Super Stability Research Articles

Dynamically Stabilizing Oxygen Atoms in Silver Catalyst for Highly Selective and Durable CO2 Reduction Reaction

AbstractOxide derived catalyst displays outstanding catalytic activity and selectivity in electrochemical carbon dioxide reduction reaction (CO2RR), in which, it is found that residue oxygen atoms play a pivotal role in regulating the catalyst's electronic structure and thus the CO2RR process. Unfortunately, the intrinsic thermodynamic instability of oxygen atoms in oxide derived catalyst under cathodic CO2RR potentials makes it unstable during continuous electrolysis, greatly hindering its practical industrial applications. In this work, we develop a pulsed‐bias technique that is able to dynamically stabilize the residue oxygen atoms in oxide derived catalyst during electrochemical CO2RR. As a result, the oxide derived catalyst under pulsed bias exhibits super catalytic stability in catalyzing electrochemical CO2RR, while keeping excellent catalytic activity and selectivity.

Achieving Higher Critical Current Density in LGPS-Based Lithium Metal Batteries via a Synergistic Interlayer for Physical Inhibition and Chemical Scavenging of Lithium Dendrites.

Li10.35Ge1.35P1.65S12 (LGPS) electrolyte has garnered attention due to its high ionic conductivity and processability. However, its strong incompatibility with lithium metal hinders its practical application. Conventional interlayer strategy isolates Li from LGPS, avoiding the detrimental side reactions, but lithium dendrite penetration is still a problem. To address the aforementioned challenges, we develop a PVDF-HFP-supported PDOL-based interlayer (PDOL/PVDF-HFP), which stabilizes the LGPS/Li interface by synergistically physically inhibiting and chemically scavenging lithium dendrites. The multifunctional feature of the interlayer comes from the use of a bifunctional initiator, InCl3. On the one hand, InCl3 induces the polymerization of DOL, forming a physical separator and protecting lithium from LGPS; on the other hand, in situ reactions between In3+/Cl- and Li form a LiCl/LiF/LiIn hybrid SEI, homogenizing the surface Li+ flux and suppressing lithium dendrite formation and penetration. In addition, an unexpected dynamic microdendrite scavenging is realized by virtue of the side reactions of LGPS/Li, which converts the undesirable reaction to be an advantage in our design. Benefiting from the comprehensive advantages of such design, the constructed sulfide-based solid-state batteries achieve a super low interfacial impedance of 5.1 Ω, a high critical current density (CCD) value over 5 mA/cm2, and a super long cycling stability over 8000 h. Our synergistic interlayer strategy would open an effective avenue for solving interfacial challenges for practical sulfide-based solid-state batteries.

Interstitial Oxygen Acts as Electronic Buffer Stabilizing High-Entropy Alloys for Trifunctional Electrocatalysis.

Understanding the effect of elements' oxygen affinity is essential for comprehending high-entropy alloys' (HEAs) complete properties. However, the origin of HEAs' oxygen-containing structure and stability remains poorly understood, primarily due to their diverse components, hindering synthesis and analysis. Herein, the O-doping HEAs (HEA-O) have demonstrated outstanding performance and stability in electrolyzed water and Zinc-air batteries which can be reassembled after being stable for more than 1600h when the zinc consumption is over. The experiment and DFT simulation demonstrate that Cr with strong oxygen affinity can introduce more oxygen into the system of HEAs. Consequently, interstitial oxygens act as electronic buffers making the binding energy of other metal elements move to a higher level. Additionally, O-doping lowers the d-band center promoting electrochemical activity and increasing vacancy formation energies of metal active sites leading to super stability. The study provides significant insights into the design and comprehension of interstitial oxygen-doped HEAs.

