Bulk Stability Research Articles

Confining Surface Oxygen Redox in Double Perovskites for Enhanced Oxygen Evolution Reaction Activity and Stability

AbstractNickel‐based double perovskites AA′BB′O6 are an underexplored class of oxygen evolution reaction (OER) catalysts, in which B‐site substitution is used to tune electronic and structural properties. BaSrNiWO6, with a B‐site comprised of alternating Ni and W, exhibits high oxygen evolution activity, attributed to the evolution of a highly OER active surface phase. The redox transformation of Ni2+(3d8) to Ni3+(3d7) combined with partial W dissolution into the electrolyte from the linear Ni(3d)‐O(2p)‐W(5d) chains drives an in situ reconstruction of the surface to an amorphized, NiO‐like layer, promoting oxygen redox in the OER mechanism. However, the high valence W6+(5d0) acts as a stabilizing electronic influence in the bulk, preventing the mobilization of lattice oxygen which is bound in highly covalent W─O bonds. It is proposed that the surface generated during the OER can support a lattice oxygen evolution mechanism (LOEM) in which oxygen vacancies are created and preferentially refilled by electrolytic OH−, while bulk O species remain stable. This surface LOEM (sLOEM) allows BaSrNiWO6 to retain structural integrity during OER catalysis. With a Tafel slope of 45 mV dec−1 in 0.1 m KOH, BaSrNiWO6 illustrates the potential of Ni‐based double perovskites to offer both OER efficiency and bulk stability in alkaline electrolysis.

Advancing all-polymer solar cells with solid additives

AbstractAll-polymer solar cells (all-PSCs) have attracted significant research attention in recent years, primarily due to their advantages of outstanding photo-thermal stability and excellent mechanical flexibility. However, all-PSCs typically exhibit complex morphologies during the film formation of blend films, primarily due to the tendency to become entangled in polymer chains, negatively impacting their fill factor (FF) and morphology stability. Therefore, the optimization of the morphology of the co-mingled heterojunction is crucial for improving device performance. Recent studies reveal that solid additives (SAs) can realize the excellent regulation of the molecular aggregation state, molecular packing, and domain size of the active layer, which not only improves the exciton dissociation, charge transport and collection process of the device but also ultimately realizes the enhancement of the device efficiency. Therefore, this review provides an in-depth insight into the different mechanisms of solid additives in all-PSCs, offering a comprehensive discussion on the research progress in optimizing the morphology and enhancing morphology stability. Finally, we present an outlook for the further structural modification strategies of solid additives towards better bulk morphology and stability of all-PSCs, paving the way for achieving excellent photo-thermal stability, superior mechanical flexibility, and high-efficiency all-PSCs.

Identification and Characterization of Acidic Degradation Products of Moxidectin Drug Substance Including Degradation Pathways Using LC, HRMS, and NMR.

Moxidectin is an active pharmaceutical ingredient (API) extensively used in various drug products within the pharmaceutical and animal health sectors. Despite its widespread use, the analytical methods prescribed by the United States Pharmacopeia (USP) and European Pharmacopoeia (EP, Ph. Eur.) exhibit significant limitations. These methods fail to adequately separate key impurities of (23Z)-moxidectin (EP impurity L) and 3,4-epoxy-moxidectin, potentially affecting the quality control, purity assessment, and safety of moxidectin-containing products. The objective was to develop and validate an alternative, improved stability-indicating HPLC method for the identification, assay, and quantification of related substances in the moxidectin drug substance, along with the analysis of its degradation pathways. High-Resolution Mass Spectrometry (HRMS) and Nuclear Magnetic Resonance (NMR) were employed to comprehensively examine moxidectin and its two degradation products under specified acidic conditions. The degradation products were isolated and identified using a range of analytical techniques, including HRMS, NMR, and other relevant methods. The epoxy derivative of moxidectin (RRT = 1.2) was not identified under the studied acidic degradation conditions. HRMS data indicated that the degradant at RRT = 1.2 is an isomer of moxidectin, as it exhibited an identical molecular ion. Detailed NMR studies on moxidectin and its impurity at RRT-1.2 revealed differences in carbon and proton chemical shifts at positions C-22 and C-24, strongly supporting the identification of the structure as an oxime geometric isomer of moxidectin, ie, (23Z)-moxidectin. The findings revealed specific degradation products formed under acidic conditions, offering valuable insights into the chemical transformations of moxidectin. This information is crucial for assessing the drug's stability profile and ensuring the quality and safety of moxidectin-containing products. The HPLC method developed in this study significantly improves upon existing USP/EP methods with regard to a separation of key impurities of (23Z)-moxidectin and 3,4-epoxy-moxidectin, offering robust performance for routine analysis of bulk moxidectin API batches and stability samples in quality control (QC) laboratories.

