Accelerated Aging Experiments Research Articles

Research on the aging mechanism of polypropylene nonwoven geotextiles under simulated heavy metal aging scenarios

We conducted accelerated aging experiments on two types of polypropylene (PP) nonwoven geotextiles (filament geotextile and staple fiber geotextile), immersing them in five different simulated liquids at temperatures of 25 °C, 55 °C, and 85 °C for 200 days. At 85 °C and a pH of 1, the tensile strength and elongation at break of PP filament materials decreased by 95% and 86%, respectively. The presence of heavy metals(arsenic and cadmium), speeds up the aging process in both types of PP geotextiles. Under identical conditions, these heavy metals can increase the loss of tensile strength in geotextiles by more than 7% in 200 days. Increases in temperature, acidic environment, and heavy metal concentration all contribute to faster aging of these geotextiles. Although filament geotextiles exhibit higher tensile strength and elongation at break, staple fiber geotextiles show a lower rate of tensile strength loss during aging and better maintain their tensile strength in high-temperature acidic conditions. During the aging process, cross-linking and recrystallization occur, both of which control the aging rate and the formation of microplastics.

Assessment of Accelerated Aging Effect of Bio-Oil Fractions Utilizing Ultrahigh-Resolution Mass Spectrometry and k-Means Clustering of van Krevelen Compositional Space.

Bio-oils contain a substantial number of highly oxygenated hydrocarbons, which often exhibit low thermal stability during storage, handling, and refining. The primary objectives of this study are to characterize the hydroxyl group in bio-oil fractions and to investigate the relationship between the type of hydroxyl group and accelerated aging behavior. A bio-oil was fractionated into five solubility-based fractions, classified in two main groups: water-soluble and water-insoluble fractions. These fractions were then subjected to chemoselective reactions to tag molecules containing hydroxyl groups and analyzed by negative-ion electrospray ionization 21 T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The fractions were also subjected to accelerated aging experiments and characterized by FT-ICR MS and bulk viscosity measurements. Extracting insightful information from ultrahigh-resolution data to aid in predicting upgrading methodologies and instability behaviors of bio-oils is challenging due to the complexity of the data. To address this, an unsupervised learning technique, k-means clustering analysis, was used to semiquantify molecular compositions with a close Euclidean distance within the (O/C, H/C) chemical space. The combination of k-means analysis with findings from chemoselective reactions allowed the distinctive hydroxyl functionalities across the samples to be inferred. Our results indicate that the hexane-soluble fraction contained numerous molecules containing primary and secondary alcohols, while the water-soluble fraction displayed diverse groups of oxygenated compounds, clustered near to carbohydrate-like and pyrolytic humin-like materials. Despite its high oxygen content, the water-soluble fraction showed minimal changes in viscosity during aging. In contrast, a significant increase in viscosity was observed in the water-insoluble materials, specifically, the low- and high-molecular-weight lignin fractions (LMWL and HMWL, respectively). Among these two fractions, the HMWL exhibited the highest increase in viscosity after only 4 h of accelerated aging. Our results indicate that this aging behavior is attributed to an increased number of molecular compositions containing phenolic groups. Thus, the chemical compositions within the HMWL are the major contributors to the viscosity changes in the bio-oil under accelerated aging conditions. This highlights the crucial role of oxygen functionality in bio-oil aging, suggesting that a high oxygen content alone does not necessarily correlate with an increase of viscosity. Unlike other bio-oil categorization methods based on constrained molecule locations within the van Krevelen compositional space, k-means clustering can identify patterns within ultrahigh-resolution data inherent to the unique chemical fingerprint of each sample.

