porosity increased first and then decreased. The innovation of this paper lies in analyzing the reasons and mechanisms of the disturbance of artificial dissolution mining on stratum structure by comparing the hydrochemical characteristics and porosity of underground brine storage media in three different mining stages. The research in this paper provides a theoretical basis for the calculation of brine resource reserves and the sustainable development of underground brine in salt lake areas.

Enhancing the Electrochemical Performances of Disordered Li1.23Ni0.3Nb0.3Fe0.16O0.85F0.15 Cathode Material for Lithium-Ion Batteries by LiNbOx Coating.

For the next generation of lithium-ion batteries (LIBs), it is primary to seek high capacity and long-lifetime electrode materials. Li-excess disordered rock-salt structure (DRS) cathodes have gained much attention due to their high specific capacity. However, Li-excess can lead to a decrease in the structural stability of an electrode material. A new Li-rich DRS oxyfluorides, Li1.23Ni0.3Nb0.3Fe0.16O0.85F0.15 (F0.15) with a series amounts of LiNbOx (LN) coating (0, 5, 10, and 15 wt % denoted as F0.15-LN0, F0.15-LN5, F0.15-LN10, and F0.15-LN15, respectively), are successfully synthesized and evaluated as cathode materials in LIBs. Among them, F0.15-LN10 exhibits the highest initial discharge specific capacity of 296.1 mAh g-1 (at a current density of 20 mA g-1) with the capacity retention rate of 14% higher than that of the uncoated F0.15 after 80 cycles. Even at 300 mA g-1, F0.15-LN10 still delivers the highest discharge specific capacity of 130 mAh g-1. After 20 cycles, the charge-transfer impedance of F0.15-LN10 remained the smallest. The characterizations indicate that LN coating reduces the surface polarization of the cathode materials, slows the interfacial side reactions between the electrolyte and the electrode, and speeds up the Li+ diffusion. These results demonstrate that LN coating is an effective strategy to improve the electrochemical performance.

Non-Fluorinated Ethers to Mitigate Electrode Surface Reactivity in High-Voltage NCM811-Li Batteries.

Lithium (Li) metal batteries (LMBs) with nickel (Ni)-rich layered oxide cathodes exhibit twice the energy density of conventional Li-ion batteries. However, their lifespan is limited by severe side reactions caused by high electrode reactivity. Fluorinated solvent-based electrolytes can address this challenge, but they pose environmental and biological hazards. This work reports on the molecular engineering of fluorine (F)-free ethers to mitigate electrode surface reactivity in high-voltage Ni-rich LMBs. By merely extending the alkyl chains of traditional ethers, we effectively reduce the catalytic reactivity of the cathode towards the electrolyte at high voltages, which suppresses the oxidation decomposition of the electrolyte, microstructural defects and rock-salt phase formation in the cathode, and gas release issues. The high-voltage Ni-rich NCM811-Li battery delivers capacity retention of 80 % after 250 cycles with a high Coulombic efficiency of 99.85 %, even superior to that in carbonate electrolytes. Additionally, this strategy facilitates passivation of the Li anode by forming a robust solid-electrolyte interphase, boosting the Li reversibility to 99.11 % with a cycling life of 350 cycles, which outperforms conventional F-free ether electrolytes. Consequently, the lifespan of practical LMBs has been prolonged by over 100 % and 500 % compared to those in conventional carbonate- and ether-based electrolytes, respectively.

Deeply Lithiated Carbonaceous Materials for Great Lithium Metal Protection in All-Solid-State Batteries.