The effects of coating type and drying temperature on the physicochemical properties of the mixture of lemongrass and apple powdered drinks

Fresh beverages from fruits and herbal plants that contain antioxidants are able to enhance the immunity of the human body. However, such fresh beverage products generally have a short shelf life. As an alternative, the products must be converted into powdered drinks. Coating materials are thus needed to avoid the loss of antioxidant compounds during the drying process. This study aimed to scrutinize the effects of coating type and drying temperature on the quality of lemongrass and Malang apple powdered drinks. The study employed a completely randomized design (CRD) with two factors and two replications. The first factor was the coating type with 3 levels (maltodextrin, dextrin, gum arabic) and the second factor was the drying temperature with 3 levels (40℃, 45℃, 50℃). The data were analyzed using Analysis of variance one-way (ANOVA) test and Duncan's further test if the treatment was significantly different. The results showed that the type of coating significantly affected the parameters of stability, dissolution time, ash content, vitamin C, and antioxidants. Meanwhile, the drying time significantly affected the parameters of stability, dissolution time, water content, ash content, vitamin C, and antioxidants. There was an interaction between the coating type and drying time that affected the bulk density, stability, dissolution time, ash content, vitamin C, and antioxidants. The best result based on the high content of antioxidants was obtained on the dextrin coating type with a drying temperature of 45℃. Product characteristics included a solubility of 0.96 seconds, a bulk density of 0.58 g/mL, a stability of 89.19%, a water content of 2.38%, an ash content of 1.21%, a vitamin C content of 70.22%, an antioxidant inhibition percentage of 50.97%, an IC50 content of 1.29, and a water activity of 0.50.

Optimized Cycling Stability of Single-Crystalline Na0.67Ni0.33Mn0.67O2 Cathode Material via Molten Salt Synthesis for Advanced Sodium-Ion Battery Applications

Recent advancements have highlighted the P2-layered Na0.67Ni0.33Mn0.67O2 (NNMO) cathode material as a leading candidate for next-generation sodium-ion batteries due to its superior specific capacity. Traditional solid-state synthesis methods, while straightforward and scalable, struggle with challenges such as achieving homogeneous atomic-level elemental distribution and mitigating the formation of intermediate phases during powder mixing. In contrast, the molten salt synthesis method offers a controllable and efficient alternative for producing uniform materials with varied chemical compositions and structures. In this study, we utilize sodium chloride as the molten salt flux, with Na2CO3, NiO, and Mn2O3 as reactants, to synthesize single-crystal MS-NNMO. This method yields an NNMO with an initial reversible capacity of 90.6 mAh g−1 at 0.1C across a voltage range of 2.0-4.2 V, demonstrating 88.5% capacity retention after 100 cycles. Long-term stability is further evidenced by an 83.9% capacity retention after 300 cycles at 1C. In full cell tests, MS-NNMO paired with a hard carbon anode shows 90.3% capacity retention after 200 cycles at 1C. Additionally, MS-NNMO exhibits exceptional bulk stability, with no impurity peaks detected after 1 hour of water exposure, underscoring its superior air stability. This work validates the molten salt method as an effective and scalable process for producing high-performance sodium-ion battery cathodes.

