Impaired Mechanisms Research Articles

Quantitative assessment of hardened leather artifact deterioration using infrared spectroscopy

This article describes a quantitative assessment method proposed to quickly identify the degree of deterioration of hardened leather artefacts. We used three techniques to artificially age samples, namely, dry-heat ageing (DH), UV-ageing (UV), and alkali-thermal ageing (AT). The deterioration mechanisms were studied via thermogravimetry/derivative thermogravimetry (TG/DTG) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Combined with amide III band deconvolution and second derivative fitting, we constructed a method for assessing the degree of deterioration by the relative content of random coils (referred to as R) in the secondary structure of the protein. The results show that with increasing ageing time, the macrostructures and microstructures of the leather changed to varying degrees. This study elucidates the differential behaviour of vegetable-tanned leather collagen under oxidative and hydrolytic mechanisms. Based on the deterioration characteristics and fitting results, we divided the hardened leather into the following three levels. Mild deterioration: 0 ≤ R ≤ 5%; leather with reduced pores and slight dryness and hardness but with a stable collagen structure; if the β-sheet content is ≥ 68% at this point, the leather may be recrosslinked by ultraviolet irradiation. Moderate deterioration: 6 ≤ R ≤ 25%; partial hydrogen bond breaking in leather, loosening of the collagen–tan matrix, dry and hard curling of the leather surface, and fibre cementation. Severe deterioration: R ≥ 40%, β-sheet ≤ 24%, and the α-helix is higher; surface reflection, severe macroscopic deformation and embrittlement, and the breakdown and gelatinization of the three-stranded helical structure of leather proteins. The quantitative analysis method was suitable for studying the deterioration mechanisms and assessing the degree of deterioration in Heishanling leather artefacts, which also provides a new practical scheme for assessing the degree of hardened leather.Graphical

A Review of Atmospheric Deterioration and Sustainable Conservation of Calcareous Stone in Historical Buildings and Monuments

Calcareous stones, such as marble and limestone, have been widely used in ancient architecture due to their durability, abundance, and ease of extraction and workability. However, their chemical nature renders them vulnerable to atmospheric pollutants. With industrialization and socio-economic growth, air pollution has severely impacted built heritage, including numerous historical buildings and monuments, particularly under changing climate and environmental conditions. Various forms of degradation, such as acid corrosion, mineral crystallization, and black crusts, are widespread and typically driven by atmospheric pollutants like sulfur dioxide (SO2), nitrogen oxides (NOX), ozone (O3), and particulates (PM), which accelerate the deterioration of stone surfaces. To develop sustainable mitigation strategies, it is essential to gain an in-depth understanding of these deterioration mechanisms and current technological advancements. This paper first reviews the influencing factors and underlying mechanisms of atmospheric deterioration of calcareous stones. Subsequently, it discusses the advantages and limitations of traditional and advanced conservation and restoration techniques at the micro-level, as well as pollution management strategies that can be adopted. Finally, the challenges of research in this field are highlighted, and directions for the sustainable conservation of calcareous stones are proposed.

Study on the effect of water on the shear behavior and microstructure of red mudstone

Red mudstone has significant hydrophilicity, that is hard at low water contents and soft and unstable at high water contents, and understanding the whole range of water content on the shear behavior of red mudstone is critical for evaluating red beds landslide stability. However, the deterioration mechanism of red mudstone in the process of gradual humidification is not clear in the whole range of water content. In this study, a series of mechanical and microscopic tests were carried out in the whole range of water content. A mechanical behavior prediction model for the entire process under the coupling of initial damage and load damage was constructed. The results show that the deterioration of shear strength, elastic modulus and strength parameters conforms to the “logistic model” curve with the increase of water content in the whole range of water content. In addition, the water sensitivity of cohesion was higher than the internal friction angle, and it gradually stabilized as water content increased. The weakening mechanism of the mechanical strength in the accelerated decline stage is the initiation and propagation of microcracks caused by mineral expansion, which leads to the corresponding shear behavior. Finally, the constructed damage model can be transformed into different yield conditions through parameter changes. The introduction of coupling damage enables the model to more accurately describe and predict the accelerated attenuation stage of red mudstone in the process of gradual humidification in the whole range of water content.

