Volume Expansion Research Articles

Macro‐meso damage cracking and energy dissipation of rock‐backfill composites: Effect of cyclic disturbance frequency

AbstractThis work aims to reveal the effect of cyclic disturbance frequency, i.e., 0.01, 0.1, 0.5, and 1.0 Hz, on damage cracking and energy dissipation characteristics of rock‐backfill composite structure specimens. Testing results show that fatigue volumetric strain and secant modulus increase with increasing disturbance frequency; low‐frequency disturbance leads to an earlier volume expansion. In addition, the strain energy density increases with increasing disturbance frequency. Most of the energy are dissipated for the specimen under high‐frequency disturbance. Finally, computed tomography scanning reveals the influence of disturbance frequency on failure modes; tensile‐splitting failure and shear failure are likely to occur at the surrounding rock subjected to high‐ and low‐ frequency disturbances. Low‐frequency‐disturbed stress seems easily to stimulate cracks at the rock‐backfill interfaces and the backfill; the backfill can absorb much more energy than high‐frequency circumstances. It is suggested that the role of backfill in energy absorption, contact support, and stress isolation is disturbance frequency dependent.

Experimental investigation on macroscopic fracture and microstructural evolution of granite under high-temperature steam action

This study conducted simulated experiments on the thermal fracturing of granite under non-uniform stress conditions using the method of injecting high-temperature and high-pressure steam. Additionally, a comprehensive investigation was carried out on the thermal fracturing characteristics of granite after steam treatment, as well as the distribution patterns of cracks. The results show that: Firstly, the process of fracturing granite using high-temperature and high-pressure steam as a medium can be divided into five stages. The threshold temperature for thermal fracturing of granite is 260 ℃, at which point a large number of cracks develop or form interconnected networks. Secondly, under high-temperature conditions, the tensile strength of granite is greatly reduced. The temperature at which brittle fracture occurs in granite during the experiment was found to be 427 ℃ at a steam pressure of 10.6 MPa. Thirdly, under the influence of high-temperature and high-pressure steam, granite not only generates primary cracks along the direction perpendicular to the minimum principal stress but also produces a certain number of secondary cracks in other directions. The crack propagation direction can be determined from the velocity and permeability distribution maps of fractured granite. Finally, the fracture surface of granite exhibits significant brittle characteristics. The fracture morphology mainly includes transgranular and intergranular fractures. In the experiment, the fracture surface also showed fragmented and fatigue-induced fracture features. The fractal dimension of micro-morphological features can be used to assess the extent of thermal fracturing at different locations on the fracture surface. Through macroscopic fracturing experiments and comprehensive analysis of theory, wave velocity, and micro-morphology, the study obtained relevant crack propagation patterns and the formation of cracks in different directions. This is of practical significance in the formation of interconnected spatial fracture networks, thereby helping to increase the thermal exchange surface area of artificial reservoirs and improve the efficiency of geothermal exploitation.

Radiomics of Intrahepatic Cholangiocarcinoma and Peritumoral Tissue Predicts Postoperative Survival: Development of a CT-Based Clinical-Radiomic Model.