Protection of lithium (Li) metal electrode is a core challenge for all-solid-state Li metal batteries (ASSLMBs). Carbon materials with variant structures have shown great effect of Li protection in liquid electrolytes, however, can accelerate the solid-state electrolyte (SE) decomposition owing to the high electronic conductivity, seriously limiting their application in ASSLMBs. Here, a novel strategy is proposed to tailor the carbon materials for efficient Li protection in ASSLMBs, by in situ forming a rational niobium-based Li-rich disordered rock salt (DRS) shell on the carbon materials, providing a favorable percolating Li+ diffusion network for speeding the carbon lithiation, and enabling simultaneously improved lithiophilicity and reduced electronic conductivity of the carbon structure at deep lithiation state. Using the proposed strategy, different carbon materials, such as graphitic carbon paper and carbon nanotubes, are tailored with great ability to speed the interfacial kinetics, homogenize the Li plating/stripping processes, and suppress the SE decompositions, enabling much improved performances of ASSLMBs under various conditions approaching the practical application. This strategy is expected to create a novel roadmap of Li protection for developing reliable high-energy-density ASSLMBs.

Electrochemical Nitrogen Reduction to Ammonia at Ambient Condition on the (111) Facets of Transition Metal Carbonitrides.

We conducted Density Functional Theory calculations to investigate a class of materials with the goal of enabling nitrogen activation and electrochemical ammonia production under ambient conditions. The source of protons at the anode could originate from either water splitting or H2, but our specific focus was on the cathode reaction, where nitrogen is reduced into ammonia. We examined the conventional associative mechanism, dissociative mechanism, and Mars-van Krevelen mechanism on the (111) facets of the NaCl-type structure found in early transition metal carbonitrides, including Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Sc, Y, and W. We explored the catalytic activity by calculating the free energy of all intermediates along the reaction pathway and constructing free energy diagrams to identify the steps that determine the reaction's feasibility. Additionally, we closely examined the potential for catalyst poisoning within the electrochemical environment, considering the bias required to drive the reaction. Furthermore, we assessed the likelihood of catalyst decomposition and the potential for catalyst regeneration among the most intriguing carbonitrides. Our findings revealed that the only carbonitride catalyst considered here exhibiting both activity and stability, capable of self-regeneration and nitrogen-to-ammonia activation, is NbCN with a low potential-determining step energy of 0.58 eV. This material can facilitate ammonia formation via a mixed associative-MvK mechanism. In contrast, other carbonitrides of this crystallographic orientation are likely to undergo decomposition, reverting to their parent metals under operational conditions.

In Situ Phase-Transformation Forming a Bicontinuous (Ni, Co, Ti, and Al)-Oxide/Li2CO3 Interpenetrating Network Electrolyte for Solid Oxide Fuel Cells.

Designing heterogeneous electrolytes with superior interface charge transfer is promising for low-temperature solid oxide fuel cells (LT-SOFCs). However, a rational construction with optimal interfaces to maximize ionic conduction remains a challenge. Here an in situ phase-transformation strategy is demonstrated to prepare a highly conductive heterogeneous electrolyte. A pristine LiNiO2-TiO2 nanocomposite precursor undergoes chemical reactions and phase-transformation upon heating and feeding H2, destroying the original phases, and forming new species, including an amorphous Li2CO3 scaffold within a (Ni, Co, Al, and Ti)-oxide (NCAT) matrix. It creates an intertwining and continuous network inside the electrolyte with plentiful interfaces. The in situ formed NCAT/Li2CO3 heterogeneous electrolyte displays superior ionic conductivity and impressive fuel cell performance. This work emphasizes the potential of rational heterogeneous structure design and interface engineering for LT-SOFC electrolyte through an in situ phase-transform approach. The generated interfaces enhance ion transport, presenting an opportunity for further optimizing electrolyte candidates, and lowering the operating temperatures of SOFCs.

Exploring the Role of an Electrolyte Additive in Suppressing Surface Reconstruction of a Ni-Rich NMC Cathode at Ultrahigh Voltage via Enhanced In Situ and Operando Characterization Methods.