Integrated optimization design with inherent element behaviors for bulk and surface stability towards 4.7 V LiCoO2 cathode

LiCoO2 (LCO) cathode with higher energy density can be harvested through raising its upper cut-off voltage to 4.7 V (vs. Li+/Li). However, such high-voltage operation exacerbates the bulk and surface instability of LCO, which is responsible for its rapid capacity decay at high voltages. Consequently, to address these issues, an integrated optimization design is reasonably proposed, which involves Mg/F/PO43- cooperative modulation for LCO (LCO-MFP) based on the inherent behaviors of these elements. Specifically, our theoretical calculations reveal the distinct distribution of Mg/F/PO43- (Mg pillaring, F doping and PO43- coating), which is rooted in their innate occupancy propensity. Consistent with our theoretical results, it is experimentally discerned that Mg and F atoms prefer to enter Li layer and O framework of LCO, respectively, whereas PO43- gravitates towards enrichment on the surface, thereby stabilizing bulk structure, hampering the lattice O/Co evolution and enhancing surface stability. The resulting integrated optimized LCO-MFP cathode can achieve an excellent capacity retention of 81.0 % at 4.7 V after 200 cycles. This integrated optimization design is anticipated to pave the way for selecting appropriate modification elements with their intrinsic properties for high-voltage LCO cathode.

Challenges and Modification Strategies on High-Voltage Layered Oxide Cathode for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) have attracted great attention due to their advantages on resource abundance, cost and safety. Layered oxide cathodes (LOCs) of SIBs possess high theoretical capacity, facile synthesis and low cost, and are promising candidates for large scale energy storage application. Increasing operating voltage is an effective strategy to achieve higher specific capacity and also high energy density of SIBs. However, at high operating voltages, LOCs will undergo a series of phase transitions in bulk phase, leading to huge change of volume and layer spacings accompanied by severe lattice stress and cracking formation. Degeneration of surface also occurs between LOCs and electrolytes, resulting in sustained growth of cathode electrolyte interphase (CEI) and release of O2 and CO2. These induce structural destruction and electrochemical performance degradation in high voltage regions. Recently, many strategies have been proposed to improve electrochemical performance of LOCs under high voltages, including bulk element doping, structural design, surface coating and gradient doping. This review describes pivotal challenges and occurrence mechanisms at high voltages, and summarizes strategies to improve stability of bulk and surface. Viewpoints will be provided to promote development of high energy density SIBs.

Stabilization of single crystal LiNi0.90Mn0.05Co0.05O2 via ZrO2 dual-functional coating enables superior performance for solid-state lithium battery

Chlorine-rich argyrodites with ultrafast Li-ion conductivities exhibits great potential as solid electrolytes for all-solid-state lithium batteries. However, the poor interfacial stability and slow ion dynamics between Li5.5PS4.5Cl1.5 (Cl1.5) and high nickel layered cathode hinder the achievement of superior battery performances. Here, the prepared ZrO2 coating film was found to perform two functions: enhancing the bulk and interfacial stability of single crystal LiNi0.90Mn0.05Co0.05O2 (NCM911) towards sulfide, and facilitating Li-ion transport rates across the interface. A Li2ZrO3 phase with fast Li-ion diffusion rate generates during cycling and further improve the layered-structure integrity of NCM911 and interfacial stability toward the Cl1.5 electrolyte, which are due to the reduction of lattice oxygen release from NCM911 and the isolation of direct contact between the two materials. As a result, these effects enable superior electrochemical performances for the ZrO2-coated NCM911 than the bare sample in Cl1.5-based all-solid-state lithium batteries at varying C-rates and different operating temperatures. It delivers high initial discharge capacities of 156.6 mAh g−1 at 2C and retains 86.0 % of its capacity after 1000 cycles at room temperature, and displays an initial discharge capacity of 172.6 mAh g−1 at 0.5C under 60 °C and 142.4 mAh g−1 at 0.1C under –20 °C, respectively. This dual-functional surface modification strategy provides guidelines to stabilize high-nickel cathode in sulfide-based all-solid-state lithium batteries.

Size-dependent anatase to rutile phase transition under acoustic shocked conditions – A case study of TiO2 bulk and nanoparticles

In the present work, we attempt to explore the size-dependent structural stability of bulk (0.28 µm) and nano-sized (25 nm) anatase TiO2 particles under acoustic shocked conditions. Based on the observed X-ray diffractometric, Raman spectroscopic and transmission electron microscopic results with respect to the number of shock pulses, at the 90-shocked condition, the nano-size particles undergo the anatase to the rutile phase transition, whereas the bulk size TiO2 particles remain to be in the anatase phase. From the comprehensive assessment, it is demonstrated that the bulk TiO2 samples have higher structural stability compared to the nano-size samples. The nano-sized anatase-TiO2particles have values of lower thermal conductivity compared to the bulk-sized particles such that the value of lower thermal conductivity is a prominent crucial factor in initiating the dynamic recrystallization which results in the anatase-to-rutile phase transition. Based on the observed present experimental results and previous reports, it has been authenticated that, while increasing the particle size from nano-scale to micro-scale, the critical shock number for the anatase to rutile phase transition is significantly increased.