For many tumors, radiomics provided a relevant prognostic contribution. This study tested whether the computed tomography (CT)-based textural features of intrahepatic cholangiocarcinoma (ICC) and peritumoral tissue improve the prediction of survival after resection compared with the standard clinical indices. All consecutive patients affected by ICC who underwent hepatectomy at six high-volume centers (2009-2019) were considered for the study. The arterial and portal phases of CT performed fewer than 60days before surgery were analyzed. A manual segmentation of the tumor was performed (Tumor-VOI). A 5-mm volume expansion then was applied to identify the peritumoral tissue (Margin-VOI). The study enrolled 215 patients. After a median follow-up period of 28months, the overall survival (OS) rate was 57.0%, and the progression-free survival (PFS) rate was 34.9% at 3years. The clinical predictive model of OS had a C-index of 0.681. The addition of radiomic features led to a progressive improvement of performances (C-index of 0.71, including the portal Tumor-VOI, C-index of 0.752 including the portal Tumor- and Margin-VOI, C-index of 0.764, including all VOIs of the portal and arterial phases). The latter model combined clinical variables (CA19-9 and tumor pattern), tumor indices (density, homogeneity), margin data (kurtosis, compacity, shape), and GLRLM indices. The model had performance equivalent to that of the postoperative clinical model including the pathology data (C-index of 0.765). The same results were observed for PFS. The radiomics of ICC and peritumoral tissue extracted from preoperative CT improves the prediction of survival. Both the portal and arterial phases should be considered. Radiomic and clinical data are complementary and achieve a preoperative estimation of prognosis equivalent to that achieved in the postoperative setting.

Addressing fiscal uncertainty: Proposing policy pathways for enhancing economic growth and fertility rates in South Korea

This study investigates the critical role of fiscal uncertainty in driving economic growth in South Korea and explores the potential implications for the nation's long-standing low fertility challenge. Utilizing country-year data and advanced measures disaggregating economic policy uncertainty into dimensions like fiscal, monetary, and trade uncertainty, the analysis reveals a strong negative association between fiscal uncertainty and GDP growth rates over the past three decades. Periods of heightened fiscal volatility, characterized by unpredictable government spending, tax policies, and overall economic instability, consistently preceded declines in economic growth. Moreover, the findings indicate that fiscal uncertainty moderates the relationship between economic expansion and fertility rates. While GDP growth generally improves conditions favorable for childbearing by raising living standards, the positive impact on fertility diminishes as fiscal uncertainty increases. Strikingly, at sufficiently high levels of uncertainty, economic growth fails to boost fertility rates, underscoring the crucial role of fiscal stability in reaping the full benefits of growth. These insights highlight the importance of reducing fiscal uncertainty through strategies like implementing tax and spending "calendarization" systems and adopting long-term policy planning horizons. By promoting fiscal predictability and fostering an environment conducive to sustained economic expansion, policymakers can indirectly create conditions that support higher fertility rates by alleviating household aversion to uncertainty. While focused on economic factors, this research acknowledges the multifaceted nature of fertility decisions and calls for a holistic policy approach combined with further causal investigations using micro-level data and experimental designs. Ultimately, prioritizing fiscal stability and addressing fiscal uncertainty present a critical pathway towards stimulating economic growth and potentially revitalizing fertility rates in South Korea and similar developed nations confronting demographic challenges.

Effect of heat treatment on microcracking behaviors and Mode-I fracture characteristics of granite: An experimental and numerical investigation

Combining thermal stimulation and tensile fracture induced by cold water injection can synergistically enhance hydraulic fracturing, improving geothermal reservoir connectivity. To investigate the heat effect on the Mode-I fracture characteristics of granite, notched semi-circular bend (SCB) granite specimens were prepared and heat-treated at five temperatures ranging from 25 to 600 ℃. Mineralogical analysis and three-point bending tests were performed on the SCB specimens, and a grain-based model (GBM) incorporating four types of mineral particles was developed. The model was simulated for heat treatment and Mode-I loading and then validated against experimental results. The behavior and evolution of intra- and intergranular microcracks in the SCB specimens during heating, cooling, and mechanical loading were analyzed. Moreover, the fracture surface morphology and microcracking mechanisms observed in the SCB specimens at different heat-treatment temperatures were discussed. The results reveal a nonlinear trend in the Mode-I fracture toughness of the SCB specimens, initially increasing and then decreasing with heat-treatment temperature. The number of thermally induced cracks escalates with increasing heat-treatment temperature, predominantly as intergranular tensile cracks, followed by intragranular tensile cracks. Under Mode-I loading, the SCB specimens heat-treated below 450 ℃ predominantly exhibit intergranular cracks, while intragranular tensile cracks become more prevalent at 600 ℃. Thermally induced cracks can alter the propagation direction and path of mechanically induced cracks, causing macrocracks to deviate from the initial straight propagation path. Scanning electron microscope (SEM) analysis illustrates that at 300 ℃ and above, the fracture surface morphology becomes more fragmented and longer microcracks appear.