Investigating the Differences between the in-Situ Galvanostatic Test and Ex-Situ Fenton Test on Nafion Membranes for PEM Water Electrolysis

Perfluorinated sulfonic acid (PFSA) ionomer membranes (e.g Nafion) are widely employed as the benchmark materials for the electrolyte membranes in PEM water electrolysis (PEMWE). It is broadly acknowledged that the state of health of PFSA membranes is detrimentally impacted by the chemical degradation occurring during operation of PEMWE. The cross-over gases interacting with the catalytic surface lead to the generation of hydrogen peroxide. This compound can undergo homolytic cleavage or, in the presence of ferrous salts, yield reactive oxygen species such as hydroperoxyl (HOO.) and hydroxyl (HO.) radicals. These radicals attack the ionomer subsequently leading to chain scission, unzipping and loss of functional groups and release of HF in the effluent water. However, the degree of degradation differs when exposed to ex-situ conditions compared to real proton exchange membrane (PEM) water electrolysis conditions.This work depicts a methodical investigation of degradation of catalyst coated Nafion membranes (CCM) using a Fenton's accelerated aging experiment and in-situ test. In the Fenton's approach, the durability of Nafion 117 and catalyst coated Nafion membrane with counter ions such as ferrous ions against H2O2 was explored as a degradation factor of polymer electrolyte water electrolyser. CCMs were submerged to a solution containing ferrous ions and peroxide. Accelerated aging experiments were conducted over a period of 3-7 days. An in-situ ageing test has been performed on a MEA with and without the presence of Ferrous ions by applying galvanostatic pulses for 7 days. Experimental confirmation of degradation mechanisms has been obtained by post-mortem analysis of the MEA using microscopy and chemical analysis and mechanical investigation. To quantify the effect of water activity in Nafion and CCM chemical structure on both water diffusion and interfacial transport, pulse field gradient spin echo nuclear magnetic resonance (PFGSE-NMR) technique has been employed. Morphological characteristics before and after aging tests were also investigated. Comparative estimation of the fluoride release rate in case of both in-situ and ex-situ test was also performed. This work offers a comprehensive dataset comparing the performance of degraded membranes both in situ and ex situ.

Multi-scale moisture diffusion modeling and analysis of carbon/Kevlar-fiber hybrid composite laminates under the hygrothermal aging environment

Hybrid fiber reinforced polymer (HFRP) can have more complex micro moisture diffusion process than single fiber composite, owing to diverse hygroscopic properties of dissimilar fibers. Thus, elucidating the multi-scale moisture diffusion mechanism of HFRP through experimental method becomes a challenging endeavor. To this end, a multi-scale moisture diffusion modeling approach is proposed to investigate the moisture diffusion behavior of carbon/Kevlar HFRP under the hygrothermal aging environment. Leveraging Fick's law as a foundation, a combination of multi-scale moisture diffusion model and finite element method is employed. To validate the effectiveness of model, accelerated aging experiments are conducted on HFRP samples with various stacking sequences. By SEM characterization, the surface aging on aged Kevlar fibers and the debonding of aged fiber/matrix interface are conspicuously observed. Based on this model, the moisture diffusion behaviors in different HFRP configurations are simulated and analyzed to reveal the micro-, meso‑ and macro-scale moisture diffusion and resistance mechanisms. Our findings highlight the profound influence of factors such as fiber type, fiber content, fiber placement, hygroscopic properties of constituents, and their synergistic effects on moisture absorption and saturated moisture absorption rates. Finally, the hygroscopic properties of HFRP laminate with different stacking sequences are predicted by multi-scale model. This work endeavor furnishes valuable insights and guidelines for the design and analysis of moisture-resistant HFRP.

Study on the effect of multi-factor compound action on long-term tensile performance of GFRP composite pipe and life prediction analysis

