Excellent Long-term Performance Research Articles

Heat-Resistant Carbon-Coated Potassium Magnesium Hexacyanoferrate Nanoplates for High-Performance Potassium-Ion Batteries.

Metal hexacyanoferrates (HCFs) are regarded as promising cathode materials for potassium-ion batteries (PIBs) on account of their low cost and high energy density. However, the difficult-to-remove [Fe(CN)6] vacancies and crystal water lead to structural instability and capacity deterioration as well as the stereotype of poor thermostability of conventional HCFs. Herein, we report (100) face-oriented potassium magnesium hexacyanoferrate (KMgHCF) nanoplates with low [Fe(CN)6] vacancies and high crystallinity, enabling thermostability up to 550 °C, high-temperature carbon coating and crystal water elimination. The as-obtained KMgHCF/C nanoplates exhibit superior potassium storage properties, including a large reversible capacity of 84.6 mAh g-1, a high voltage plateau of 3.87 V, excellent long-term cycling performance over 15000 cycles and high rate capability at 5 A g-1. The unprecedented cycling stability of KMgHCF/C is attributed to the synergistic effect of a highly reversible two-phase reaction, low [Fe(CN)6] vacancies and no crystal water, a specially exposed steady (100) surface, and a protective carbon coating. This work provides a new material selection and modification strategy for the practical application of HCFs in PIBs.

A plasma electrolytic oxidation coating on high-purity Mg with excellent long-term degradation performance and biocompatibility

A neutral electrolyte was used to prepare plasma electrolytic oxidation (PEO) coatings on biodegradable high-purity Mg (HP-Mg). Formation mechanism, surface morphology, and chemical compositions of the PEO coating were investigated. It was found that a porous layer formed first at the low cell voltage with an outward-growth characteristic, and then a dense layer was inward formed after the cell voltage reached the critical voltage. The main compositions of the PEO coating were MgF2, K2MgF4, KMgF3, Mg3(PO4)2, and MgO. Electrochemical measurements were carried out in simulated body fluid (SBF) at 37 °C to evaluate the long-term degradation performance. The coated HP-Mg exhibited superior degradation properties, and the coating remained intact over 180 days of degradation. During the degradation process, the pores and microcracks within the coating would gradually be filled with degradation products, enhancing the coating adhesion strength. The results of the cytotoxicity test validated the biosafety of the coating. Besides, a high-quality coating can be fabricated on the surface of biodegradable orthopedic Mg screws using this PEO treatment. The PEO coating possessed excellent degradation performance and biocompatibility, showing great potential in the practical production of biodegradable Mg implants.

Quasi-Gel Polymer Electrolyte Interfaced with Electrodes through Solvent-Swollen Poly(ethylene oxide) for High-Performance Lithium/Lithium-Ion Batteries.

Solid polymer electrolytes (SPEs) are regarded as a superior alternative to traditional liquid electrolytes of lithium-ion batteries (LIBs) due to their improved safety features. The practical implementation of SPEs faces challenges, such as low ionic conductivity at room temperature (RT) and inadequate interfacial contact, leading to high interfacial resistance across the electrode and electrolyte interfaces. In this study, we addressed these issues by designing a quasi-gel polymer electrolyte (QGPE), a blend of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide) (PEO), and succinonitrile (SN), with the desired mechanical strength, ionic conductivity, and interfacial stability through a simple solution casting technique. The QGPE features a thin solvated PEO layer on its surface, which wets the electrode, reducing the interfacial resistance and ensuring a homogeneous Li-ion flux across the interface. The optimized QGPE exhibits a good lithium-ion conductivity of 1.14 × 10-3 S cm-1 with a superior lithium-ion transference number of 0.7 at 25 °C. The Li/QGPE/Li symmetric cell exhibits a highly reversible lithium plating/stripping process for over 1300 h with minimal voltage polarization of ∼20 mV. The Li/QGPE/LiFePO4 full cell demonstrates good rate capability and excellent long-term cycling performance at a 0.1 C rate at 25 °C, maintaining a specific discharge capacity of 148 mAh g-1 over 200 cycles. The effectiveness of QGPE for LIBs is proven using a graphite/QGPE/LiFePO4 4 × 4 cm pouch cell, showcasing outstanding flexibility and tolerance against intentional abuse.