Electrochemically Dealloying Engineering toward Integrated Monolithic Electrodes with Superior Electrochemical Li-Storage Properties.

Integrated monolithic electrodes (IMEs) free of inactive components demonstrate great potential in boosting energy-power densities and cycling life of lithium-ion batteries. However, their practical applications are significantly limited by low active substance loading (< 4.0mgcm-2 and 1.0gcm-3), complicated manufacturing process, and high fabrication cost. Herein, employing industrial Cu-Mn alloy foil as a precursor, a simple neutral salt solution-mediated electrochemical dealloying strategy is proposed to address such problems. The resultant Cu-Mn IMEs achieve not only a significantly larger active material loading due to the in situ generated Cu2O and MnOx (ca. 16.0mgcm-2 and 1.78gcm-3), simultaneously fast transport of ions and electrons due to the well-formed nanoporous structure and built-in Cu current collector, but also high structural stability due to the interconnected ligaments and suitable free space to relieve the volume expansion upon lithiation. As a result, they demonstrate remarkable performances including large specific capacities (> 5.7mAhcm-2), remarkable pseudocapacitive effect despite the battery-type constitutes, long cycling life, and good working condition in a lithium-ion full cell. This study sheds new light on the further development of IMEs, enriches the existing dealloying techniques, and builds a bridge between the two.

Investigating the expansion behavior of silicon nanoparticles and the effects of electrolyte composition using a graphene liquid cell

Understanding the volume expansion behavior of Si anodes and their interaction with electrolyte environments is crucial for developing high-performance lithium-ion batteries (LIBs). This study utilizes a graphene liquid cell for in situ imaging to systematically investigate the volume expansion and etching behavior of Si anode nanoparticles in different electrolyte environments. Comparative experiments on Si@C core-shell nanoparticles assess their volume expansion dynamics. The findings reveal significant variation in the expansion rate of nano Si depending on the electrolyte environment, with chemical etching observed under specific conditions. Conversely, Si@C core-shell structures show mitigated expansion due to the confinement effect of the carbon matrix. Battery performance experiments validate these results, demonstrating the excellent cycling stability of Si@C anodes. Various coating agents are explored to optimize Si@C structures, with dopamine thin layer coating exhibiting the best cycling stability. This study offers fundamental insights into Si anode expansion, electrolyte effects, and carbon coating impacts, advancing LIB technology.

Experimental and theoretical studies on cobalt ruthenium phosphate structure optimization towards supercapacitor application

Recent studies have given indications that nanoarchitectured binary transition metal phosphates can act as potential supercapacitor (SC) electrode materials due to their exceptional energy storage capacity and remarkable electrochemical stability. However, the highly amorphous nature or broad X-ray diffraction peaks of metal phosphates put a limit on the structural optimization of these materials. We demonstrate a combined experimental and theoretical study leading to an optimized cobalt-ruthenium phosphate (CRP) structure for high-performance SC application. The material structure was optimized by detailed density functional theory (DFT) calculations, including the Bader charge analysis, DOS, and PDOS, revealed the lattice and volume expansion, reduced band gap, and improved conductivity of the cobalt phosphate lattice by including ruthenium in the cobalt phosphate. These predictions are verified with experimental band gap and high-resolution transmission electron microscope plane image indexing. Further, the CRP was developed by potentiostatic deposition onto the carbon cloth substrate. The flexible CRP electrode exhibited a high specific capacitance of 1258 F g−1 (943.5C g−1) in the aqueous 2 M KOH electrolyte. The asymmetric SC device (CRP//activated carbon) has exhibited an excellent specific energy of ∼59 Wh kg−1 at a specific power of ∼751 W kg−1.