Interface Stability and Reaction Mechanisms of Li3YCl5Br with High-Voltage Cathodes and Li Metal Anode: Insights from Ab Initio Simulations.

Recent advancements in battery technology emphasize the critical role of solid electrolytes in enhancing the performance and safety of next-generation batteries. In this study, we investigate the interface stability and reaction mechanisms of Li3YCl5Br, a promising halide-based solid electrolyte, in contact with high-voltage Ni-Mn-Co (NMC) cathodes and a Li metal anode using ab initio molecular dynamics simulations. Our findings reveal that Li3YCl5Br reacts with charged NMC cathodes. This reaction involves changes in the oxidation states of Br- anions in Li3YCl5Br and d-element cations in NMC, as well as the diffusion of Li ions from the solid electrolyte to the cathode to maintain charge balance. The reaction is confined to the interface, suggesting bulk stability. Conversely, the Li/Li3YCl5Br interface exhibits significant instability, with a chemical reaction that results in substantial structural changes and the formation of LiCl and LiBr at the solid electrolyte surface and metallic Y at the Li anode surface. These insights provide valuable information for optimizing interfacial design, aiming at improving the performance and reliability of all-solid-state batteries using halide solid electrolytes.

Density functional investigation of the heterogeneous nucleation of graphite on divalent metal oxides and sulfides

Controlling the nucleation of graphite during solidification of spheroidal and lamellar graphite irons is achieved through minor additions of certain active elements such as Mg, Ca, Sr, Ba and Mn. In the present work, interfaces of graphite with alkaline earth oxides, sulfides and MnS are investigated by density functional simulations of model structures where interfacial strain has been optimized by controlling the twisting angle between the two materials. The bulk stabilities, surface energies and interfacial energies between the nucleant phases, graphite and iron are calculated. A new graphite nucleation model for estimating undercooling based on interfacial energies is proposed. It is found that CaS is the most potent nucleant particle in spheroidal graphite iron and MnS in lamellar graphite iron. The main driver of nucleation potency is found to be of chemical nature rather than related to lattice misfit.

Effect of carbonation curing on the characterization and properties of steel slag-based cementitious materials

Steel slag (SS)-based cementitious materials usually exhibit poor bulk stability, poor early activity and low mechanical strength, which greatly limits the consumption of SS in construction materials. Carbonation curing can not only control volume expansion but also improve the mechanical properties and durability of SS-based cementitious materials. First, the physicochemical properties of the SS were summarized. Then, the reaction mechanism of carbonation curing was analyzed. Next, the mineral composition, microstructure, morphology and CO2 uptake of the SS-based materials during carbonation curing were discussed, and the effects of carbonation curing on the mechanical properties, volume stability and durability of the SS-based materials were investigated. Finally, some suggestions for the application of carbonation curing in SS-based materials were given. The development and application of carbonation curing in SS-based materials can achieve the large-scale utilization of SS in cementitious materials and the effective reduction of CO2 emissions.

The Utilization of Carbonated Steel Slag as a Supplementary Cementitious Material in Cement.