Regional Electron Delocalization Regulation Internalizes the Reduced‐Order‐Transformation of Polysulfides

AbstractThe step‐order or disproportionation conversion of lithium polysulfides (LiPSs) is still a blind box in LiS batteries (LSBs) system. The cation‐doped electrocatalyst (Fe‐CoS2@HCNF) is designed through modulating electron‐surrounding situation of the central atomic d‐band to promote regional electron‐directed LiPSs reduced‐order‐transformation (especially, Li2S4Li2S). Fe‐CoS2@HCNF satisfies the requirement of mass (electron/ion) transfer reaction, quantizing as multi‐osmosis‐connected transportation channels and an all‐encompassing interior space for sulfur reduction occurring. Based on experiments and DFT calculations, the introduced Fe presents a local electron deficiency state toward regulating regional electron delocalization between Fe and Co matrix, which induces the d‐band state of the metal site, strengthening the metal 3d orbital coupling interaction with S2−of LiPSs, further guiding the order‐transformation of intermediate LiPSs. Consequently, the Fe‐CoS2@HCNF electrode has excellent electrochemical properties, performing at 3.0 C with 0.064 % capacity decay per cycle, and even maintaining super cycle stability at a high sulfur loadings. In addition, the pouch cell assembled can also reach an initial specific capacity of 1070.3 mAh g−1 at 0.1 C, which can still show good long‐term cycle stability. This work provides a valuable prospect for analyzing SRR intermediate state by regional electron flow regulation of electrocatalyst in practical LSBs.

In Situ Generatable and Recyclable Oxygen Vacancy-Modified Fe2O3-Decorated WO3 Nanowires with Super Stability for ppb-Level H2S Sensing.

Detecting hydrogen sulfide (H2S) odor gas in the environment at parts-per-billion-level concentrations is crucial. However, a significant challenge is the rapid deactivation caused by SO42- deposition. To address this issue, we developed a sensing material comprising Fe2O3-decorated WO3 nanowires (FWO) with strong interfacial interaction. During the H2S sensing process, important oxygen vacancies (OVs) are generated in situ and are recyclable on the surface of the Fe2O3 cluster. This sensor achieves a response of 140 (Ra/Rg) toward 50 ppm of H2S at 250 °C, with an experimentally measured detection limit of 1 ppb. It also exhibits remarkable stability, with no significant change observed over a long period of 150 days. Based on a combination of in situ DRIFT and DFT calculations, we have identified that the overactivation of O2 is the key step in the formation of SO42-. This overactivation can be partially modulated by the synergistic effect of Fe2O3 decoration and the in situ generated OVs, regulating the oxidation product to SO2 rather than the toxic SO42-. Furthermore, the continuous generation of OVs compensates for the loss of active sites pertaining to SO42- deposition, thereby contributing to the excellent stability of the sensor. This study underscores the beneficial impact of in situ OV generation in FWO for H2S sensing, offering a dynamic strategy to enhance sensor performance, particularly in terms of stability.

Super stable tensegrities and the Colin de Verdière number ν $\nu $

AbstractA super stable tensegrity introduced by Connelly in 1982 is a globally rigid discrete structure made from stiff bars and struts connected by cables with tension. We introduce the super stability number of a multigraph as the maximum dimension that a multigraph can be realized as a super stable tensegrity, and show that it equals the Colin de Verdière number minus one. As a corollary we obtain a combinatorial characterization of multigraphs that can be realized as three‐dimensional super stable tensegrities. We also show that, for any fixed , there is an infinite family of 3‐regular graphs that can be realized as ‐dimensional injective super stable tensegrities.

Stability Conditions and Stiffness Variability of General Tensegrity Systems with Kinematic Joints

Abstract Tensegrity systems represent promising candidate mechanisms with in-situ stiffness variability through changing the cables' prestress levels. However, prestress-based stiffness behaviors of tensegrity systems with arbitrary kinematic joints have not been analyzed systematically. This paper adopts the natural absolute coordinates for static modeling of tensegrity systems consisting of rigid members and tension elements. Then, a generic stiffness analysis method is developed to formulate the reduced-basis tangent stiffness matrix, which is found to include three parts: positive semi-definite material and geometric stiffness matrices, and an indefinite constraint stiffness matrix. Based on these findings, a systematic stability-checking procedure is derived to determine prestress and super stability, which are qualitative indicators of the softening and stiffening effects in different tensegrity systems. Then, we proceed to quantify the range of prestress-based stiffness variability by formulating semidefinite programming problems that numerically pinpoint the maximum and zero stiffness points. Furthermore, this paper reveals the composable nature of multiple self-stress states, enabling the composability of stiffness properties in mechanism designs. Several numerical examples verify the efficacy and versatility of the proposed method and demonstrate interesting stiffness behaviors of tensegrity systems with kinematic joints.