Rational Design of LixSiOy-Based Pre-SEI through Thermal-Evaporated Li-Metal Prelithiated SiOx Anode Enabling Extremely Stable and High-Rate Lithium Microbatteries

Recently, silicon oxides families (SiOx) have been commercialized as high capacity anode materials growing rapidly owing to their natural resource abundance and low-cost.(1) However, both the poor electron/ionic conductivity, and quite low initial coulombic efficiency (ICE) (normally < 60%) limits the further development into next generation SiOx anodes. (2) To address these two critical issues, various pre-lithiation strategies have emerged and systematically investigated with significant progress.(3, 4) Here, we provide a facile approach to prelithiate SiOx films by optimizing RF power and precisely controlling Li-metal deposition to overcome the current challenges of SiOx anodes. We found a strong correlation between the surface chemical state of SiOx and the pre-formation of LixSiOy SEI layers. The optimal prelithiation strategy achieves remarkable rate performance of 72.8% at 20C, and extremely excellent long-term cycling performance of 54.2% over 5000 cycles at 10C. This study significantly promotes SiOx-based anodes development, offering a promising strategy for extreme fast-charging and long-term stability not only overcoming the limitations in microbattery but scalable to practical electrodes.Reference: Q. Mai, Chem. Soc. Rev., 48, 285 (2019). M. L. Jiao, Y. F. Wang, C. L. Ye, C. Y. Wang, W. K. Zhang and C. Liang, J. Alloy. Compd., 842, 21 (2020). R. M. Zhan, X. C. Wang, Z. H. Chen, Z. W. Seh, L. Wang and Y. M. Sun, Adv. Energy Mater., 11, 20 (2021). X. Q. Min, G. J. Xu, B. Xie, P. Guan, M. L. Sun and G. L. Cui, Energy Storage Mater., 47, 297 (2022).

Tailoring physicochemical properties of quaternized polystyrene-ethylene/butylene-styrene membrane for enhanced pervaporation desalination

Pervaporation offers unique advantages for desalination of hypersaline water using highly hydrophilic and selective membrane. Positively charged membrane is superior in repelling cations and preventing scaling through electrostatic repulsion. This study investigates the quaternization and crosslinking of block copolymer styrene-ethylene-butylene-styrene (SEBS) membrane and explores the potential of quaternized membrane for pervaporation desalination. A one-step immersion process was proposed to easily adjust the physicochemical properties of membrane using trimethylamine (TMA) and N,N,N′,N′-tetramethyl-1,6-hexanediamine (TMHDA) for ammonium grafting and crosslinking. Compared to the quaternization with TMA or TMHDA alone, the combination of TMA and TMHDA produces a synergistic effect, improving crosslinking efficiency and facilitating the grafting reaction. This results in high ion exchange capacity (IEC) values and a transformation of microphase separation structure with more interconnected hydrophilic domains. An ultrahigh water permeability coefficient of 0.6 × 106–1.2 × 106 Barrer and highly intrinsic salt rejection were obtained in treating 3.5–20 wt% NaCl solution. The thin film composite QEBS/nylon membranes showed a superior water flux of 116.5 kg·m−2·h−1 and salt rejection of >99.99 % in desalinating 5 wt% NaCl solution at 85 °C. Additionally, the membrane exhibited excellent long-term performance stability and resistance to acid and alkali environment, showing great potential for desalination of hypersaline water.

Long-term outcomes after hypothermic oxygenated machine perfusion and transplantation of 1,202 donor livers in a real-world setting (HOPE-REAL study)