Assessment of the efficiency of distinct surface treatments to mitigate ASR-induced development

Over the years, various coating materials have been used to mitigate/rehabilitate concrete once alkali-silica reaction (ASR) takes place. Although promising results are demonstrated, their efficiency is compromised by the progression of ASR and crack formation. Recently, new coatings with higher penetrability and enhanced self-healing properties have shown good performance against distinct durability problems in concrete, yet their behaviour under ASR development is unknown. This research appraises the ability of hydrophilic self-healing coating (CA) mixtures to mitigate concrete deterioration caused by ASR in its initial, moderate and advanced phases. Their efficiency is multi-level assessed, and comparisons with other systems (e.g., silane/siloxane, rigid-coating and lithium-based) are also performed. Results indicate that the surface treatments with CA changed ASR kinetics while not altering the ASR mechanism of deterioration. Finally, qualitative charts are provided to help select different types of surface treatments and the most appropriate “timing” for their application.

Freeze-thaw resistance and deterioration mechanism of alkali-activated filling grouts prepared from full industrial solid wastes for tunnels

To promote the application of the proposed alkali-activated grout (AAG) prepared from full solid wastes in cold-zone tunnel projects located at high altitudes and latitudes, it is imperative to fully recognise its endurance to the repeated freezing and thawing in specific service scenarios. For this purpose, two groups of representative AAG were selected as subjects for this study, and a typical OPC-based grout was chosen as the control group. Freeze-thaw cycle tests were carried out on grout samples after 28 days of standard curing using the slow-freeze method to simulate the harsh service environment in cold regions. The deterioration impact of freeze-thaw cycling on the grout samples were evaluated by monitoring the changes in visual appearance, mass loss, mechanical strength, and damage coefficient after 20, 40, 60 and 80 freeze-thaw cycles. Furthermore, the deterioration mechanism of various grout samples under the action of freeze-thaw cycling was revealed by multi-technique characterization methods including X-ray diffraction (XRD), scanning electron microscope (SEM), and mercury intrusion porosimetry (MIP). The results show that at the same number of freeze-thaw cycles, the surface deterioration, mass loss and strength damage of AAG were obviously better than that of the OPC-based grout, suggesting that AAG exhibited greater resistance to freezing and thawing than the OPC-based grout. The mass loss ratio increased with the increase of the number of freeze-thaw cycles, following a roughly power function pattern. The deterioration in the flexural strength of grout samples caused by freeze-thaw cycles was more severe than the deterioration in their compressive strength. The gel products of AAG were mainly C-A-S-H and N-A-S-H, which showed stronger resistance to freeze-thaw damage than the gel products of the OPC-based grout, C-S-H and portlandite. Compared with the OPC-based grout, AAG samples possessed a denser microstructure with lower porosity and a smaller proportion of large-sized harmful pores, which was not favourable for the pore water holding and migration of during freeze-thaw cycling and the development of osmotic and frost heave stresses, thus providing better resistance to freezing and thawing. A variety of macroscopic characterisations and microstructural tests have demonstrated the good durability of AAG against the freeze-thaw cycles, which can serve as a scientific foundation for its future engineering uses.