Dynamically Stabilizing Oxygen Atoms in Silver Catalyst for Highly Selective and Durable CO2 Reduction Reaction.

Oxide derived catalyst displays outstanding catalytic activity and selectivity in electrochemical carbon dioxide reduction reaction (CO2RR), in which, it is found that residue oxygen atoms play a pivotal role in regulating the catalyst's electronic structure and thus the CO2RR process. Unfortunately, the intrinsic thermodynamic instability of oxygen atoms in oxide derived catalyst under cathodic CO2RR potentials makes it unstable during continuous electrolysis, greatly hindering its practical industrial applications. In this work, we develop a pulsed-bias technique that is able to dynamically stabilize the residue oxygen atoms in oxide derived catalyst during electrochemical CO2RR. As a result, the oxide derived catalyst under pulsed bias exhibits super catalytic stability in catalyzing electrochemical CO2RR, while keeping excellent catalytic activity and selectivity.

Lead-Free Perovskite With Efficient Tellurium Ion Activation for Multifunctional Applications.

Lead-free perovskite materials have received extensive attention due to their non-toxicity, super environmental stability and adjustable photoelectric properties. However, the inherent problems of low luminous efficiency and low photoluminescence quantum yields (PLQYs) limit its development in multifunctional applications. Here, Te4+ doped Cs2ZrCl6 with high luminous efficiency and stability for multifunctional applications are developed. Te4+ ions are used as emission centers to improve the optical properties of Cs2ZrCl6 to make efficient and stable single-component white light-emitting diodes (WLEDs), and can be used as scintillator materials to improve scintillation performance to achieve high-resolution and low-dose X-ray imaging detection. In addition, it is found for the first time that Te4+ ions can be introduced into the trap center, so that the Cs2ZrCl6:Te4+ perovskite material exhibits excellent persistent luminescence (PersL) and mechanoluminescence (ML) after X-ray radiation, which has potential applications in the fields of delayed imaging and stress sensing. This work provides a method for designing lead-free perovskites with high optical performance and scintillating properties, as well as developing multifunctional applications.

Functional carbon dots induced defect configuration entropy strengthening polyanion cathode for ultrafast-charging sodium ion batteries in a wide temperature

The development of fast-charging and wide-temperature sodium-ion batteries (SIBs) is of great significance to all-climate energy storage. However, the gigantic challenge lies in achieving super dynamic performance and stability of cathode materials. Herein, the defect configuration entropy (DCE) is conceptualized in Na3V2(PO4)3/carbon composite (NVP/C) cathode by manipulating heteroatoms and vacancies in the surface carbon layer. It is found that the bonding energy between the carbon layer and NVP interface increases with the DCE. Accompanying, the Na+ migration energy barrier is reduced and the electronic conductivity is enhanced, which are pivotal factors underpinning the low-temperature performance. Furthermore, the increase of DCE engenders the formation of a NaF-rich cathode-electrolyte interface, furnishing support for high-temperature stability. As a result, the DCE-strengthened NVP/carbon composite cathode exhibits a high capacity of ∼88 mAh g−1 at an ultrahigh rate of 200 C (13 s per charge process). Moreover, the superior electrochemical performance in the wide temperature range of −30–60 °C is achieved with 0.101 % capacity decay per cycle at −20 ℃, and 0.0047 % capacity decay per cycle at 60 ℃.

Synthesis of uniform sized ZnS quantum dots using hydrodynamic cavitation and their characterization

As representative non-toxic cadmium-free quantum dots (QDs), ZnS QDs with high quantum efficiency, super stability and excellent biocompatibility had attracted wide attention in the fields of photocatalysis, solar cells and biomedicine. In this study, hydrodynamic cavitation (HC) technology was applied to the preparation of ZnS QDs. By adjusting HC device parameters, water soluble ZnS QDs with small particle size, narrow particle size distribution range, high absorbance, high luminous efficiency and high quantum yield were prepared. The morphology, size distribution, element composition and optical properties of ZnS QDs were studied by various characterization methods. ZnS QDs with average particle size of 1.48 nm, fluorescence quantum yield of 34.07% and Stokes shift of 112 nm were obtained. In addition, the mechanism of preparation of ZnS QDs by using HC method was also studied. It is hoped that this HC technology can provide a new idea for large-scale preparation of ZnS QDs with excellent properties.