In this work, the glass fiber reinforced plastic (GFRP) composite pipes used as sewerage pipes in oil and gas field environments were studied. The accelerated aging experiments were carried out under the simulated environments of three typical oil field media which including circulating air, simulated produced water and standard simulated oil. Scanning electron microscopy (SEM) was adopted to observe the microscopic morphology of the aged GFRP tubes under the three conditions. The microstructural characteristics of the aged tubes and the evolution process of internal defects were also analyzed and evaluated in combination with micro-CT technology. The attenuation pattern of the hoop tensile strength of the aged pipes was measured via the separation disk method, and the service life prediction was carried out based on the Arrhenius theory with the hoop strength as the life index. The results show that the accumulation of aging time and continuous heat input will aggravate the expansion of internal pores and cause the aggregation of small-volume defects into large-volume defects. Especially in the simulated oil environment, which has the highest sensitivity to defects. The maximum porosity reaching 1.5 % and the maximum volume of individual defects exceeding 106 μm3 after aging for 4000 h at 95 °C. The thermal aging process under the three environmental conditions had similar aging characteristics, and interfacial damage of the glass fibers was observed in all of them. The variability of hydrothermal aging is related to the hydrolytic behavior of the glass fibers, which is associated with the progressive dissolution damage of the SiO2 network in the glass fibers, as well as the breaking of silane bonds. Thus, the hydrothermal environment had the most significant effect on the hoop tensile strength decay. Ultimately, 75 % strength retention was taken as the end-of-life indicator. The predicted service life based on the Arrhenius model for the three environments of thermo-oxygen, hydrothermal and simulated oil were 23.5, 23.1 and 28.5 years at 20 °C, and 12.2, 4.9 and 10.3 years at 40 °C, respectively.

Layered double hydroxides for simultaneous and long-term immobilization of metal(loid)s in soil under simulated aging

Soil contamination by toxic metals and metalloids poses a grave threat to food security and human well-being. Immobilization serves as an effective method for the remediation of soils contaminated by metal(loid)s. Nevertheless, the ability of soil amendments for simultaneous immobilization of cations and oxyanions, and the long-term effectiveness of immobilization need substantial improvements. In this study, we used a series of layered double hydroxides (LDHs), including Mg-Al LDH and Ca-Al LDH fabricated from pure chemicals, and one waste-derived LDH synthesized using granulated ground blast furnace slag (GGBS), for the immobilization of Cu, Zn, As, and Sb in a historically contaminated soil obscured from a mining-affected region. The LDHs were first subjected to iron (Fe) modification to enhance their short-term immobilization performances toward metal(loid)s. Furthermore, the long-term effectiveness of Fe-modified LDHs was examined via two sets of experiments, including column experiments simulating 2-year water leaching, and accelerated aging experiments simulating 100-year proton attack. It was observed that Fe-modified LDHs, either made from pure chemicals or GGBS, demonstrated promising long-term immobilization performances toward metal(loid)s. Results from this study are encouraging for the future use of LDHs for simultaneous and long-term immobilization of metal(loid)s in soil.

Nondestructive and accurate prediction of IGBT junction temperature in wind power converters: based on IDMOA-ELM prediction method

ABSTRACT This study has made significant advancements in predicting junction temperature of IGBTs in wind power converters. An improved dwarf mongoose optimisation algorithm (IDMOA) with superior performance was developed. The IDMOA improves the initial solution quality through Hammersley initialisation, balances global search and local optimisation with nonlinear dynamic decreasing weight factors, and enhances population diversity via differential evolution strategy to avoid local optima. The IDMOA optimizes random parameters of extreme learning machine (ELM), overcoming the limitations of traditional manual parameter setting and constructing a high-precision IDMOA optimised ELM (IDMOA-ELM) model. Simulation results indicate that the IDMOA-ELM excels in predicting the IGBT junction temperature, achieving a low RMSE value of 0.1034 ℃. This significantly surpasses existing technologies and provides robust support for temperature management in wind power converters. Furthermore, to verify the performance of the DMOA-ELM in practical application scenarios, IGBT accelerated ageing experiments were conducted, yielding a comprehensive validation dataset. The high accuracy and effectiveness of the IDMOA-ELM were confirmed through comparative analysis with experimental data, enhancing the credibility of the research. This study achieved non-destructive and high-precision prediction of IGBT junction temperature in wind power converters and significantly improving the reliability of wind power converters.

Aging of a Poly(vinyl acetate)-Based White Glue and Its Durability in Contemporary Artworks.