Carbon emission reduction and steel slag (SS) treatment are challenges in the steel industry. The accelerated carbonation of SS and carbonated steel slag (CSS) as a supplementary cementitious material (SCM) in cement can achieve both large-scale utilization of SS and CO2 emission reduction, which is conducive to low-carbon sustainable development. This paper presents the utilization status of CSS. The accelerated carbonation route and its effects on the properties of CSS are described. The carbonation reaction of SS leads to a decrease in the average density, an increase in the specific surface area, a refinement of the pore structure, and the precipitation of different forms of calcium carbonate on the CSS surface. Carbonation can increase the specific surface area of CSS by about 24-80%. The literature review revealed that the CO2 uptake of CSS is 2-27 g/100 g SS. The effects of using CSS as an SCM in cement on the mechanical properties, workability, volume stability, durability, environmental performance, hydration kinetics, and microstructure of the materials are also analyzed and evaluated. Under certain conditions, CSS has a positive effect on cement hydration, which can improve the mechanical properties, workability, bulk stability, and sulfate resistance of SS cement mortar. Meanwhile, SS carbonation inhibits the leaching of heavy metal ions from the solid matrix. The application of CSS mainly focuses on material strength, with less attention being given to durability and environmental performance. The challenges and prospects for the large-scale utilization of CSS in the cement and concrete industry are described.

Orthogonal Electrochemical Stability of Bulk and Surface in Lead Halide Perovskite Thin Films and Nanocrystals.

Lead halide perovskites have attracted significant attention for their wide-ranging applications in optoelectronic devices. A ubiquitous element in these applications is that charging of the perovskite is involved, which can trigger electrochemical degradation reactions. Understanding the underlying factors governing these degradation processes is crucial for improving the stability of perovskite-based devices. For bulk semiconductors, the electrochemical decomposition potentials depend on the stabilization of atoms in the lattice-a parameter linked to the material's solubility. For perovskite nanocrystals (NCs), electrochemical surface reactions are strongly influenced by the binding equilibrium of passivating ligands. Here, we report a spectro-electrochemical study on CsPbBr3 NCs and bulk thin films in contact with various electrolytes, aimed at understanding the factors that control cathodic degradation. These measurements reveal that the cathodic decomposition of NCs is primarily determined by the solubility of surface ligands, with diminished cathodic degradation for NCs in high-polarity electrolyte solvents where ligand solubilities are lower. However, the solubility of the surface ligands and bulk lattice of NCs are orthogonal, such that no electrolyte could be identified where both the surface and bulk are stabilized against cathodic decomposition. This poses inherent challenges for electrochemical applications: (i) The electrochemical stability window of CsPbBr3 NCs is constrained by the reduction potential of dissolved Pb2+ complexes, and (ii) cathodic decomposition occurs well before the conduction band can be populated with electrons. Our findings provide insights to enhance the electrochemical stability of perovskite thin films and NCs, emphasizing the importance of a combined selection of surface passivation and electrolyte.

Investigation of thermodynamical stability and generation of large half-metallic gap along with optical properties in N-doped YHfO3 (YHO) (Y = Ca, Sr, and Ba) perovskite materials by first principle calculations

Considerable energy gap (Eg) in insulating channel, high spin-filtering, significant mean free path, and high magnetic transition temperature (TC) escalate half-metallic (HM) ferromagnetic (FM) materials very enticing for spintronic applications. Herein, ab-initio calculations have been executed comprehensively to inquest the structural, thermodynamical, electronic, magnetic, and optical properties of pure as well as nitrogen (N)-doped YHfO3 (YHO) (Y = Ca/Sr/Ba) materials with one N atom added at one of the oxygen (O) site. First, the thermodynamical stability of both bulk and doped YHO systems has been examined by estimating the formation enthalpies (ΔHf) by Convex Hull analysis, which confirms the practical realization of these materials on experimental grounds. Moreover, mechanical stability of these systems is affirmed by estimating the necessary elastic constants and respective parameters. Strikingly, all doped systems possess complete (100%) splitting in spin↑ and spin↓ channels at Fermi level and depict HM FM character with significant Eg of 3.31, 3.49, and 3.24 eV in spin↓ channels for CaHO (CHO), SrHO (SHO), and BaHO (BHO) systems, respectively. It is also found that N 2p orbitals are totally responsible for the emergence of metatallicity and magnetic character in all these doped structures. Moreover, the ground state long range FM stability between two added N atoms in doped systems is affirmed by computing the difference of total energies of FM and anti-ferromagnetic (AFM) spin ordering (ΔE) along with estimated TC at different distances. Lastly, it is found that N-doped systems have a lower optical energy loss than pristine YHO systems in the incident photon energy range of 0-50 eV. Hence, the present study proposes that an unconventional doping approach with intrinsically non-magnetic element in a variety of YHO perovskite systems could be a useful method to alter their various physical properties and forecast their potential applications in the development of novel spintronic and optoelectronic devices.