Boosting supercapacitive performance of pristine covalent organic frameworks via phenolic hydroxyl groups: A two‐in‐one strategy

Two-dimensional covalent organic frameworks (COFs) are ideal electrode materials for electrochemical energy storage devices due to their unique structures and properties, and the accessibility and utilization efficiency of the redox-active sites within COFs are critical determinants of their pseudocapacitive performance. Via introducing meticulously designed phenolic hydroxyl (Ar-OH) groups with hydrogen-bond forming ability onto the imine COF skeletons, DHBD-Sb-COF exhibited improved hydrophilicity and crystallinity than the parent BD-Sb-COF, the redox-active sites (SbPh3 moieties) in COF electrodes could thus be highly accessed by aqueous electrolyte with a high active-site utilization of 93%. DHBD-Sb-COF//AC provided an excellent supercapacitive performance with an energy density of 78 Wh Kg−1 at the power density of 2553 W Kg−1 and super cycling stability, exceeding most of the previously reported pristine COF electrode-based supercapacitors. The “two-in-one” strategy of introducing hydroxyl groups onto imine COF skeletons to enhance both hydrophilicity and crystallinity provides a new avenue to improve the electrochemical performance of COF-based electrodes for high-performance supercapacitors.

Stability analysis of power system under n-1 contingency condition

Several voltage stability indices (VSIs) have been developed to assess the potential for voltage collapse. However, certain indexes are computationally costly. Meanwhile, some have been noted to underperform across various conditions. This work proposes a novel line index called the super voltage stability index (SVSI) to calculate the system's voltage stability margin (VSM). The suggested approach is based on the transmission system's two bus systems. The reactive power loss and N-1 contingency conditions to voltage sensitivity is a unique calculation approach used in this study to identify voltage instability. Day to day, the demand for electric power is being increased due to incessant increments in technology and population growth. Therefore, the power system networks are under pressure. The operational conditions of transmission system networks are affected at this point, which may result in voltage collapse. Regular monitoring of power supply is essential to avert voltage collapse. The effectiveness of the suggested index has been assessed using the IEEE 5 and 30-bus systems across diverse operating scenarios, including variations in active and reactive power loading as well as single line losses. The findings indicate that SVSI provides a more reliable indication of the proximity to voltage collapse when compared to conventional line VSIs.

A semi-flexible polybenzimidazole with enhanced comprehensive performance for high-temperature proton exchange membrane fuel cells

Although phosphoric acid-doped PBI holds great promise for application in high-temperature proton exchange membrane fuel cells, the stabilities of phosphoric acid-doped membranes are compromised due to the low absorption capacity of phosphoric acid, poor solubility and difficulty in processing. In this study, by introducing poly (5-phenyl-1H-1,2,3-triazole) monomers into the polybenzimidazole main chains, a semi-flexible polybenzimidazole (PBI-QP) was prepared. The mechanical properties of PBI-QP membranes were better than that of PBI membrane. The tensile strength of PBI-QP-20 reached to 130.9 MPa. Compared with PBI, the solubility of PBI-QP has improved significantly. PBI-QP can be easily dissolved in the solvents of DMF, DMSO and formic acid separately at room temperature. All the membranes exhibited super thermal stability. At 800 °C there is still 72% quantity of residue and the thermal stability of PBI-QP can meet the thermal stability requirements of HT-PEMFCs. The membranes of PBI-QP demonstrated high phosphoric acid absorption (ADL 10.5) and enhanced antioxidant properties. The proton conductivity is 64.3 mS∙cm−1 at 170 °C and the peak power density attains an impressive level of 573.6 mW cm−2 at 180 °C. The results indicate that the synthesized HT-PEMs exhibit excellent solubility and impressive peak power density, underscoring their substantial promise for utilization in HT-PEMs.