While extensive research has focused on understanding the degradation mechanisms of Poly(vinyl acetate) (PVAC) paint under different environmental conditions, limited attention has been paid to the long-term stability of PVAC-based white glues, especially when used in artworks. This study investigates the accelerated degradation, under simulated photoaging, and isothermal treatment of a commercial PVAC-based white glue considered representative of this class of materials used in contemporary artworks to predict its durability and assess its behavior in art objects. Through accelerated aging experiments and comparison with natural aging observed in artworks, the study reveals the formation of chromophores and the release of plasticizers as key processes; in particular, the progressive darkening was considered an early indicator of degradation processes, before structural changes could be detected by FTIR or NMR spectroscopies. The plasticizer loss induces an increase in glass transition temperature, from 7 °C to temperatures higher than room temperature, affecting the adhesive's cohesive strength and contributing to the detachment of materials in artworks. The findings underscore the importance of preventive conservation measures to mitigate degradation issues in PVAC-based artworks.

Differentiation of aging properties in different circumferential layers of the polyethylene pipeline

Abstract Polyethylene (PE) pipelines have been widely used as a substitute for steel pipelines in urban natural gas transportation around the world, due to their corrosion resistance, low cost, and good construction performance. As a kind of non-metallic material, PE pipelines age while being used. Currently, the aging status of PE pipelines is not clear and a reliable method to evaluate the aging life of them is necessary to be deeply explored. Due to the different contact with oxygen while using, the aging conditions of the outer, middle, and inner layers are also various. According to the research in this work, the aged PE80 pipelines in accelerated aging experiments were divided into three layers including outer, middle, and inner layers. The aging performance of the three layers has great differences. A comprehensive method for the aging properties of PE80 pipelines should be established while evaluating PE pipelines in service.

A new detection method for the ageing state of composite insulators based on spectral–spatial feature fusion

Composite insulators are integral to the power grid, providing electrical insulation and mechanical support. However, their prolonged exposure to outdoor conditions renders them vulnerable to ageing. This can result in flashovers and economic losses. Hyperspectral imaging (HSI) has been identified as a promising non-contact detection method to effectively assess the microscopic ageing status of these insulators’ surfaces. This study involved conducting artificial accelerated ageing experiments to mimic extended outdoor operational conditions. The static contact angle of ageing silicone rubber samples served as the basis for ageing classification. High-resolution HSIs of samples at various ageing stages were obtained, covering wavelengths from 400 nm to 1040 nm. Singular spectrum analysis was applied to denoise spectral and spatial domains, eliminating environmental and equipment-related noise effectively. Additionally, a convolutional neural network (CNN) was utilised to extract deep features from the spectral domain and combine them with spatial domain features, thus reducing dimensionality. The resulting fused spatial–spectral features were classified using a support vector machine. The joint denoising and feature fusion in this study’s spectral–spatial domain resulted in a notable improvement of 34.9 % in overall accuracy, achieving a score of 98.3 %. This approach exhibited superior performance, particularly in evaluating severely aged samples. The proposed approach enhances the accuracy in assessing the ageing status of composite insulators and enables pixel-level visualisation of ageing distribution. This assists in guiding the design of insulators’ shapes and materials for various environmental conditions. Moreover, this method is potentially applicable in detecting ageing in other electrical equipment.

An online state-of-health estimation method for lithium-ion battery based on linear parameter-varying modeling framework

The accurate estimation of state-of-health (SOH) is crucial for ensuring the safe and reliable operation of lithium-ion battery systems. However, the intimate coupling between SOH and state-of-charge (SOC) is often overlooked in existing estimation methods, leading to inaccurate estimates. To address this, we propose a linear parameter-varying (LPV) battery model that captures both gradual capacity degradation and rapid dynamic changes. This model integrates traditional linear models with emerging nonlinear models, providing a comprehensive online SOH estimation framework that effectively separates the effects of SOC in the LPV model structure. The model parameters are identified using a subspace algorithm with accelerated aging data. The proposed method is validated by accelerated aging experiments on two sets of battery samples, one for model development and another for model validation. The experimental data show that the LPV battery model can achieve high SOH estimation accuracy, with an average error of 2.85 % and 5.51 % for SOH, and 0.63 % and 1.20 % for capacity, respectively. The method also shows the advantages of being easy to implement and highly generalizable, making it suitable for different battery types and application scenarios.