Core-Double-Shell TiO2@Fe3O4@C Microspheres with Enhanced Cycling Performance as Anode Materials for Lithium-Ion Batteries.

Due to the volume expansion effect during charge and discharge processes, the application of transition metal oxide anode materials in lithium-ion batteries is limited. Composite materials and carbon coating are often considered feasible improvement methods. In this study, three types of TiO2@Fe3O4@C microspheres with a core-double-shell structure, namely TFCS (TiO2@Fe3O4@C with 0.0119 g PVP), TFCM (TiO2@Fe3O4@C with 0.0238 g PVP), and TFCL (TiO2@Fe3O4@C with 0.0476 g PVP), were prepared using PVP (polyvinylpyrrolidone) as the carbon source through homogeneous precipitation and high-temperature carbonization methods. After 500 cycles at a current density of 2 C, the specific capacities of these three microspheres are all higher than that of TiO2@Fe2O3 with significantly improved cycling stability. Among them, TFCM exhibits the highest specific capacity of 328.3 mAh·g-1, which was attributed to the amorphous carbon layer effectively mitigating the capacity decay caused by the volume expansion of iron oxide during charge and discharge processes. Additionally, the carbon coating layer enhances the electrical conductivity of the TiO2@Fe3O4@C materials, thereby improving their rate performance. Within the range of 100 to 1600 mA·g-1, the capacity retention rates for TiO2@Fe2O3, TFCS, TFCM, and TFCL are 27.2%, 35.2%, 35.9%, and 36.9%, respectively. This study provides insights into the development of new lithium-ion battery anode materials based on Ti and Fe oxides with the abundance and environmental friendliness of iron, titanium, and carbon resources in TiO2@Fe3O4@C microsphere anode materials, making this strategy potentially applicable.

Self-consuming expansion stress construct piezoelectric field to accelerate anion for SiO/PbZr0.52Ti0.48O3 with persistent lithium storage performance

The high theoretical specific capacity and suitable working potential of silicon oxides (SiOx) making it one of the most promising candidates for the next generation of lithium-ion battery anode materials. However, the large-scale application of SiOx in lithium-ion battery anodes is hampered by the huge volume change (>200 %) during cycling process. This experiment adopts a method which is completely contrary to the traditional modification method——composite with piezoelectric materials to take advantage of this expansion. During the lithiation process, the significant volume expansion stress of SiO is transformed into a driving force by PbZr0.52Ti0.48O3 (PZT) particles that enhances the transport of Li+. The polarization of PZT particles occurs as a result of the consumption of mechanical stress caused by the expansion of SiO, leading to the generation of a piezoelectric potential. Since then, the volume expansion stress of SiO when deintercalating lithium is converted into a potential difference, which can promote the migration of Li+. This process not only reduces the volume expansion of SiO, but also promotes the mobility of Li+. The SiO/PZT anode shows an admirable cycle performance: The discharge capacity is 825.4 mA h g−1, and the capacity retention ratio is reach up to 92.5 % (200 mA g−1, 200 cycles). These findings illuminate the surface coupling approach employed to regulate the behavior of interfacial Li+ kinetics, while simultaneously enhancing the structural stability of alloy-based anodes. This research will undoubtedly capture the attention of researchers engaged in the study of multifunctional interface design for electrochemical systems.