Carbon-modified bentonite ion-exchange electrode in rocking-chair capacitive deionization with superior desalination capacity and high stability

Conventional carbon electrodes possess low desalination capacity and poor cycling stability, while faraday electrode materials are not economical with limited resource for capacitive deionization (CDI) technology. Therefore, exploring new type of electrode materials with high desalination capacity, low cost and excellent cycle stability is highly desirable. Bentonite (Bent) is an excellent ion-exchange material, with high natural abundance, super stability, but it has low conductivity. In this paper, a nitrogen-doped carbon modified Bent (NC@Bent) was prepared by in-situ polymerization of dopamine on the surface of Bent followed by carbonization. The N,C-modified thin layer on Bent improved the conductivity, boosting the charge transportation and ion diffusion. The NC@Bent was used as ion-adsorption electrode, exhibiting excellent electro-adsorption behavior. In a rocking-chair CDI (RCDI) cell, it delivered an extraordinary desalination capacity of 82 mg g−1 and super cycling stability with 90 % capacity retention in 50 cycles. Finally, the total dissolved salts in the actual groundwater were effectively reduced by using the current RCDI cell, meeting the WHO recommendation for drinking water. In consideration of the unique feature of low-cost and non-toxicity of Bent, this ion-exchange electrode material (NC@Bent) has much potential for drinking-water purification.

Enhanced coalbed methane well production prediction framework utilizing the CNN-BL-MHA approach

As the mechanization of the CBM extraction process advances and geological conditions continuously evolve, the production data from CBM wells is deviating increasingly from linearity, thereby presenting a significant challenge in accurately predicting future gas production from these wells. When it comes to predicting the production of CBM, a single deep-learning model can face several drawbacks such as overfitting, gradient explosion, and gradient disappearance. These issues can ultimately result in insufficient prediction accuracy, making it important to carefully consider the limitations of any given model. It’s impressive to see how advanced technology can enhance the prediction accuracy of CBM. In this paper, the use of a CNN model to extract features from CBM well data and combine it with Bi-LSTM and a Multi-Head Attention mechanism to construct a production prediction model for CBM wells—the CNN-BL-MHA model—is fascinating. It is even more exciting that predictions of gas production for experimental wells can be conducted using production data from Wells W1 and W2 as the model’s database. We compared and analyzed the prediction results obtained from the CNN-BL-MHA model we constructed with those from single models like ARIMA, LSTM, MLP, and GRU. The results show that the CNN-BL-MHA model proposed in the study has shown promising results in improving the accuracy of gas production prediction for CBM wells. It’s also impressive that this model demonstrated super stability, which is essential for reliable predictions. Compared to the single deep learning model used in this study, its prediction accuracy can be improved up to 35%, and the prediction results match the actual yield data with lower error.

Two-response surface design optimization of carboxylated CNCs with super high thermal stability and dye removal capability

Discharging wastewater from industrial dyeing and printing processes poses a significant environmental threat, necessitating green and efficient adsorbents. Cellulose nanocrystals (CNCs) have emerged as a promising option for dye adsorbing. However, the industrial production and commercialization of CNCs still faced low yield, time-consuming, and uneco-friendly. In this study, we proposed a facile hydrochloric/maleic acid (HCl/C4H4O4) hydrolysis method to synthesize carboxylated CNCs using Box-Behnken design and dual response surface design, which can systematically investigate the effect of experimental factors (temperature, time and HCl/C4H4O volume ratio) on the final products. The rod-liked carboxylated CNCs gave the highest yield of 90.50 %, maximum carboxyl content of 1.29 mmol/g, and efficient dye removal ratio of 91.5 %. Furthermore, compared to CNCs obtained by commonly sulfuric acid hydrolysis way (CNCs-S) with a Tmax of 242.6 °C, the CNCs extracted at 5 h exhibited significantly improved thermal stability with Tmax reaching 351.2 °C. The enriched carboxyl content and excellent thermal stability show potential wastewater treatment applications under harsh conditions.

Ultrastable Luminol-OH--(Ni-WOx-CNT) ECL System with High Strength and Its Applications in Sensing.