Vinylene carbonate (VC) is a widely used electrolyte additive in lithium-ion batteries for enhanced solid electrolyte interphase formation on the anode side. However, the cathode electrolyte interphase (CEI) formation with VC has received a lot less attention. This study presents a comprehensive investigation employing advanced in situ/operando-based Raman and X-ray absorption spectroscopy (XAS) to explore the effect of electrolyte composition on the CEI formation and suppression of surface reconstruction of LixNiyMnzCo1-y-zO2 (NMC) cathodes. A novel chemical pathway via VC polymerization is proposed based on experimental results. In situ Raman spectra revealed a new peak at 995 cm-1, indicating the presence of C-O semi-carbonates resulting from the radical polymerization of VC. Operando Raman analysis unveiled the formation of NiO at 490 cm-1 in the baseline system under ultrahigh voltage (up to 5.2 V). However, this peak was conspicuously absent in the VC electrolyte, signifying the effectiveness of VC in suppressing surface reconstruction. Further investigation was carried out utilizing in situ XAS compared X-ray absorption near edge structure spectra from cells of 3 and 20 cycles in both electrolytes at different operating voltages. The observed shift at the Ni K-edge confirmed a more substantial reduction of Ni in the baseline electrolyte compared to that in the VC electrolyte, thus indicating less CEI protection in the former. A sophisticated extended X-ray absorption fine structure analysis quantitatively confirmed the effective suppression of rock-salt formation with the VC electrolyte during the charging process, consistent with the operando Raman results. The in situ XAS results thus provided additional support for the key findings of this study, establishing the crucial role of VC polymerization in enhancing CEI stability and mitigating surface reconstruction on NMC cathodes. This work clarifies the relationship between the enhanced CEI layer and NMC degradation and inspires rational electrolyte design for long-cycling NMC cathodes.

Protonation Stimulates the Layered to Rock Salt Phase Transition of Ni-Rich Sodium Cathodes.

Protonation of oxide cathodes triggers surface transition metal dissolution and accelerates the performance degradation of Li-ion batteries. While strategies are developed to improve cathode material surface stability, little is known about the effects of protonation on bulk phase transitions in these cathode materials or their sodium-ion battery counterparts. Here, using NaNiO2 in electrolytes with different proton-generating levels as model systems, a holistic picture of the effect of incorporated protons is presented. Protonation of lattice oxygens stimulate transition metal migration to the alkaline layer and accelerates layered-rock-salt phase transition, which leads to bulk structure disintegration and anisotropic surface reconstruction layers formation. A cathode that undergoes severe protonation reactions attains a porous architecture corresponding to its multifold performance fade. This work reveals that interactions between electrolyte and cathode that result in protonation can dominate the structural reversibility/stability of bulk cathodes, and the insight sheds light for the development of future batteries.

Tuning Li2MnO3-Like Domain Size and Surface Structure Enables Highly Stabilized Li-Rich Layered Oxide Cathodes.

Severe capacity/voltage fading still poses substantial obstacles in the commercial applications of Li-rich layered oxides, which stems from the aggregation of Li2MnO3-like domains and unstable surface structure. Here, we report highly stabilized Co-free Li1.2Ni0.2Mn0.6O2 with uniformly dispersed Li2MnO3-like domains and a protective rock-salt structure shell by reducing the oxygen partial pressure during high-temperature calcination. Experimental characterizations and DFT calculations reveal that the uniformly dispersed and small-sized Li2MnO3-like domains suppress the peroxidation of lattice oxygen, enabling highly reversible oxygen redox and excellent structural stability. Moreover, the induced rock-salt structure shell significantly restrains lattice oxygen release, TM dissolution, and interfacial side reactions, thereby improving the interfacial stability and facilitating Li+ diffusion. Consequently, the obtained Li1.2Ni0.2Mn0.6O2 which was calcinated under an oxygen partial pressure of 0.1% (LNMO-0.1) delivers a high reversible capacity of 276.5 mAh g-1 at 0.1 C with superior cycling performance (a capacity retention rate of 85.4% after 300 cycles with a small voltage fading rate of 0.76 mV cycle-1) and excellent thermal stability. This work links the synthesis conditions with the domain structure and electrochemical performance of Li-rich cathode materials, providing some insights for designing high-performance Li-rich cathodes.