Despite strong evidence for improved preservation of donor livers by machine perfusion, longer post-transplant follow-up data are urgently needed in an unselected patient population. We aimed to assess long-term outcomes after transplantation of hypothermic oxygenated machine perfusion (HOPE)-treated donor livers based on real-world data (i.e., IDEAL-D stage 4). In this international, multicentre, observational cohort study, we collected data from adult recipients of HOPE-treated livers transplanted between January 2012 and December 2021. Analyses were stratified by donation after brain death (DBD) and donation after circulatory death (DCD), sub-divided by their respective risk categories. The primary outcome was death-censored graft survival. Secondary outcomes included the incidence of primary non-function (PNF) and ischaemic cholangiopathy (IC). We report on 1,202 liver transplantations (64% DBD) performed at 22 European centres. For DBD, a total number of 99 benchmark (8%), 176 standard (15%), and 493 extended-criteria (41%) cases were included. For DCD, 117 transplants were classified as low risk (10%), 186 as high risk (16%), and 131 as futile (11%), with significant risk profile variations among centres. Actuarial 1-, 3-, and 5-year death-censored graft survival rates for DBD and DCD livers were 95%, 92%, and 91%, vs. 92%, 87%, and 81%, respectively (log-rank p= 0.003). Within DBD and DCD strata, death-censored graft survival was similar among risk groups (log-rank p= 0.26, p= 0.99). Graft loss due to PNF or IC was 2.3% and 0.4% (DBD), and 5% and 4.1% (DCD). This study shows excellent 5-year survival after transplantation of HOPE-treated DBD and DCD livers with low rates of graft loss due to PNF or IC, irrespective of their individual risk profile. HOPE treatment has now reached IDEAL-D stage 4, which further supports its implementation in routine clinical practice. ClinicalTrials.gov Identifier: NCT05520320. This study demonstrates the excellent long-term performance of hypothermic oxygenated machine perfusion (HOPE) treatment of donation after circulatory and donation after brain death liver grafts irrespective of their individual risk profile in a real-world setting, outside the evaluation of randomised-controlled trials. While previous studies have established safety, feasibility, and efficacy against the current standard, according to the IDEAL-D evaluation framework, HOPE treatment has now reached the final IDEAL-D stage 4, which further supports its implementation in routine clinical practice.

One-step and universal fabrication of MXene/metal sodiophilic frameworks via Lewis acidic etching toward dendrite-free sodium metal anodes

Although MXene-based 3D scaffolds have boosted the cyclability of Na metal, the complex and harsh synthetic process deteriorates their practical application. Herein, a series of MXene/metal sodiophilic frameworks are constructed through one-step Lewis acidic etching, and metal nanoparticles are uniformly distributed on the surface or intercalated into the large interlayer gaps of MXenes. Notably, MXenes with superior Na+/electron transport kinetics and mechanical flexibility remarkably reduce the local current density, homogenize Na+ flux and cushion huge volume change of Na metal. Moreover, sodiophilic species including MXenes and metals effectively induce Na uniform nucleation and smooth deposition among the 3D matrixes, leading to dendrite-free morphology. Consequently, MXene/metal hosts exhibit stable Na plating/stripping process for 900 cycles with high average Coulombic efficiencies of 99.9% (2 mA cm−2, 1 mAh cm−2). The MXene/metal-Na symmetric cells achieve low overpotentials of less than 15 mV and stable cycling for 2200 h (2 mA cm−2, 4 mAh cm−2). When paired with Na3V2(PO4)3 cathode, the full cells with a low N/P ratio (around 2) demonstrate high discharge capacity and excellent long-term cyclic performance over 600 cycles. The presented universal, safe and one-step approach in fabricating MXene/metal scaffolds shows bright prospects and may promote the development of alkali metal-based batteries.

In-situ grown ZnO-nanorods of slippery liquid-injected porous surface coating on Mg alloy with hydrophobic, durable, and anti-corrosion properties

In this work, an in-situ self-grown nano-ZnO/epoxy-based slippery lubricant liquid-injected porous surface (SLIPS) coating with a unique bilayer structure is reported to achieve robustness, hydrophobicity, and anti-corrosion properties. Dense epoxy coated ZnO nanoparticles are used as the anti-corrosion barrier layer. Self-grown ZnO nanorods provide a robust micro- and nano-rough porous structure. The lubricant perfluoropolyether (PFPE) is strongly locked into the porous structure via low surface energy material pretreatment and capillary effect. This SLIPS coating has a high water contact angle (WCA) value and has excellent repellency to various liquids. The SLIPS surface maintains a high contact angle of more than 115° even after 20 days of immersion in corrosive solutions and withstand the erosion of corrosive solutions with pH = 3. It also has a very low corrosion current density of 8.97 × 10−12 A/cm2 and the Rct (the charge transfer resistance) of optimum SLIPS remained 1.41 × 108 ohm cm2 after 70 days immersion in 3.5 wt% NaCl solution, which is in the same order of magnitude as the initial value. The SLIPS coating with excellent mechanical stability, super-hydrophobicity, anti-fouling, chemical stability, and long-term corrosion resistance performance possesses tremendous application potential in long-term corrosion protection of Mg alloys.