Stability in Photoluminescence and Photovoltaic Properties of Formamidinium Lead Iodide Quantum Dots

Formamidinium lead iodide (FAPI) thin films in the perovskite crystalline phase have piqued interest for single-junction solar cells due to their optimal bandgap, long photocarrier lifetime, and intrinsic structural stability. However, trap states on the surface and within the lattice impede the performance and stability of FAPI bulk crystalline film cells. Strategies such as film crystallization, deposition optimization, precursor engineering, and interface property tailoring aim to overcome these limitations. One approach involves forming FAPI quantum dots (QDs). By reducing the size, we achieve better quality and stable alpha-phase FAPI on a nanometer scale. In this contribution, we report synthesizing of alpha-phase FAPI QDs with a mean size distribution of 20 nm. These QDs exhibit a narrow photoluminescence emission peak at 1.61 eV and higher absolute quantum yields ranging from 70% to 86%. Compared to bulk FAPI with a 1.54 eV gap, a blue shift is observed due to the quantum confinement effect.However, achieving degradation-free perovskite solar cells under prolonged light soaking remains a challenge. Furthermore, we investigate the stability of FAPI bulk and QDS films in a humid chamber and after exposure to AM1.5G light in a humid setting (RH ~ 30%, T ~ 28°C). Our approach allows us to form homogeneously dispersed films of quantum dots with thicknesses of several hundred nanometers. These films are studied for photoluminescence and photovoltaic properties. Prototype solar cells incorporating synthesized FAPI QDs showed a power conversion efficiency of around 8%. These findings indicate considerably more stability in photoluminescence and photovoltaic properties of FAPI QDs for enhanced light-soaking stability compared to bulk FAPI films.

Kraft lignin-based polyurethanes: Bulk properties, stability and adhesion to native aluminum surfaces

Lignin as a byproduct from pulp and paper manufacturing has been extensively investigated as raw material for polymer developments. Although, fundamental topics related to the adhesion mechanisms of lignin-based reactive polyurethanes (LPU) still remain unclear. In this work, LPU thin films on native aluminum surface were prepared and characterized. Diluted in THF, employed as the solvent, reactive mixtures of 4,4′-methylene diphenyl isocyanate (4,4′-MDI) and the soluble fraction of three lignins (liquid hydroxypropylated Kraft lignin and two powder Kraft lignins with different pH) were used for LPU thin film deposition via spin coating on aluminum (PVD layer on silicon wafer). The resulting film thickness ranged from 8 nm to several micrometers. The chemical state of the three LPU compositions was assessed in bulk by infrared attenuated total reflectance (IR-ATR) and in the thin films by infrared external reflection absorption spectroscopy (IR-ERAS). Binding energies of 4,4′-methylene diphenyl diisocyanate with aliphatic and aromatic hydroxyl groups were estimated using Density Functional Theory (DFT) simulations. Thus, besides the elucidation of the bulk chemical state of LPUs, the relation to adhesion and stability of LPUs to a native aluminum surface was evaluated. In addition, film topography and homogeneity were monitored by SFM. All lignin types form uniform and homogeneous films. Results revealed a higher consumption of isocyanate groups (NCO) in the formulation with the alkaline Kraft lignin than with the acid one, despite its lower hydroxyl content. A gradient of unreacted NCO was observed in LPU thin films obtained with the powder Kraft lignin types. Residual NCO is also found in thicker films, while the thinnest films did not contain unreacted NCO anymore, indicating the activating effect of the native aluminum surface on LPU formation.