Modeling study on the mechanical performance of CFRP/Al single-lap rivet joints under hygrothermal environmental conditions

Carbon Fiber Reinforced Polymers (CFRP) and aluminum alloys, owing to their exceptional mechanical properties and lightweight attributes, are extensively used in aircraft manufacturing. However, prolonged exposure to a hygrothermal environment can compromise the mechanical integrity of composite joint structures. In this paper, accelerated aging experiments were designed to test the mechanical properties of CFRP after hygrothermal aging, a novel mechanical property prediction model tailored for the hygrothermal coupled environment is presented. The model accurately predicts the modulus and strength of CFRP after hydrothermal aging. A three-dimensional finite element model for the CFRP interference riveted structure, considering a tri-coupled state of moisture, temperature, and force was established by the application of subroutine and field superposition. The precision of this finite element model has been affirmed through accelerated aging tests. By integrating finite element analysis with experimental methods, this research delves into the failure modes and mechanisms of CFRP and its joints under hygrothermal conditions. It was discerned that the hygrothermal environment undermines the bond between fibers and the matrix, resulting in pronounced interlaminar delamination and shear failure in CFRP. The failure forms gradually change from “flaky” at lower levels of aging to “filamentary” at higher levels of aging. For CFRP riveted structures, the hygrothermal conditions influence their loadbearing capability and shift the primary positions of failure.

Unveiling the Impact of Light-Induced Acceptor-Generated ROS on Device Stability in Organic Photovoltaics.

The intrinsic stability of the acceptor is a crucial component of the photovoltaic device stability. In this study, we investigated the efficiency and stability of the nonfused-ring acceptors LC8 and BC8 under indoor light conditions. Interestingly, we found that devices based on BC8 with terminal side chains exhibited a higher indoor efficiency and stability. Through accelerated aging experiments, we discovered that the acceptors generate singlet oxygen under light exposure with BC8 demonstrating lower levels of ROS compared to LC8. We attribute this difference to the modulation of the acceptor aggregation orientation. Furthermore, the generated reactive oxygen species (ROS) further deteriorate the acceptor structure, and this phenomenon is also observed in high-efficiency acceptor structures, such as Y6. Our research reveals important mechanisms of acceptor photo-oxidation processes, providing a theoretical basis for enhancing the intrinsic stability of acceptors.

Influence of electric field on moisture-absorbing characteristics at the FRP/RPUF interface: experimental study and molecular dynamics simulation

The interface between fiber-reinforced polymer (FRP) and rigid polyurethane foam (RPUF) is a crucial component of composite cross-arm, not only operating within high electric field environments but also vulnerable to water-induced deterioration. In this paper, the moisture-absorbing characteristics and aging mechanism at the FRP/RPUF interface under the influence of an electric field were investigated through accelerated aging experiments, molecular dynamics (MD) simulations, reactive force filed (ReaxFF) simulations and Density Functional Theory (DFT) analysis. The results indicated that the moisture-absorbing characteristics of the FRP/RPUF system could be divided into two stages: Stage I, dominated by free diffusion, and Stage II, dominated by physical absorption. In Stage I, the electric field inhibited the diffusion behavior of water molecules by affecting the mean square displacement (MSD) of water molecules and the free volume of the FRP/RPUF system. During Stage II, the intrusion of water deepened the aging degree of the system, resulting in the emergence of a large number of free volumes and noticeable channels for water transport at the interface. The electric field enhanced the chemical reaction activity of epoxy resin and polyurethane by influencing their frontier molecular orbital energy, thereby promoting the occurrence of hydrolysis reactions. This intensified the physical moisture absorption process, ultimately promoting the Stage II process.