Healable and Conductive Two-Dimensional Sulfur Iodide for High-Rate Sodium Batteries.

Self-healing functional materials can repair cracks and damage inside the battery, ensuring the stability of the battery material structure. This feature minimizes performance degradation during the charging and discharging processes, improving the efficiency and stability of the battery. Here, we have developed a novel healing conductive two-dimensional sulfur iodide (SI4) composite cathode. This process integrates both sulfur and iodine compounds into carbon nanocages, forming a SI4@C core-shell structure. This cathode design improves electrical conductivity and repairability, facilitates rapid activation, and ensures structural integrity, resulting in a typical Na-SI4 battery with high capacity and an exceptionally long cycle life. At 10.0 A g-1, the capacity of the Na-SI4 battery can still reach 217.4 mAh g-1 after more than 500 cycles, and the capacity decay rate per cycle is only 0.06%. In addition, the cathode exhibits a cascade redox reaction involving S and I, contributing to its high capacity. The in situ growth of a carbon shell further enhances the conductivity and structural robustness of the entire cathode. The flexibility and bendability of SI4@C-carbon cloth make it applicable for flexible electronic devices, providing more possibilities for battery design. The strategy of engineering a two-dimensional self-healing structure to construct a superior cathode is expected to be widely applied to other electrode materials. This study provides a new pathway for designing novel binary-conversion-type sodium-ion batteries with excellent long-term cycling performance.

Fouling-Free electrochemical strategy based on vertically-aligned peptide layer for cardiac troponin I sensitive detection in human serum

BackgroundCardiac troponin I (CTnI) is demonstrated as one of the most promising disease biomarkers for early diagnosing acute myocardial infarction (AMI). To date, electrochemical immunosensors have been extensively studied in the field of cTnI determination. But highly accurate and sensitive cTnI detection by this method is still a challenge due to non-specific adsorption on electrode interfaces in complex human serum. As a result, it is necessary to develop an antifouling electrochemical immunosensor with high sensitivity for the detection of cTnI. ResultsIn this work, an antifouling electrochemical immunosensor was constructed based on vertically-aligned peptide layer consisting of Au nanoparticles (AuNPs) and amphiphilic CEAK16 peptide (CEAK16@AuNPs) for sensitive and accurate detection of cTnI in human serum. The vertically-aligned CEAK16@AuNPs interface provided a stable hydration layer originated from attraction of water molecules by amino acids on the hydrophilic side of the CEAK16, which effectively reduced non-specific adsorption and enhanced electron transfer rate. The cTnI immunosensor possessed great analytical performance with a wide range from 1 fg mL−1 to 1 μg mL−1 and a low detection limit of 0.28 fg mL−1 (S/N = 3). Additionally, the proposed CEAK16@AuNPs sensing interface showed excellent long-term antifouling performance and electrochemical activity that preserved 80 % of the initial signal after 20-days exposure in human serum samples. Consequently, the cTnI immunosensor displayed excellent detection accuracy compared to clinical methods and owned good selectivity, stability and reproducibility. SignificanceThe development of this strategy provides a versatile tool for accurate quantitative cTnI analysis in real human serum, thus helping to achieve early AMI diagnosis effectively and holding the promising potentials for other immunosensor in disease diagnosis.

Experimental study on the dynamic behavior of a new medium–low-speed maglev subgrade structure