Thermal and chemical expansion of layered oxygen-deficient double perovskites

Layered oxygen-deficient double perovskites (ODP) based on the rare-earth elements (REE), barium and 3d-metals (Fe, Co, Cu etc.) are characterized by high values of electrical conductivity and high electrochemical activity in oxygen reduction reaction, and are considered as prospective cathode materials for intermediate-temperature solid oxide fuel cells (SOFC) on the base of proton- and oxygen-ion conducting solid electrolytes (SE). Effective cathode materials should be thermomechanically compatible with materials of SE, which tаkes place when the values of their thermal expansion coefficients (TEC) are close to each other. Due to this the study of thermal expansion of ODP as well as the isotation of different contributions in it (thermal, chemical, spin etc.), is of considerable interest. In this work using dilatometric method the thermal expansion of NdBa1–xSrxFeCo0,5Cu0,5O6−δ (0.0 ≤ х ≤ 1.0) (NBSFCC) ODP was studied using dilatometric method. It was established that the values of average linear thermal expansion coefficient (LTEC) (α) of the samples sharply increased from (15.1–16.2) · 10–6 K–1 at Т &lt; 630–920 K to (18.9–23.5) 10–6 K–1 at Т &gt; 630–920 K due to the evolution of weaklybonded oxygen from the samples. Values of α in the low-temperature region increase with increasing of values of their oxygen nonstoichiometry index (δ), and in the high-temperature one increase with the x increasing due to the increment of chemical contribution in the samples expansion. Based of the results of dilatometry, thermogravimetry, and iodometry, the thermal and chemical contributions in the expansion оn NBSFCC were isolated, and the effect of crystal structure, cationic and anionic composition of NBSFCC ODP on the values of their thermal and linear chemical expansion coefficient (LCEC, αδ ) was investigated. It was found, that LCEC values of the samples sharply increased from (8.6–11.8) · 10–3 at (х &lt; 0.5) to (12.6–15.8) · 10–3 at (х &gt; 0.5) when transition from ordered tetragonal (х &lt; 0.5) to disordered cubic (х &gt; 0.5) phase took place. It was shown, that dependences of LTEC and LCEC of NBSFCC phases on their crystal structure and chemical compositions obtained in this work are in good accordance with the analogous dependences determined earlier for the ODP of other types.

Pressure‐Induced Dense and Robust Ge Architecture for Superior Volumetric Lithium Storage

AbstractThe germanium (Ge) anode attains wide attention in lithium‐ion batteries because of its high theoretical volumetric capacity (8646 mAh cm−3). However, the huge volume expansion (≈230%) results in its poor electrochemical performances. The strategies reported in the literature to solve the issue often cause a low packing density, lowering the volumetric capacity. Here, a pressure‐induced route is proposed to fabricate a Ge architecture, in which nano‐sized Ge (≈15 nm) is encapsulated by robust TiO2 and highly conductive carbon, which offer the advantages of a low stress–strain characteristic, low volume expansion in thickness change, high electrical conductivity (463.2 S m−1), high Li‐ion diffusion coefficient (9.55 × 10−9–8.51 × 10−12 cm2 s−1), and high tapping density (1.79 g cm−3). As a result, the dense architecture obtains outstanding volumetric capacities of 3559.8 mAh cm−3 at 0.1 A g−1 and 2628.2 mAh cm−3 at 20 A g−1, along with excellent cycling life over 5000 cycles at 10 A g−1. Remarkably, the full cell achieves a high volumetric energy density of 1760.1 Wh L−1, along with impressive fast‐charging performances and long cycling life. This work provides a new synthesis strategy and deep insight into the design of high‐volumetric capacity alloy‐based lithium‐ion‐battery anodes.

Heat expansion and zeta

Heat expansion and zeta

#2662 Octreotide-LAR in ADPKD patients with very low kidney function: a monocentric real-life experience