Lifespan prediction procedure of volume nanogratings imprinted by femtosecond laser in optical glasses

Volume nanogratings imprinted by infrared femtosecond laser in oxide glasses exhibit a characteristic birefringent signature, which translates into measurable retardance. Upon thermal annealing, such signature is progressively erased, typical of nanograting erasure. In this work, we propose a procedure to predict the lifespan of nanogratings by two main approaches: 1/ numerical modeling of optical retardance ageing using the Rayleigh-Plesset equation, and 2/exploiting VAREPA (VAriable REaction PAthways) framework fed by simulated ageing data. By considering experimental time – temperature annealing conditions, the modeled retardance is gathered as a function of demarcation energy to build a so-called Master Curve and then compared to accelerated ageing experiments. The erasure constant rate k0 can be determined for 8 commercial optical glasses. Based on a distributed Rayleigh-Plesset model, k0 and activation energy distribution are linked to glass viscosity and its temperature dependency. Finally, we discussed the restrictions on VAREPA application for an accurate lifetime prediction. This work provides guidelines for the future development of nanogratings based devices and applications, including optical data storage, birefringent devices, and optical sensors, through a judicious choice of glass composition and associated properties.

Preparation of carbon dots using aminoquinoline as nitrogen source as full ultraviolet bands absorber and application of LED UV leakage protection

LED has the advantages of small size, low power consumption, instant lighting, etc., but there is a risk of ultraviolet leakage. Long-term exposure to ultraviolet rays can lead to skin pigmentation, photoaging and additional hazards. Carbon dots (CDs) are excellent material for UV-light absorber because of their multi-functional groups and extreme stability. In this paper, A-CDs which have wide absorption range from 200 to 500 nm were prepared by one-pot hydrothermal carbonization. Then, 3&4A-CDs is prepared in two ways, CDs mixing and raw material mixing, which with average and efficient absorption efficiency both in UVA bands and UVB bands. After 180 h of accelerated aging and switched the pH value, ultraviolet absorption intensity of 3&4A-CDs still remained above 97% and 99%, and the emission wavelength did not alter. Finally, 3&4A-CDs@CMC films were synthesized and the 0.45 wt% 3&4A-CDs@CMC film could reach 100% absorption in the full UV bond. After 180 h of accelerated aging experiments, ultraviolet absorption intensity of 3&4A-CDs@CMC film still remained above 95%. Due to the extremely excellent ultraviolet absorption efficiency of the 3&4A-CDs, the 0.45 wt% 3&4A-CDs@CMC film can effectively avoid the leakage of ultraviolet light without affecting the visible light emitting effect of LED. At present, the synthetic process of 3&4A-CDs is simple, low cost and environmentally friendly.

Carbon Quantum Dots for Long-Term Protection against UV Degradation and Acidification in Paper-Based Relics.

Paper-based cultural relics constitute a significant and invaluable part of human civilization and cultural heritage. However, they are highly vulnerable to environmental factors such as ultraviolet (UV) photodegradation and acidification degradation, posing substantial threats to their long-term preservation. Carbon quantum dots (CQDs), known for their outstanding optical properties, high water solubility, and good safety, offer a promising solution for slowing down UV damage and acidification of paper-based relics during storage and transportation. Herein, we propose a feasible strategy for the simple preparation of CQDs with high dispersion stability, excellent UV absorption, room-temperature phosphorescence, and photostability for the safety protection of paper. Accelerated aging experiments were conducted using UV and dry-heat aging methods on both CQD-protected paper and unprotected paper, respectively, to evaluate the effectiveness of CQD protection. The results demonstrate a slowdown in both the oxidation and acid degradation processes of the protected paper under both UV-aging and dry-heat aging conditions. Notably, CQDs with complex luminescence patterns of both fluorescence and room-temperature phosphorescence also endue them as enhanced optical anticounterfeiting materials for multifunctional paper protection. This research provides a new direction for the protection of paper-based relics with emerging carbon nanomaterials.