Strength Deterioration Mechanism of Interface between Soil–Rock Mixture and Concrete with Different Degrees of Roughness under Freeze–Thaw Cycles

Strength Deterioration Mechanism of Interface between Soil–Rock Mixture and Concrete with Different Degrees of Roughness under Freeze–Thaw Cycles

Durability of concrete containing carbonated recycled aggregates: A comprehensive review

The utilisation of carbonated recycled aggregates in concrete has been increasingly considered as an effective strategy for CO2 sequestration in the built environment and enhancement of concrete sustainability. Following up a pervious review on the role of carbonated recycled concrete aggregates in the mechanical properties of concrete, this paper presents a comprehensive review on the effects of carbonation treatment on the chemical compositions and physical properties of recycled concrete aggregates, as well as the role of carbonated recycled concrete aggregates in microstructure and durability-related properties including volume deformation, transport properties, chemical resistance, freeze-thaw resistance and fire resistance of concrete. A special focus is placed on the relationship between microstructure and durability-related properties of carbonated recycled aggregate concrete considering the effects of pre-treatment method, replacement level, curing age, water-to-binder ratio and quality of the original aggregates. The insights into the deterioration mechanism and strategies for improving the durability of carbonated recycled aggregate concrete are provided. This review summarises the recent advances in the field, followed by a discussion on the remaining challenges and opportunities for future research.

Integrating widely targeted and oxylipin-targeted lipidomics unravels lipid characteristic evolution and oxidation markers in walnuts during deterioration

The susceptibility of walnut lipids to deterioration constitutes challenges for industry development, and the oxylipins formed during this process remain to be explored. This study employed lipidomics to reveal the dynamic evolution of lipid characteristics and identify oxidation markers from oxylipins in walnuts during accelerated storage. Glycerophospholipid (GP) content continuously declined in the initial and severe deterioration stages. The accumulation of diglycerides and partial lysophospholipids characterized initial deterioration. Triglycerides were prone to direct oxidation, while GPs tended to be first hydrolyzed. GP metabolism especially phosphatidylethanolamine degradation triggered walnut deterioration. Moreover, ten oxylipins derived from linoleic acids were identified in walnuts. Trans-EKODE-(E)-Ib, 13-HODE, 9-HODE, and 9(S),12(S),13(S)-TriHOME were screened as oxidation markers. The cellular structure exhibited the cell membrane and oil body membrane rupture during deterioration. Potential mechanisms of lipid deterioration were proposed, providing a scientific basis and guidance in optimizing quality control strategies and assessing practical deterioration degrees of walnuts.

Effect of hydro-chemical corrosion on mechanical properties of red sandstone under uniaxial and triaxial compression

The degradation of mechanical characteristics of sandstone, a common engineering material in acid environment, is directly related to the project service life forecast. In order to investigate the influence of water–rock interaction on the mechanical properties of red sandstone, a series of uniaxial and triaxial compression tests were conducted on sandstone immersed in solutions of different pH values and immersion times. Moreover, the effects of acid chemical corrosion on the microscopic structure of the sandstone were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) tests. A chemical damage strength model was then formulated within the theoretical framework of chemical reaction kinetics theory. The results indicate that the different hydro-chemical solutions have a significant deterioration effect on the sandstone. In immersion tests, the water–rock reaction of sandstone is essentially completed after 30 days of immersion. With increasing immersion time, the uniaxial compressive strength of sandstone immersed in neutral and weakly acidic saline solutions shows an initial rapid decrease followed by a slow increase, while sandstone immersed in distilled water and strongly acidic solutions shows varying degrees of decrease over time. High confining pressure weakens the corrosion effect of the solutions on the sandstone, particularly, the neutral solution. In the triaxial compression tests, strong acid has a great corrosion effect on sandstone. The average peak strength of sandstone immersed in pH2, pH4, pH7, and distilled water decreased by 30.2%, 28.7%, 25.1%, and 22.8%, respectively. The model considers calcium precipitation not only reflects the change in pH value of the immersion solution with time but also effectively predicts the strength of sandstone immersed in different solutions. The results deepen our understanding of the deterioration mechanism of silicon-based porous rock under different chemical solutions and would be of importance for the long-term stability analysis of rock engineering in complex groundwater environments.