Constructing medium–low-speed magnetic levitation (MLS maglev) subgrade by borrowing the construction standards of high-speed railway (HSR) subgrade can result in enormous engineering waste because the amplitude, distribution width, and dynamic coefficient of the dynamic load of MLS maglev trains are much smaller than those of HSR trains. To address this problem, an innovative subgrade structure was proposed to match the dynamic loads of MLS maglev trains. Two experimental models are constructed to study the proposed MLS maglev subgrade at train speeds of 100 km/h, 120 km/h, 160 km/h, and 200 km/h. The two models are labeled as Models I and II, and the only difference between these two models is the type of surface layer material of the subgrade bed, whereas the other structural features are the same. Specifically, the Model Ⅰ employs graded gravel, whereas the Model Ⅱ uses A group filling. The experimental results indicate that for both models, the dynamic earth pressure amplitudes are all less than 20 % of the subgrade’s self-weight at the bottom surface of the subgrade bed. In addition, the cumulative settlement of the two models is below the cumulative settlement limit. Although both models with the proposed MLS maglev subgrade exhibit excellent long-term performance, the Model Ⅰ has superior attenuation characteristics of dynamic earth pressure, and smaller acceleration and dynamic deformation than that the Model Ⅰ. This is attributed to the graded gravel used in the Model Ⅰ, which possesses a greater dynamic modulus and damping ratio than the A group filling used in the Model Ⅱ. The results presented in this study could contribute to the comprehension of the dynamic behavior of the subgrade under the dynamic loads of MLS maglev trains. More importantly, compared to the existing MLS maglev subgrades, the proposed MLS maglev subgrade has lower construction standards and is thus suitable for practical engineering applications.

Polypyride intercalation boosting the kinetics and stability of V3O7·H2O cathodes for aqueous zinc-ion batteries

V3O7·H2O (VO) is a high capacity cathode material in the field of aqueous zinc ion batteries (AZIBs), but it is limited by slow ion migration and low electrical conductivity. In this paper, polypyridine (PPyd) intercalated VO with nanoribbon structure was prepared by a simple in-situ pre-intercalation, which is noted VO-PPyd. The total density of states (TDOS) shows that after the pre-intercalation of PPyd, an intermediate energy level appears between the valence band and conduction band, which provides a step that can effectively reduce the band gap and enhance the electron conductivity. Furthermore, the density functional theory (DFT) results found that Zn2+ is more easily de-intercalated from the V-O skeleton, which proves that the embeddedness of PPyd improves the diffusion kinetics of Zn2+. Electrochemical studies have shown that VO-PPyd cathode materials exhibit excellent rate performance (high specific capacity of 465 and 192 mA h g−1 at 0.2 and 10 A g−1, respectively) and long-term cycling performance (92.7% capacity retention rate after 5300 cycles), due to their advantages in structure and composition. More importantly, the energy density of VO-PPyd//Zn at 581 and 5806 W kg−1 is 375 and 247 W h kg−1, respectively. VO-PPyd exhibits excellent electrochemical properties compared to previously reported vanadium based cathodes, which makes it highly competitive in the field of high-performance cathode materials of AZIBs.

Bio-inspired gradient poly(lactic acid) nanofibers for active capturing of PM0.3 and real-time respiratory monitoring

The concept of bio-inspired gradient hierarchies, in which the well-defined MOF nanocrystals serve as active nanodielectrics to create electroactive shell at poly(lactic acid) (PLA) nanofibers, is introduced to promote the surface activity and electroactivity of PLA nanofibrous membranes (NFMs). The strategy enabled significant refinement of PLA nanofibers during coaxial electrospinning (∼40 % decline of fiber diameter), accompanied by remarkable increase of specific surface area (nearly 1.5 m2/g), porosity (approximately 85 %) and dielectric constants for the bio-inspired gradient PLA (BG-PLA) NFMs. It largely boosted initial electret properties and electrostatic adsorption capability of BG-PLA NFMs, as well as charge regeneration by TENG mechanisms even under high-humidity environment. The BG-PLA NFMs thus featured exceptionally high PM0.3 filtration efficiencies with well-controlled air resistance (94.3 %, 163.4 Pa, 85 L/min), in contrast to the relatively low efficiency of only 80.0 % for normal PLA. During the application evaluation of outdoor air purification, excellent long-term filtering performance was demonstrated for the BG-PLA for up to 4 h (nearly 98.0 %, 53 Pa), whereas normal PLA exhibited a gradually declined filtration efficiency and an increased pressure drop. Moreover, the BG-PLA NFMs of increased electroactivity were ready to generate tribo-output currents as driven by respiratory vibrations, which enabled real-time monitoring of electrophysiological signals. This bio-inspired gradient strategy opens up promising pathways to engender biodegradable nanofibers of high surface activity and electroactivity, which has significant implications for intelligent protective membranes.

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.