High-Pressure Synthesis of Cubic ZnO and Its Solid Solutions with MgO Doped with Li, Na, and K.

The possibility of doping ZnO in its metastable rock salt structure with Li, Na, and K intended to act as acceptor dopants was investigated. For the first time, MgxZn1-xO alloys and pure ZnO with a rock salt structure doped with Li, Na, and K metals was obtained by high-pressure synthesis from pure oxides with the addition of carbonates or acetates of the corresponding metals as dopant sources. Successful stabilization of the metastable rock salt structure and phase purity were confirmed by X-ray diffraction. Transmission electron microscopy was used to study the particle size of nanocrystalline precursors, while the presence of Li, Na, and K metals in rock salt ZnO was detected by electron energy-loss spectroscopy and X-ray photoelectron spectroscopy in MgxZn1-xO alloys. Electron paramagnetic resonance measurements revealed the acceptor behavior of Li, Na, and K dopants based on the influence of the latter on native defects and natural impurities in ZnO-MgO alloys. In addition, diffuse reflectance spectroscopy was used to derive band gaps of quenched rock salt ZnO and its alloys with MgO.

Charge Storage Mechanism in Electrospun Spinel-Structured High-Entropy (Mn0.2 Fe0.2 Co0.2 Ni0.2 Zn0.2 )3 O4 Oxide Nanofibers as Anode Material for Li-Ion Batteries.

High-entropy oxides (HEOs) have emerged as promising anode materials for next-generation lithium-ion batteries (LIBs). Among them, spinel HEOs with vacant lattice sites allowing for lithium insertion and diffusion seem particularly attractive. In this work, electrospun oxygen-deficient (Mn,Fe,Co,Ni,Zn) HEO nanofibers are produced under environmentally friendly calcination conditions and evaluated as anode active material in LIBs. A thorough investigation of the material properties and Li+ storage mechanism is carried out by several analytical techniques, including ex situ synchrotron X-ray absorption spectroscopy. The lithiation process is elucidated in terms of lithium insertion, cation migration, and metal-forming conversion reaction. The process is not fully reversible and the reduction of cations to the metallic form is not complete. In particular, iron, cobalt, and nickel, initially present mainly as Fe3+ , Co3+ /Co2+ , and Ni2+ , undergo reduction to Fe0 , Co0 , and Ni0 to different extent (Fe < Co < Ni). Manganese undergoes partial reduction to Mn3+ /Mn2+ and, upon re-oxidation, does not revert to the pristine oxidation state (+4). Zn2+ cations do not electrochemically participate in the conversion reaction, but migrating from tetrahedral to octahedral positions, they facilitate Li-ion transport within lattice channels opened by their migration. Partially reversible crystal phase transitions are observed.

Toxicity and chemical composition of commercial road palliatives versus oil and gas produced waters.

Across the United States, road palliatives are applied to roads for maintenance operations that improve road safety. In the winter, solid rock salts and brine solutions are used to reduce the accumulation of snow and ice, while in the summer, dust suppressants are used to minimize fugitive dust emissions. Many of these products are chloride-based salts that have been linked to freshwater salinization, toxicity to aquatic organisms, and damage to infrastructure. To minimize these impacts, organic products have been gaining attention, though their widespread adoption has been limited due to their higher cost. In some states, using produced water from conventionally drilled oil and gas wells (OGPWs) on roads is permitted as a cost-effective alternative to commercial products, despite its typically elevated concentrations of heavy metals, radioactivity, and organic micropollutants. In this study, 17 road palliatives used for winter and summer road maintenance were collected and their chemical composition and potential human toxicity were characterized. Results from this study demonstrated that liquid brine solutions had elevated levels of trace metals (Zn, Cu, Sr, Li) that could pose risks to human and environmental health. The radium activity of liquid calcium chloride products was comparable to the activity of OGPWs and could be a significant source of radium to the environment. The organic fractions of evaluated OGPWs and chloride-based products posed little risk to human health. However, organic-based dust suppressants regulated toxicity pathways related to xenobiotic metabolism, lipid metabolism, endocrine disruption, and oxidative stress, indicating their use could lead to environmental harm and health risks to operators handing these products and residents living near treated roads.