Research on deterioration mechanism of graded gravel in high-speed railway subgrade layer based on machine vision

This study aims to investigate the macro-micro deterioration mechanism of graded gravel under cyclic loading, which is of great significance in revealing the generation mechanism of high-speed railway subgrade defects in service and guiding the subgrade reinforcement. Initially, a precise-rapid quantification method for particle shape based on machine vision was established. To further improve the existing traditional semantic segmentation model (U-Net), a novel semantic segmentation model named VGG16-UNet-CA was established, which incorporated the U-Net, VGG16 model, Bilinear interpolation, and Coordinate attention (CA). Moreover, the high-precision binary images obtained by the established model were imported into Open Source Computer Vision Library (OpenCV) to calculate the particle shape indicators rapidly. Additionally, the cyclic loading tests were carried out to characterize the macro deterioration of graded gravel based on the mechanical indicator dynamic stiffness K, and the key factor of deterioration was explored through the established machine vision method. Finally, biaxial compression models with different deterioration degree were established by Discrete Element Method (DEM) to explore the micro deterioration mechanism. It was found that the segmentation accuracy indicators F1-score, Mean Pixel Accuracy (MPA) and Mean Intersection over Union (MIoU) of VGG16-UNet-CA were 98.56 %, 97.89 % and 98.01 %, which were higher than U-Net, SegNet, PSPNet, and DeepLabv3+. During the cyclic loading, the changes of the equivalent particle diameter De and slenderness ratio Ei of coarse particles in three filler groups were not significant, while the average values of roundness Rc increased by 28 %, 31 % and 25 %, indicating that the coarse particle abrasion was the key factor of deterioration. In the DEM simulation, with the increase of Rc, the mechanical strength of graded gravel decreased and the micro indicators (e.g., sliding rate, strong force chains, and anisotropy parameter an) inside the fillers gradually decreased, while the particle rotation continuously increased. Consequently, the interlocking ability of coarse particles decreased, leading to the bearing capacity and structural stability of particle skeleton reduced. This study not only provides a novel approach to investigate the deterioration mechanism of graded gravel under cyclic loading, which contributes to revealing the generation mechanism of high-speed railway subgrade defects in service, but also provides theoretical support for subgrade reinforcement.

Analysis of Enzyme Interference Factors During Storage of Millet Based on Machine Learning

The color of millet beige is one of the important factors related to the quality of millet. As people's living standards continue to improve, consumers and the millet industry market are increasingly demanding quality. The fading problem of millet during storage has seriously affected the edible quality and commercial value of millet. However, there are few reports on the mechanism of millet storage deterioration so far. This paper combines machine learning algorithms to systematically study the relationship between lipoxygenase and the color of millet fading from the physiological and molecular levels. Moreover, this paper uses multiple sets of variables to conduct experimental research to explore the molecular mechanism of millet fading phenomenon, which not only provides a theoretical basis for delaying millet aging and ensuring millet storage quality, but also has important significance for the breeding of millet beige quality.

Constitutive model and deterioration mechanisms of uniaxial compressive behavior for calcium aluminate cement-based UHPC under simulated fire temperatures

Conventional ordinary Portland cement (OPC)-based UHPC is vulnerable to explosive spalling and its performance deteriorates significantly under fire temperatures. In this context, the calcium aluminate cement-based UHPC (AC-UHPC) was prepared by combining the calcium aluminate cement (CAC), recycled brick powder (RBP) and refractory steel fiber (RSF) according to the theory of maximum particle packing in this study, aiming at developing a green, economical and high-temperature resistant CAC-based material. This paper mainly investigated the influence of RSF and exposure temperature on the compressive properties of AC-UHPC, and revealed the degradation mechanism at elevated temperature through the analysis of apparent characteristics and microstructure. The results showed that the compressive strength and strain reached the maximum at 400 °C and 1000 °C, which were increased by 27.57–38.34 % and 2.89–3.44 times respectively compared with that at ambient temperature, while the initial elastic modulus gradually decreased. In the range of 20–400 °C, the phase transformation of hydration products mainly determined the strength of AC-UHPC. above 800 °C, the high temperature stability of RSFs has a significant impact on the residual compressive strength and deformation. At 1200 °C, the compressive strength decreased to 38.81–45.32 % and 24.88–30.41 % of the ambient temperature, respectively. Based on the test results, the prediction equations of compressive strength, peak strain and elastic modulus were proposed, and the empirical constitutive model and damage constitutive model of AC-UHPC considering exposure temperature and RSF volume fraction under uniaxial compression were established. This research offers valuable insights for the design and potential enhancement of green, economical and high temperature resistant CAC-based composites to improve the performance under fire conditions.