Long-term Outcomes With Expanded Polytetrafluoroethylene Valved Conduits in Pediatric Patients

BackgroundThe expanded polytetrafluoroethylene (ePTFE) valved conduit (VC) has been reported for pulmonary valve replacement (PVR). The purpose of this study was to review long-term outcomes of our trileaflet ePTFE VC. MethodsThis multicenter study was performed with institutional review board approval from each institution. Our VC is fashioned from commercially available ePTFE tube grafts (for the conduit) and 0.1-mm-thick ePTFE membrane (for the trileaflet material). The patients were followed up in our clinic. Valve function was assessed by echocardiography in the operating room and at follow-up clinic visits after implantation. ResultsFifty-five patients received ePTFE VC between 2012 and 2023 (16-28 mm in diameter). Patients’ age at the time of implantation ranged from 6 months to 20 years (median, 7.5 years). Clinical follow-up ranged from 4 days to 10.1 years (average, 3.6 years). There were no hospital deaths. There were 2 non–valve-related late deaths. There have been no cases of endocarditis. Two patients required balloon dilation for the distal pulmonary artery stenosis, and 1 patient required residual ventricular septal defect closure. Five patients have received transcatheter PVR (TPVR) because of increased pressure gradient across the VC. Freedom from TPVR at 10 years was 90%. No valves required explantation or surgical replacement. ConclusionsCompared with historical data for other PVR options, our ePTFE VC shows excellent long-term performance and, when required, provides an easily accessible “landing zone” for TPVR. Our technique is easily learned, is reproducible, and can be a valuable option for surgeons performing PVR in pediatric patients.

Durable bionic honeycomb slippery liquid-infused porous surfaces with anti-icing and water-collecting properties

The slippery liquid-infused porous surfaces with nanostructures have emerged as a high-performance multifunctional surface with super-liquid repellency, low contact angle hysteresis and self-healing. However, the amount of lubricant captured by the nanostructures is extremely low, and such oil-filled functional surfaces are susceptible to lubricant loss depletion. In this research, we developed a honeycomb-inspired multidimensional lubricant-infused surface that has a good ability to lock in lubricant while providing excellent mechanical durability. The honeycomb-shaped hexagonal micropores store lubricant to stabilize the smooth oil layer, while the pine-needle shaped nano-needles in the pores retain the lubricant in the pores, making it more difficult to lose the lubricant and increasing durability. Compared to conventional nanostructured slippery liquid-infused porous surfaces, this surface ensures excellent long-term lubrication performance under extreme conditions such as cooling, high shear and water spray impact. Meanwhile the honeycomb mesh lubricant injected into the surface is able to rapidly coalesce and remove water droplets during condensation due to the presence of coarsening effect, and it also retards the formation of ice. This structure provides a new idea for anti-icing and water collection research

In situ polymerization design of a quasi-solid electrolyte enhanced by NMP additive for lithium metal batteries

Solid polymer electrolytes (SPEs) are considered one promising candidate for lithium metal batteries due to their high flexibility, low cost, and roll-to-roll scalability. However, conventional SPEs prepared via ex situ methods are confronted with challenges such as poor contact and high resistance at the electrode|SPE interface, as well as low ionic conductivity at room temperature. In this study, we developed a quasi-solid electrolyte (QSE) using an in situ polymerization approach, employing butyl acrylate as the monomer and incorporating NMP as an additive. Spectroscopic investigations and DFT calculations revealed that NMP tends to form an overleaf-structured [Li(NMP)3][TFSI] complex with LiTFSI, promoting lithium salt dissociation. Owing to this advantage, the QSE exhibits high room-temperature ionic conductivity (6.94 × 10−4 S cm−1) and an extensive electrochemical stability window (5.01 V vs. Li+/Li). Furthermore, the in situ polymerization method facilitates full contact at the interface, enhancing the interfacial stability and reducing the interface resistance, thus resulting in stable cycling of Li|Built-in QSE|Li symmetric cell for 1100 h at 0.1 mA cm−2. The assembled LiFePO4|Built-in QSE|Li cell also demonstrates excellent rate and long-term cycling performance. Our findings offer valuable insights into the interaction between organic additives and lithium salts and present a novel strategy for the development of polymer electrolytes.