Abstract Background and Aims Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease, characterized by development of fluid-filled renal cysts leading to progressive expansion of kidney volume, with decline in kidney function up to end-stage renal disease (ESRD). Octreotide long-acting release (OCT-LAR) is a synthetic somatostatin analogue, which has been shown to reduce kidney and cysts growth and to slow the progression of kidney function decline in ADPKD patients. Although the evidence of the literature supporting the protective effect of the OCT-LAR against progression of the disease in ADPKD patients with both early and later-stages, to date no data are available in ADPKD patients treated with this somatostatin analogue in a real-world clinical setting. In August 2018 OCT-LAR was approved only in Italy for the treatment of ADPKD adult patients with eGFR ranging from 30 to 15 mL/min/1.73 m2 at elevated risk of progression towards ESRD. The present study is aimed to report for the first time the effects on renal function of OCT-LAR in ADPKD patients with severe renal insufficiency (stage 4 CKD) receiving this somatostatin analogue for therapeutic indication in a real-world clinical setting. Method We conducted a retrospective, ADPKD-population-based cohort study using healthcare data from the medical records of patients with ADPKD referred to the Department of Nephrology of University “Federico II” of Naples from November 2018 to April 2023 aimed to analyse within-patient clinical outcomes, including eGFR decline, before and after treatment with OCT-LAR. We include adult ADPKD patients (≥18 years) with GFR (eGFR) between 30 and 15 mL/min/1.73 m2, stably treated from at least 1 years with the regular dose of OCTR-LAR. The primary endpoint was the assessment of eGFR decline from 1 year before the start of the treatment (T-1) to baseline (T0), and after 1 year of therapy with OCT-LAR (T1) in the overall population and in two subgroups of patients with eGFR ≥ or &amp;lt; 25 ml/min/1.73 m2. Results 31 ADPKD patients were analysed (18 with eGFR ≥ 25 and 13 with eGFR &amp;lt; 25). Compared to pre-treatment period, eGFR decline significantly slowed during therapy with OCT-LAR in both eGFR groups (Table 1), while no difference was found between eGFR groups. After the first year of observation, 7 patients required dialysis (all with eGFR &amp;lt;25). Conclusion This is the first study reporting the effects of OCT-LAR on eGFR of ADPKD patients with advanced chronic kidney disease (CKD) in a real-world clinical setting. Our results suggest that, compared the last year of follow-up pre-treatment, OCT-LAR slows eGFR decline after 1 year.

#1816 CA 125 as a surrogate marker for plasma volume in patients with cardiorenal syndrome

Abstract Background and Aims Assessing volume status in heart failure (HF) and end-stage chronic kidney disease (CKD) is challenging. Plasma volume expansion is an early step in the pathophysiology of decompensated HF and an independent risk factor for death and HF hospitalization, and should be addressed early. Evaluating plasma volume, especially its variation with diuretic therapy, can be a useful clinical tool for guiding decongestive therapy. There's a growing need for accurate and simple tools to guide clinician decisions on patient volume management. Cancer antigen 125 (CA125), a glycoprotein produced in mesothelial cells in the pericardium, pleura, or peritoneum, is primarily associated with ovarian and gynecological malignancies. Recent studies link CA125 to inflammation and congestion. In acute HF, elevated CA125 is associated with fluid overload indicators like increased central venous and pulmonary wedge pressure. Elevated CA125 in acute HF patients is linked to worse outcomes in death and hospital stay length. Evidence supports CA125-guided therapy in acute HF, but its role in managing chronic volume overload is still uncertain. We aim to assess the relationship between CA125 levels and estimated plasma volume (ePV). Method A retrospective unicentric observational study was conducted between June 2022, and April 17, 2023, at the Renocardiac clinic of a tertiary hospital. Clinical data were extracted from electronic patient records. CKD staging was determined following the Kidney Disease Improving Global Outcomes (KDIGO) classification. ePV was calculated using the Kaplan-Hakim formula. CA125 and ePV were assessed for the same patient in 2 different visits and their variation was calculated. The correlation between CA125 and ePV, as well as CA125 and ePV variation, was evaluated using Spearman's rank correlation coefficient for bivariate analysis, conducted with IBM SPSS®. Results This study comprised 65 patients, totaling 124 hospital visits. The patient demographic was 67.7% male, with a mean age of 76.4 (±12.47) years. In terms of CKD staging, 48.5% were classified as KDIGO 5, 40.6% as KDIGO 4, 9.4% as KDIGO 3, and 1.5% as KDIGO 2. HF etiology distribution included 59% ischemic, 9.8% hypertensive, 6.5% valvular, and 24.5% other causes. The mean ejection fraction was 37.35 (±12.36)% and 19% had preserved ejection fraction; 75% of them were treated with prognostic-modifying medication, including SGLT2 inhibitors. This proportion was lower (19%) in patients with reduced ejection fraction, receiving ACE/angiotensin ± neprilysin inhibitor + mineralocorticoid receptor inhibitor + beta-blocker + SGLT2 inhibitor. During the follow-up period, 13 hospitalizations, 1 major adverse cardiovascular event (MACE), and 5 deaths were recorded. The mean CA125 level was 193.98 (±154.55) U/mL, and patients had a mean ePV of 2.41 (±1.19) L. A significant positive correlation was found between CA125 levels and ePV (r = 0.355, p = 0.000). However, there was no significant correlation between the variation of CA125 and ePV levels between visits (p = 0.535). Conclusion This study focuses on a population with limited implementation of disease-modifying therapy due to advanced CKD, complicating the clinical management of volume status, kidney function, potassium levels, and long-term prognosis in both CKD and HF. CA125 shows potential clinical utility as a marker of congestion, aiding clinicians in assessing volume status by correlating with plasma volume. However, this study found no correlation between CA125 variation and changes in plasma volume. The outpatient nature of the studied population, typically euvolemic, may hinder assessing the relationship between CA125 and ePV changes. Future studies with larger sample sizes are essential to clarify this relationship and potentially identify volume-expanded patients early.