Study of microstructural evolution during operation of electrically connected components and analysis of failure mechanism

Abstract As a key current-carrying structure of high-voltage bushings, the reliability of electrical connection components is crucial to the safe and stable operation of power equipment. To obtain the microstructural evolution of electrical connection components with different deterioration states, CUD strap contactors were deteriorated in different ways, and electron backscatter diffraction technique was used to test the microstructure of strap contactors with different deterioration states. The results showed that compared to the unused contactors, the contact resistance of the contactors under the combined effect of friction and high temperature increased 203.12 times and was in a failed state. During the process from unused state to wear deterioration, high temperature deterioration, and then to eventual failure of the contactors, the average grain size gradually grows from 8.15 μm to 25 μm, the dislocation density gradually decreases from 2.38 × 1014 m−2 to 1.04 × 1014 m−2, and there are a significant proportion of the recrystallized organization. These changes are detrimental to the mechanical properties of the contactors. In addition, the distribution of grain boundaries in the contact area proves the occurrence of over-temperature phenomenon in this area, which will accelerate the deterioration of the contactors and eventually lead to the failure of the component. The relevant conclusions can provide a theoretical basis for the design of electrical connection structure of strap contacts as well as the study of deterioration mechanism.

Formulation and Implicit Numerical Integration of a Kinematic Hardening Model for Unsaturated Soils

ABSTRACTCurrently, our understanding of material‐scale deterioration resulting from meteorologically induced variations in pore water pressure and its significant impact on infrastructure slopes is limited. To bridge this knowledge gap, we have developed an extended kinematic hardening constitutive model for unsaturated soils that refines our understanding of weather‐driven deterioration mechanisms in heterogeneous clay soils. This model has the capability of predicting the irrecoverable degradation of strength and stiffness that has been shown to occur when soils undergo wetting and drying cycles. The model is equipped with a fully coupled and hysteretic water retention curve and a hysteretic loading–collapse curve and has the capability to predict the irrecoverable degradation of strength and stiffness that occurs during cyclic loading of soils. Here, we employ a fully implicit stress integration technique and give particular emphasis to deriving a consistent tangent operator, which includes the linearisation of the retention curve. The proposed algorithm is evaluated for efficiency and performance by simulating various stress and strain‐driven triaxial paths, and the accuracy of the integration technique is evaluated through the use of convergence curves.

The association between metabolite profiles and impaired bone microstructure in adult growth hormone deficient rats

BackgroundAdult growth hormone deficiency (AGHD) is associated with an increased risk of fractures and impaired bone microstructure. Understanding the metabolic changes accompanying bone deterioration in AGHD might provide insights into mechanisms behind molecular changes and develop new biomarkers or nutritional strategies for bone destruction. Our study aimed to investigate the association between altered metabolite patterns and impaired bone microstructure in adult rats with growth hormone deficiency.MethodsThirty seven-week-aged adult Lewis dwarf homozygous (dw/dw) rats (five females and five males), and adult Lewis dwarf heterozygous (dw/ +) rats (five females and five males) rats were compared. Micro-computed tomography (Micro-CT) was used to examine the bone's microstructure. Hematoxylin and eosin (H&E) staining were used to quantify the histological characteristics. Liquid chromatography-mass spectrometry untargeted serum metabolomic analysis was applied in the study. ELISA was used to measure serum bone turnover markers and IGF-1 levels.ResultsAdult dw/dw rats exhibited great reductions in trabecular volume bone density (Tb.vBMD), bone volume/total volume (BV/TV), and cortical thickness (Ct. Th) compared with adult dw/ + rats (all p values < 0.05), indicating significant impairment in bone microstructure. The serum metabolite profiles revealed substantial differences between the dw/dw rats and dw/ + rats. A total of 134 differential metabolites in positive ion mode and 49 differential metabolites in negative mode were identified. Five metabolites, including Lysophosphatidylcholine(LPC) 20:3, LPC22:6, LPC22:4, cortisol and histamine levels were upregulated in dw/dw rats. The steroid hormone biosynthesis and bile secretion pathways were the main perturbed metabolic pathways. There were significant associations between differential metabolites and the impaired bone microstructure parameters, indicating that the selected metabolites might serve as potential biomarkers for deteriorated bone microstructure in AGHD.ConclusionAdult dw/dw rats exhibit impaired bone microstructure and distinct serum metabolic profiles, and the altered metabolites were significantly associated with bone microstructure destruction. This provides a new insight into understanding the mechanism of bone deterioration in AGHD patients from a metabolic perspective.