Finite element model analysis of long-term performance of composite anchorage based on double-material parameters

Carbon fibre-reinforced polymer (CFRP) tendons demonstrate the advantages of light weight, high strength, and superior corrosion resistance and have broad application prospects for long-span cable structures. However, given the low transverse shear strength of CFRP tendons, how to achieve long-term and reliable anchorage for CFRP tendons is a critical issue. The long-term performance (LTP) of a novel composite anchorage for CFRP tendon was assessed in this study. Then, a finite element model (FEM) with double-material creep parameters was established to reliably model the LTP experiment according to the creep parameters of the bonding medium and CFRP tendon. Finally, the effects of the free section tendon length, pre-tightening force, over-tensioning force, and elastic modulus of the bonding medium were analysed using the established FEM with double-material creep parameters. Results revealed no visible damage to the CFRP tendon and anchorage after the LTP experiment. The maximum tendon slippage was 0.054 mm, and the residual load ratio was 0.826. These phenomena indicate that the novel composite anchorage has excellent LTP. The FEM modelling results based on double-material creep parameters were in good agreement with the experiment results. The residual load ratio calculated by the FEM was 1% lower than the experimental value. Through the parameter analysis, the residual load ratio of the specimen was effectively improved under longer free section tendon condition, but tendon slippage increased to a certain extent. In addition, the LTP of the composite anchorage can be effectively improved by appropriately decreasing pre-tightening force and over-tensioning force. When the over-tensioning force was 1.4 times the test load, the tendon slippage was reduced by 34.2%, and the residual load ratio increased by 4.8%. The greater elastic modulus of the bonding medium in the range of 2.1 GPa–3.1 GPa, the worse the LTP of the composite anchorage.

Design of Abrasion-Resistant, Long-Lasting Antifog Coatings.

Fog formation is a common challenge for numerous applications, such as food packaging, mirrors, building windows, and freezer/refrigerator doors. Most notably, fog forms on the inner surfaces of prescription glasses and safety eyewear (particularly when used with a mask), face shields, and helmet lenses. Fogging is caused by the distortion of light from condensed water droplets present on a surface and can typically be prevented if the surface static water contact angle (θ) is less than ∼40°. Such a low contact angle can be readily achieved by either increasing the substrate surface energy or by engineering surface nanotexture. Unfortunately, such nanotexture can be readily damaged with use, while high surface energy substrates get covered with low surface energy foulants over time. Consequently, even with numerous ephemeral antifog coatings, currently there are no commercially available, durable, and permanent antifog coatings. Here we discuss the development of a new class of high-performance antifog coatings that are abrasion-resistant and long-lasting. These polyvinylpyrrolidone-based coatings, designed based on the classical Ratner-Lancaster wear model, dramatically outperform the base polymer, as well as all tested commercially available antifog coatings. Specifically, these coatings exhibit a > 400% increase in fogging time compared to base polymer, a > 50,000% increase in wear resistance, and excellent long-term antifog performance. The developed coatings also significantly outperformed all tested commercially available antifog coatings in terms of their antifog performance, wear resistance, and long-term cyclical performance. Additionally, the key design strategies employed here─incorporation of toughening agents and hydrophilic slip additives─offer a new approach to developing high-performance, durable antifog coatings based on other well-known antifog polymers.

In-situ polymerisation of fluorene to achieve theoretical capacity in LiFePO4 cells

This study aims to enhance the electrochemical properties of solid-state lithium-ion batteries by modifying the cathode material, LiFePO4 (LFP), via fluorene addition and in-situ polymerisation. The first modification process involves creating a shell structure (the film thickness of 10 nm) around each LFP particle and establishing a net-like structure to connect the particles before the in-situ polymerisation. Then, electrochemical in-situ polymerisation during battery cycling with a low current and obtaining the composite cathode of lithium iron phosphate (LFP) and polyfluorene. The results demonstrate that adding 20 wt.% fluorene significantly reduces the transfer resistance and enhances the rate performance with the capacity retention of 95.2 % (from 0.1C to 2C and return to 0.2C) of the solid-state batteries. Additionally, the modified LFP cathode demonstrates excellent long-term cycling performance and exhibits capacity (167.2 mAh/g in 0.2 C) close to the theoretical limit, and Coulombic efficiency remains at 99.2 %.