Quantifying Degradation Parameters of Single-Crystalline Ni-Rich Cathodes in Lithium-Ion Batteries.

Single-crystal LiNix Coy Mnz O2 (SC-NCM, x+y+z=1) cathodes are renowned for their high structural stability and reduced accumulation of adverse side products during long-term cycling. While advances have been made using SC-NCM cathode materials, careful studies of cathode degradation mechanisms are scarce. Herein, we employed quasi single-crystalline LiNi0.65 Co0.15 Mn0.20 O2 (SC-NCM65) to test the relationship between cycling performance and material degradation for different charge cutoff potentials. The Li/SC-NCM65 cells showed >77 % capacity retention below 4.6 V vs. Li+ /Li after 400 cycles and revealed a significant decay to 56 % for 4.7 V cutoff. We demonstrate that the SC-NCM65 degradation is due to accumulation of rock-salt (NiO) species at the particle surface rather than intragranular cracking or side reactions with the electrolyte. The NiO-type layer formation is also responsible for the strongly increased impedance and transition-metal dissolution. Notably, the capacity loss is found to have a linear relationship with the thickness of the rock-salt surface layer. Density functional theory and COMSOL Multiphysics modeling analysis further indicate that the charge-transfer kinetics is decisive, as the lower lithium diffusivity of the NiO phase hinders charge transport from the surface to the bulk.

Regulating the Anion Redox and Suppressing the Structural Distortion of Cation-Disordered Rock-Salt Cathode Materials to Improve Cycling Durability through Chlorine Substitution.

Owing to the capacity boost from anion redox activities, cation-disordered rock-salt oxides are considered as potential candidates for the next-generation of high energy density Li-ion cathode materials. Unfortunately, the anion redox process that affords ultra-high specific capacity often triggers irreversible O2 release, which brings about structural degradation and rapid capacity decay. In this study, we present a partial chlorine (Cl) substitution strategy to synthesize a new cation-disordered rock-salt compound of Li1.225Ti0.45Mn0.325O1.9Cl0.1 and investigate the impact of Cl substitution on the oxygen redox process and the structural stability of cation-disordered rock-salt cathodes. We find that partial replacement of O2- by Cl- expands the cell volume and promotes anion redox reaction reversibility, thus increasing the Li+ ion diffusion rate and suppressing irreversible lattice oxygen loss. As a result, the Li1.225Ti0.45Mn0.325O1.9Cl0.1 cathode exhibits significantly improved cycling durability at high current densities, compared with the pristine Li1.225Ti0.45Mn0.325O2 cathode. This work demonstrates the promising feasibility of the Cl substitution process for advanced cation-disordered rock-salt cathode materials.

δ34S and Geochemical Analyses for the Determination of, and Discrimination between, Salt Samples of Different Geographic Origin: A Feasibility Study.

The geographic origin of salt is usually regarded as unimportant, as it is a one-quality product produced in vast quantities. However, certain salt brands, especially sea salt (fleur de sel), are sold at significantly higher prices. Thus, it is necessary to control the declared geographic origin of salt. Such controls are already frequently carried out for foodstuffs, but salt is an inorganic commodity. Thus, δ34S analysis combined with element concentration analysis was carried out. The results show very similar δ34S values for all sea salt samples, which is to be expected due to the homogenous marine δ34S value. Still, slightly higher values have been found in Mediterranean salt samples. Rock salt samples show differing δ34S values depending on the time they were formed, and if the salt samples are of marine or terrestrial origin. Terrestrial/continental salt samples are characterized by elemental patterns significantly differing from marine ones. However, within marine samples (sea salt and rock salt) there also exist differences enabling the differentiation of samples.