Crack Development and Electrical Degradation in Chromium Thin Films Under Tensile Stress on PET Substrates

The mechanical and electrical deterioration of chromium (Cr) thin films sputtered onto polyethylene terephthalate (PET) substrates under tensile strain was studied. Understanding mechanical and electrical stability due to imposed strain is particularly important for device reliability, as the demand for flexible electronic devices increases. Cr thin films, widely spread across the field of electronic and sensor applications, face crack propagation with electrical degradation with tensile stress that can seriously compromise the performance. Accordingly, this study offers new findings on how Cr film thickness might influence crack formation and electrical resistance differently and also the general guidelines for flexible electronic component design with respect to long-term durability. Electrical resistances were measured while mechanically stretching 100- and 200 nm thin sheets. The study focused on crack development and propagation mechanisms in both film thicknesses and their effects on percentage change in electrical resistance (PCER). Scanning electronic microscopy (SEM) was used to characterize surface morphology and observe cracks as the strain rose. Early crack formation in 100 nm Cr films led to rapid PCER increases due to quick crack propagation and fast electrical degradation. Thicker 200 nm films, however, showed a more gradual PCER rise with fewer but deeper cracks, indicating a regulated strain response. Unlike the sharp PCER spike in 100 nm films, 200 nm samples were more variable, with three out of four showing a slight PCER decrease at the end, hinting at partial crack repair or conductive realignment before full failure. These results underscore the role of layer thickness in managing crack propagation and electrical stability, relevant for flexible electronics and strain sensors. This paper is aligned with the ninth goal of the United Nations Sustainable Development Goals, specifically Target 9.5: Enhance Research and Upgrade Industrial Technologies.

4D-label free based comparative proteomics revealed the responsive mechanisms of quality deterioration driven by spore release in shiitake mushrooms

Label-free quantitative proteomics profiles combined with biochemical analysis were applied in three spore release stages to investigate the proteome responses related to spore release inducing the quality loss of mushrooms. During the spore release, the mushrooms softened, and malondialdehyde (MDA) and total free amino acids accumulated, especially bitter amino acids. Among the 2720 identified proteins, aminoacyl-tRNA biosynthesis, oxidative phosphorylation, and other glycan degradation pathways were primarily implicated. ATP-binding cassette (ABC) transporters and purine metabolism stimulated energy consumption in the second stage, which could be responsible for the spore release. Moreover, aminoacyl-tRNA ligase and ribosomal proteins were identified as hub proteins, actively expressed, and significantly associated with quality traits. The hub proteins might play a dominant role in mediating the quality deterioration triggered by the spore release in shiitake mushrooms. The results expand the understanding of the molecular mechanisms underlying the response to spore release in shiitake mushrooms.