Rational design of nitrogen-doping Ti3C2Tx microspheres with enhanced polysulfide catalytic activity for lithium-sulfur batteries

The primary challenges that impede the practical applications of lithium-sulfur batteries are the significant shuttle effect of polysulfides, huge volume expansion, and slow redox kinetics. In this work, three-dimensional nitrogen doping Ti3C2Tx MXenes (3D N-Ti3C2Tx ) were successfully synthesized by spray drying and subsequent annealing, and hydrochloric acid-treated melamine effectively reduces the oxidation of MXenes in these processes. The formation of a unique nanoflower-shaped microsphere endows 3D N-Ti3C2Tx with a significant specific surface area and pore volume. The combination of nitrogen doping and the large specific surface area increased adsorption capacity and catalytic conversion ability for polysulfide intermediates. Consequently, the obtained 3D N-Ti3C2Tx /S cathode exhibited high-capacity retention (578.5 mAh g-1 after 500 cycles at 0.5 C and 462.5 mAh g-1 after 1,000 cycles at 1 C), superior rate performance (651.2 mAh g-1 at 3 C), and excellent long-term cycling performance (capacity fading rate of 0.076% per cycle at 0.5 C and 0.046% per cycle at 1 C). This work expands the potential applications of MXenes for lithium-sulfur batteries.

Recycling of waste silicon powder from the photovoltaic industry into high performance porous Si@void@carbon anodes for Li-ion battery

To enhance the performance of lithium-ion battery anodes, this study leverages recycled diamond wire-cut silicon particles, a byproduct of the photovoltaic sector. These particles undergo purification through acid wash and pyrolysis to eliminate contaminants, thereby serving as potential anode materials. The inherent challenge with silicon involves its significant volumetric expansion during lithiation and delithiation, which hampers its viability for commercial applications. Addressing this, the research introduces a facile approach by synthesizing porous silicon (pSi) via the Ag-assisted chemical etching method. Subsequently, a distinctive yolk-shell porous silicon@void@carbon (pSi@V@C) structure is created using a sacrificial template approach, ensuring the formation of voids between the porous silicon core and the carbon shell. This configuration mitigates the detrimental effects of silicon's volume expansion while enhancing electrical conductivity through the carbon shell. The pSi@V@C composite exhibits promising electrochemical performance, demonstrated by an initial discharge capacity of 1826 mAh g-1 and a Coulombic efficiency of 68.6% at 0.1 A g-1. Remarkably, it maintains a capacity of 821.8 mAh g-1 after 550 cycles at 1 A g-1, with a retention rate of 90.4%.