Change of soil bacterial communities in chemically stabilized chromium contaminated soils in an accelerated aging experiment

Chemical stabilization is a common strategy to clean Cr(VI) contaminated soils. Although many studies have reported both short-term and long-term performance of chemical stabilization, there is no work addressing the impacts of long-term Cr stability on soil bacterial communities after stabilization. In this study, an accelerated aging system that synchronized simulation acid rain leaching and freeze-thaw cycles was established for the first time. We investigated the change of Cr content, environmental variables and bacterial community structure after chemical stabilization by 50-year acid rain leaching and freeze-thaw cycle simulation. Chemical stabilization effectively decreased the content of soil Cr(VI), total Cr in leachate and Cr(VI) in leachate. Different aging conditions altered soil Cr(VI), total Cr in leachate and Cr(VI) in leachate to different extents, hinting at distinct mechanisms of long-term Cr instability between acid rain leaching and freeze-thaw cycle. Cr(VI) and chemical stabilization were identified as the most influential factors affecting soil bacterial community structure, and acid rain leaching and freeze-thaw cycle exhibited considerable but distinct impacts. Our findings provided deeper insights into the long-term restoration of bacterial community in chemically stabilized Cr(VI) contaminated soil and the long-term risk assessment of contaminated soil remediation.

Study on the Aging Mechanism of Textile Relics in Museum Collection Environment by Accelerated Aging Experiment

ABSTRACT The protection of textile relics against environment-induced aging is vital when planning exhibitions or storing in the museum. To effectively avoid the deterioration of textile relics caused by improper preservation environment, this study accordingly examines different museum-collection environment (temperature, humidity, light sources, and their combination) in terms of the damage potential they hold for textile relics. Results showed the temperature, humidity, and light source of the museum-collection environment induced the performance of textile relics to varying degrees, among which the influence of temperature and light source was significantly greater than that of humidity, and appropriate humidity was also conducive to easing the performance aging of textile relics induced by the storage environment. In addition, it was found that regardless of the museum collection environment, the performance aging of protein textile relics was significantly greater than that of cellulose textile relics, indicating that the decline in the performance of textile relics was related not only to the museum-collection environment, but also to the fiber molecular composition of textile relics. Therefore, in the subsequent storage process of textile relics, the characteristics of textile relics should be fully considered and classified storage to minimize damage induced by the museum-collection environment.

(Invited) Challenges for Accelerating Life Testing of Commercial Lithium-Ion Batteries

Life testing of commercial lithium-ion batteries is critical for predicting lifetime, anticipating failure, and guaranteeing safe operation of real-world battery energy storage systems. The traditional method for conducting life testing is to use accelerated aging experiments, where stress factors such as temperature, charge/discharge rate, or daily charge-throughput are pushed to extremes to drive cell failure, while taking care not to induce degradation mechanisms that do not reflect real-world use. But even ‘accelerated’ aging tests generally require 6 months to several years of testing to reach end-of-life for the current generation of mass-produced lithium-ion batteries. So, many efforts have been made to accelerate ‘accelerated aging’ of commercial cells throughout the battery community. But it is critical to ensure that the results of invasive or novel accelerated life testing experiments match well with not only changes to the electrochemical performance of traditionally aged cells, but also that the impacts of physical or chemical degradation mechanisms are also well characterized.This work compares the results of a 2-year accelerated aging test conducted on 23 commercial large-format NMC-Gr cells with a variety of other accelerated life testing experiments. Coin-cell experiments using both full-cell and symmetric-cell configurations were used to study the microstructural changes and electrochemical behavior of both NMC and graphite electrodes, with the small format allowing for destructive characterization of many test replicates throughout cell lifetime; these experiments can be conducted more quickly than their large-format counterparts, and enable more detailed understanding of the degradation trajectory than the large-format test. However, difficulties in transferring electrochemical trends from the coin-cell format to the large-format cell will be discussed. In addition, cascading failure mechanisms observed in the large-format cells may not occur in coin-cells due to differences in the mechanical and thermal environment of each system. Implications for the design of small-format accelerated life testing using electrodes harvested from commercial batteries will be discussed. Calendar aging was accelerated by monitoring daily self-discharge and quantifying both reversible and irreversible capacity losses; challenges for making quantitative predictions from short-term calendar aging tests will be presented.