Ce-substituted P2-type layered cathode with interfacial/ bulk stability for sodium ion batteries

Addressing a changing energy environment, sodium-ion batteries (SIBs) have emerged as one of the most potentially applicable energy resources in the world. Nevertheless, its further application is hindered owing to high degree of interfacial degradation and structural changes, which caused rapid capacity fading. Herein, a novel Ce modified P2-type layered structure cathode material Na0.67Mn0.8Co0.17Ce0.03O2 @ CeO2 is introduced, the stability of cell is improved by simultaneous bulk doping and surface coating in one scalable step. The doping of Ce4+ increases sodium ion transport rate by shrinking transition metal layer ions and expanding Na layer spacing. Irreversible phase transition can be mitigated from the stronger the bond energy between TM and O, which is conducive to the decrease in the Mn3+/Mn4+ ratio, and suppression of the Jahn−Teller distortion. Besides, the doping of larger radius Ce4+ extends the internal paths of crystal structure, which decreases the barrier of Na+, correspondingly, the Na+ diffusion rate was increased. Meanwhile, the CeO2 coating layer effectively inhibits parasitic reactions on the surface and improves the stability of the interface. Which display excellent capacity with a remarkable retention of 86.9 % after 100 cycles at 0.5 C and outstanding discharge rate performance of 87 mA h g−1 at 20 C. This study provides a simple process to concurrently stabilize the bulk structure and interface for the future application for sodium-ion batteries.

The role of nanoparticle–surfactant interactions in air-stabilized foams used for improving oil recovery

Foam flooding, an emerging tertiary oil recovery technique, demonstrates efficacy as a conformance control method in enhanced oil recovery. Conformance control mitigates injected displacement fluid channeling and bypassing, improving macroscopic sweep efficiency. Generated foamed films preferentially enter high permeability zones, diverting subsequent injection into unswept lower permeability regions. Nanoparticle-reinforced foams exhibit consistent bulk stability and effective residual oil mobilization. This work utilizes dynamic foam analysis to probe the synergistic effects of zinc oxide nanoparticles and anionic surfactant on foam generation and persistence. Bulk and local scale foam stability is evaluated under various potassium chloride concentrations. Optimal foam stability occurs near the critical micelle concentration of the surfactant at 2,500 ppm. Increasing electrolyte concentration within a fixed surfactant formulation decreases foam stability due to salt-induced micellar swelling. An optimized electrolyte and nanoparticles with a surfactant combination produce high-quality foam with increased bubble density per unit area. Micellar swelling by nanoparticle adsorption inhibits lamellae thinning and liquid drainage. Enhanced foam properties improve microscopic displacement efficiency and mobility control in foam-assisted oil recovery. Oil recovery is increased by approximately 22% compared to conventional waterflooding.

Effective strategy for alleviation of oil contamination in marine via the superhydrophobic biochar: Performances, mechanisms and environmental recalcitrance

The performance of layered double hydroxides (LDH)-biochar composite on alleviating oil spill pollution is poorly understood. A superhydrophobic biochar (NCY) was synthesized from the pristine wood chips biochar (WCB) after the surface deposition of NiCo-LDH (NCB) and hydrophobic modification with stearate. The oil removal potential of the designed biochars was investigated via the diesel oil/crude oil adsorption experiments and the environmental recalcitrance evaluation. The compared characterization results revealed that NiCo-LDH was successfully deposited onto biochar matrix via the electrostatic attraction and pore filling effect, which facilitated a special flower-like hierarchical architecture rough surface for biochar and hinder the multi-layer stacking of LDH. Benefit from the constructed hierarchical architecture, the occupancy of oxygen-containing functional groups and hydrophobic modification of stearate, the water contact angle of NCY (156°) was remarkably larger than NCB (117°) and WCB (50.1°), which exhibit a superhydrophobic. The maximum diesel oil sorption capacities of biochars increased from 3.28 g/g in WCB to 5.64 g/g in NCB and 11.6 g/g in NCY, as well as the maximum crude oil sorption capacities of biochars showed a similar trend (WCB: 4.64 g/g, NCB: 8.74 g/g, NCY: 18.6 g/g). Accordingly, NCY showed higher oil adsorption capacity than NCB and WCB mainly due to the enhanced hydrophobic forces and the π-π electron donor-acceptor interaction resulted from lower amount of O-containing functional groups and superhydrophobic surface wettability. Furthermore, the application of LDH remarkably improved the environmental recalcitrance of biochar (resist to the chemical oxidation and thermal decomposition in marine) due to the coating of NiCo-LDH could enhance the bulk stability of biochar and increase the liable carbon content in biochar. This study proved that the application of NiCo-LDH and stearate could be an effective approach for improve the oil pollution remediation capacity and the environmental recalcitrance of biochar.