Combination transcriptomic and metabolomic reveal deterioration of the blue honeysuckle (Lonicera caerulea L.) fruit and candidate genes regulating metabolism in the post-harvest stage

Blue honeysuckle, a new berry with high nutritional value, possesses typical berry postharvest properties, including extreme perishability, rapid quality loss, and high sensitivity to microbial infections. At present, the underlying mechanisms of postharvest quality deterioration, senescence, and low-temperature regulation remain largely unknown. This study aimed to elucidate the metabolic shifts and genetic regulation underlying the preservation or deterioration of blue honeysuckle during storage at room temperature (25 °C) and low temperature (4 °C). Storage at 4 °C inhibited fruit decay and preserved better visual quality, weight, firmness, and total soluble solid and acid contents. We identified 24 key differentially accumulated metabolites that specifically changed during the qualitative shift at room temperature and were effectively regulated by 4 °C. Commonly associated metabolites, sorbitol, succinic acid, malic acid, naringenin, pinobanksin, and taxifolin, characterize the deterioration of blue honeysuckle. These metabolites were integrated with transcriptomic data for weighted correlation network analysis (WGCNA). Regulatory networks were used for the identification of key genes and transcription factors (TFs) influencing sugar, organic acid, flavonoid, and phenolic acid metabolism during storage. The findings provide insight into metabolic regulation and the improvement of flavor in postharvest blue honeysuckle fruit.

Study on the decay laws and deterioration mechanism of mechanical properties of cement-stabilized gravel under water-heat-salt coupled conditions

A new type of asphalt pavement disease, known as arch expansion, has appeared in the saline soil regions of Northwest China. The emergence, as well as the evolution of the disease, is strongly related to the distribution of sulfate. However, the decay of Cement-stabilized gravel (CSG) mechanical properties is closely related to the onset and development of arch expansion. The relationship between CSG mechanical strength and salinity in the arch expansion area is analyzed based on field investigations to systematically study the mechanical property degradation law and mechanism of CSG. The mechanical strength and deterioration patterns of CSG with different coupling conditions were investigated. The mineral composition and micromorphology of the erosion products were analyzed. The results show that the mechanical properties of CSG in the area of the arch deteriorate more than those in the regular section. The mechanical strength of the specimens initially containing salt and partially immersed in salt solution decayed most severely. In terms of the deterioration mechanism of mechanical strength of CSG, the water-heat-salt erosion process is also divided into two parts, including the formation stage of gypsum and ettringite, the stage of C-S-H decomposition and thaumasite formation, respectively. The degradation mechanism of CSG is a combination of physical and chemical erosion.

The electrochemical performance deterioration mechanism of LiNi0.83Mn0.05Co0.12O2 in aqueous slurry and a mitigation strategy

Integrating high-nickel layered oxide cathodes with aqueous slurry electrode preparation routes holds the potential to simultaneously meet the demands for high energy density and low-cost production of lithium-ion batteries. However, the influence of dual exposure to air and liquid water as well as the heating treatment during aqueous slurry electrode processing on the high-nickel layered oxide electrode is yet to be understood. In this study, we systematically investigate the structural evolution and electrochemical behaviors when LiNi0.83Mn0.05Co0.12O2 (NMC83) is subjected to aqueous slurry processing. It was observed that the crystal structure near the surface of NMC83 is partially reconstructed to contain a mixture of rock-salt and layered phases when exposed to water, leading to the deteriorated rate capability of the NMC83 electrodes. This partial surface reconstruction layer completely converts into a pure rock-salt phase upon cycling, accompanied by the release of O2, Ni leaching, catalyzed decomposition of the electrolyte, and the formation of a thick cathode electrolyte interphase layer. The byproducts of the electrolyte and dissolved Ni could shuttle to the Li metal side, causing a crosstalk effect that results in a thick and unstable solid electrolyte interphase layer on the Li surface. These in combination severely undermined the cycling stability of the NMC83 electrodes obtained from the aqueous slurry. A mitigation strategy using molecular self-assembly technique was demonstrated to enhance the surface stability of water-treated NMC83. Our findings offer new insights for tailoring ambient environment stability and aqueous slurry processability for ultra-high nickel layered oxide and other water-sensitive cathode materials.