In traditional luminol electrochemiluminescence (ECL) systems, hydrogen peroxide (H2O2) and dissolved oxygen (DO) are the commonly used coreactants to generate reactive oxygen species (ROS) for ECL emission. However, the self-decomposition of hydrogen peroxide and the limited solubility and content of oxygen in solution undoubtedly restrict the luminescence efficiency and stability of the luminol ECL system. Inspired by the ROS-mediated ECL mechanism, we pioneered hydroxide ion as an advanced luminol ECL coreactant using nickel-doped and carbon nanotube-modified tungsten oxide (Ni-WOx-CNT) as the coreactant accelerator. Owing to the excellent catalytic activity of Ni-WOx-CNT, amounts of ROS were generated from OH- at a low excitation voltage, which subsequently reacted with luminol anion radicals and triggered intense ECL signals. Experiments confirmed an impressive ECL behavior in terms of high luminescent intensity (85,563 a.u.) and super stability over 1300 consecutive tests; both are superior to those recently reported luminol-H2O2 and luminol-DO systems with smaller ECL intensities and consecutive tests less than 25 times. To validate the feasibility and versatility of the developed system in sensor, traditional three-electrodes system and closed bipolar electrodes system with various sensing strategies of direct oxidation, "gate-effect" of molecularly imprinted polymer, immune reaction, and enzyme-catalyzed reaction were proposed to monitor uric acid (UA), C-reactive protein (CRP), immunoglobulin G (IgG), and glucose (Glu). The superior sensing performances confirmed the great application potential of the developed ROS-mediated ECL system.

Broadband NIR phosphor Gd3Lu2Ga3O12: Cr3+, Yb3+ with high thermal stability

Broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have become important as new NIR light sources in NIR spectroscopy and NIR imaging techniques. However, currently developed broadband NIR phosphors commonly suffer from weak emission and poor thermal stability. In this work, a series of Gd3Lu2Ga3O12: Cr3+ phosphors were synthesized via high-temperature solid-state reaction. Under 460 nm excitation, the phosphors exhibit an intense emission spanning from 650 to 1150 nm with a full width at half maximum (FWHM) of 122 nm. After introducing Yb3+ as a co-dopant, the emission of the phosphor has been broadened greatly. Interestingly, the studied phosphors demonstrate super high thermal stability in a wide temperature range of 35–560 K, with the integrated emission intensity fluctuating within 10 %. At 435 K, the emission intensity of Gd3Lu2Ga3O12: 0.03Cr3+ remains 99.5 % and Gd3Lu2Ga3O12: 0.03Cr3+, 0.01 Yb3+ keeps 102.7 % of the initial intensity at room temperature. These NIR phosphors have been encapsulated with a common commercial 460 nm blue LED chip to fabricate a pc-LED device. The NIR output power of the device reaches 23.93 mW@100 mA, with a photoelectric conversion efficiency of 9.81 % at 20 mA current. The applications of the prepared NIR light source in night vision, and bioimaging have been demonstrated. The results show that these Cr3+/Yb3+ doped garnet phosphors can be effectively used in NIR light sources.

Hierarchical nanocomposites of redox covalent organic frameworks nanowires anchored on graphene sheets for super stability supercapacitor

Covalent organic frameworks (COFs) have shown significant potential as ideal electrode materials for supercapacitors (SCs) due to their highly accessible surface areas and tunable active sites. However, their poor electrochemical properties hinder their application prospects in electrochemical energy storage devices. Herein, we successfully synthesized two-dimensional COF (TpPa-(OH)2) nanowires anchored on the surface of reduced graphene oxide (TpPa-(OH)2/rGO) using a facile hydrothermal method in aqueous solution. The anchored COFs nanowires effectively prevent graphene sheets from stacking, thereby enhancing the electronic double layer capacitor of rGO and introducing pseudo-capacitance contributed by the redox COFs. Additionally, rGO's inherent conductivity facilitates electron transfer and ion migration, improving electrochemical properties. By regulating the content ratio of graphene and COF, the optimal TpPa-(OH)2/rGO shows obvious COFs nanowires structure anchored on graphene sheets and exhibits exceptional electrochemical performance, with a high specific capacitance of 371.1 F/g at 0.5 A/g and excellent cycle stability of 93% after 20,000 cycles at 10 A/g. Furthermore, we assembled symmetric SCs (SSCs) using TpPa-(OH)2/rGO-3, achieving a specific capacitance of 197.1 F/g at 0.2 A/g and delivering a maximum energy density of 16.6 Wh/kg at a power density of 158.7 W/kg. These results unambiguously indicate the significant potential of TpPa-(OH)2/rGO as a high-performance electrode material in energy-storage devices.