Research on quantitative analysis method of shale oil reservoir sensitivity based on mineral analysis

Mineral compositions of shale reservoirs are complex and highly influenced by external fluids. At present, there are limited studies on the effect of mineral expansion rate on external fluids, and there is a lack of systematic research on the sensitivity of shale reservoir porosity to external fluids. In this paper, firstly, X-Ray Diffractometer (XRD) experiments were carried out to study the mineral composition of shale reservoirs, revealing the mechanism of shale minerals interacting with acidic/alkaline fluids. Secondly, the sensitivity evaluation experiments of single mineral external fluid immersion were conducted on the main minerals in shale. Finally, a prediction method for the sensitivity of shale reservoir porosity to external fluids (acidic/alkaline fluids, oil slicks) was established. The results show that: (a) Volume expansion of quartz after 48 h of immersion in alkaline fluids at pH = 9 and pH = 11 and the expansion rate is maximum at pH = 9 i.e. 0.16. (b) Volume expansion of chlorite after 48 h immersion in alkaline fluid and maximum expansion at pH = 13 i.e. 0.55. (c) The improvement of total porosity of shale by acid solution is weak. (e) Alkaline solution has a weak damage to the total porosity of shale, and the degree of damage increases and then decreases with the increase of the strength of alkaline solution.

Rational optimization of substituted α‐MnO2 cathode for aqueous zinc‐ion battery

AbstractDensity functional theory (DFT) is utilized to explore the effects of increasing concentrations of vanadium (V) and chromium (Cr) substitution on the discharge of α‐MnO2 cathode in hydrated zinc‐ion batteries (ZIBs). During H+‐intercalation and Zn2+‐intercalation, Cr‐substitution proves to be more effective than V‐substitution in promoting discharge behaviors. Transitioning from Mn0.875Cr0.125O2, Mn0.75Cr0.25O2 to Mn0.625Cr0.375O2 is found to consistently enhance the discharge voltage, along with improved tunnel structure retention and volume expansion suppression. In comparison, the promoting effect of increasing V‐substitution is relatively small at initial discharge stages and leads to degradation at later stages, primarily due to an increased concentration of unstable Mn2+ ion. The superior effect of Cr‐substitution is attributed to the unique atomic and electronic structures of substituted Cr4+ and reduced Cr3+ ions during discharge. These ions serve as active electron acceptors to limit the formation of Mn3+ and Mn2+ ions, and as anchors to stabilize the α‐MnO2 framework and intercalated H+/Zn2+ ions, respectively. Our study highlights fine‐tuning through substitution to enhance the performance of α‐MnO2‐based cathode materials in ZIBs.

Solid-state transformation composite filler: A new strategy to strengthen ceramic/metal joint

Residual stress is the main hindrance to achieve a robust ceramic/metal brazed joint. In this study, yttria stabilized zirconia (YSZ) particles was fabricated into solid-state transformation composite filler, which was proposed as a new strategy to strengthen Ti3SiC2/Cu brazed joint. After detailed characterization conducted on YSZ particles and brazed joint, the abnormal expansion properties of YSZ and its strengthening brazed joint mechanism were clarified. The content of Y2O3 in YSZ had significant effects on the phase transformation of ZrO2 from tetragonal to monoclinic. When 3 mol.% Y2O3 was added, the maximum phase transformation occurred at about 500 ◦C, half of brazing temperature, during the cooling process. The phase transformation of ZrO2 effectively released residual stress in the joint, which was induced by both temperature changes and residual stress. The abnormal volume expansion during phase transformation decreased the thermal mismatch of brazed joint further to strengthen brazed joint.