Towards commercialization of fluorinated cation-disordered rock-salt Li-ion cathodes.

Cation-disordered rock-salt cathodes (DRX) are promising materials that could deliver high capacities (>250 mAh g-1) with Earth abundant elements and materials. However, their electrochemical performances, other than the capacity, should be improved to be competitive cathodes, and many strategies have been introduced to enhance DRXs. Fluorination has been shown to inhibit oxygen loss and increase power density. Nevertheless, fluorinated cation-disordered rock-salts still suffer from rapid material deterioration and low scalability which limit their practical applications. This mini-review highlights the key challenges for the commercialization of fluorinated cation-disordered rock-salts, discusses the underlying reasons behind material failure and proposes future development directions.

High-Performance PEO-Based All-Solid-State Battery Achieved by Li-Conducting High Entropy Oxides.

A rock-salt-structured Li-conducting high entropy oxide was prepared and utilized as an active filler in a polyethylene oxide (PEO)-based solid-state composite electrolyte. X-ray diffraction and high-resolution transmission electron microscopy were adopted to analyze the crystal structure of the high entropy oxide containing 20% of Li ions (HL20). The HL20 was crystallized in the Fm3̅m space group with Li+ ions located at the center of the MO6 octahedra. The ionic conductivity of the composite membrane at 30 °C reaches 3.44 × 10-5 S cm-1. The inflection point of activation energy of the membrane with HL20 decreases by 5 °C compared with that of the pure PEO membrane. In the galvanostatic plating/stripping test, the Li||Li symmetric batteries could be cycled at a current density of 200 µA cm-2 for over 1200 h with an overpotential of 140 mV. The Li||LiFePO4 full battery could be charged/discharged at 0.5 C for 100 circles with a high capacity retention rate of 91%. Excellent rate performance is also achieved at lower temperatures and higher rates, showing the superiority of HL20 as an active filler. This work sheds light on the development of high entropy oxide as a new type of fast ionic conductor, promoting the practical application of all-solid-state batteries at a lower temperature.

[Meta analysis of rock salt aerosol therapy for respiratory tract diseases].

Objective: To systematically evaluate the efficacy and safety of rock salt aerosol in the treatment of respiratory tract diseases. Methods: In June 2021, the clinical randomized controlled trial literatures of rock salt aerosol therapy for respiratory tract diseases were searched from CNKI, Wanfang, VIP, Cochrane Library, PubMed database and EMBASE database. Cochrane risk bias evaluation tool was used to evaluate risk bias, Revman 5.4 and Stata16 were used to conduct meta-analysis, TSA 0.9 was used to conduct sequential analysis of trials, and gradepro was used to evaluate evidence quality. Results: A total of 21 literatures were included. According to whether the subjects received rock salt aerosol therapy, they were divided into the experimental group (1125 people) and the control group (973 people) . Compared with the control group, the total clinical effective rate (RR=1.22, 95%CI: 1.15~1.29, P<0.001) , forced expiratory volume in one second (FEV(1)) (WMD=0.20, 95%CI: 0.09~0.31, P<0.001) , percentage of FEV(1) in the predicted value (FEV(1)%) (WMD=5.06, 95%CI: 3.47~6.65, P<0.001) , forced vital capacity (FVC) (WMD=0.22, 95% CI: 0.16~0.27, P<0.001) , maximum expiratory flow (PEF) (WMD=21.312, 95%CI: 9.189~33.435, P=0.004) of experimental group were higher. TSA test shows that the difference conclusions of total effective rate, FEV(1), FEV(1)%, FVC and PEF were reliable, but the conclusion of FEV(1)% needs to be treated with caution; Three literatures reported the adverse reactions in the experimental group; GRADE evidence quality evaluation showed 3 very low-quality evidences and 2 low-quality evidences. Conclusion: Rock salt aerosol therapy combined with conventional therapy has a certain effect on the treatment of respiratory tract diseases, which needs to be further confirmed by high-quality evidence.