Absorption Energy Research Articles

Environmental Effects on the Norbornadiene-quadricyclane Photoswitch for Molecular Solar Thermal Energy Storage

Today’s need for renewable energy combined with modern societies' reliability on on-demand power leads us to find solutions that can store excess or produce directly to storage for later use. A MOlecular Solar Thermal (MOST) based on norbornadiene/quadricyclane(NBD/QC) does the latter with an isomeric photoswitching molecule pair. The theoretical studies of molecular solar thermals (MOST) provide a needed understanding of potential synthetic candidates. We have investigated an array of more complex solvation models for the norbornadiene/quadricycle (NBD/QC) photoswitch and the impacts of the models on the first absorption energy. Our results have been obtained with various density functional theoretical methods and basis sets.

Synthesis and Self‐Assembly of Diborate Ester Polymers for Dielectric Elastomer Actuators

Inorganic nanoparticles have been widely used as fillers to modify dielectric elastomers to simultaneously improve mechanical and dielectric performances. Elegant interface design is crucial for achieving synergy between fillers and elastomers. Herein, we show that diborate ester polymers can both improve the interfacial compatibility between inorganic nanoparticles and elastomers and enhance the dielectric performances. The diborate ester polymers are derived from the condensation reaction between tetrakis(dimethylamino)diborane (or tetrahydroxydiborane) and a three‐armed catechol monomer. Choosing TiO2 nanoparticles as the inner core, a series of TiO2@diborate ester polymer core‐shell nanoparticles are synthesized. Density functional theory (DFT) calculations indicate that the diborate ester polymer shell tightly bonds to the surface of TiO2 through two dissociative bidentate bridging modes of the catechol monomer (absorption energy: −11.049 eV). These core‐shell nanoparticles can soften and tough polydimethylsiloxane (PDMS) and show enhanced interfacial binding affinity to PDMS than naked TiO2 nanoparticles. The fabricated composites have high dielectric constants (up to 6.8) and low dielectric losses (<0.03). The actuated strain and puncture voltage of the composites reach 25.9% and 80 V μm−1, respectively, which are much higher than those of PDMS and TiO2/PDMS. This work provides a promising route to fabricate core‐shell nanoparticles for high‐performance dielectric elastomers.

Ultra-Sleek High Entropy Alloy Tights: Realizing Superior Cyclability for Anode-Free Battery.

The development of Li-free anodes to inhibit Li dendrite formation and provide high energy density Li batteries is highly applauded. However, the lithiophobic interphase and heterogeneous Li deposition hindered the practical application. In this work, a 20nm ultra-sleek high entropy alloy (HEA, NiCdCuInZn) tights loaded with HEA nanoparticles are developed by a thermodynamically driven phase transition method on the carbon fiber (HEA/C). Multiple Li+ transport paths and abundant active sites are enabled by the cocktail effect of different constituent elements in HEA. These active sites with gradient absorption energies (-3.18 to -2.03eV) facilitate selective binding, providing a low barrier for homogeneous Li nucleation. Simultaneously, multiple transport paths promote Li diffusion behavior with uniform Li deposition. Thus, theHEA/C achieves high reversibility of Li plating/stripping processes over 2000 cycles with a coulombic efficiency of 99.6% at 5mA cm-2 /1 mAh cm-2 in asymmetric cells, as well as over 7200h at 60mA cm-2 /60 mAh cm-2 in symmetric cells. Moreover, the anode-free full cell with the HEA/C host has an average coulombic efficiency of 99.5% at 1 C after 160 cycles. This advanced HEA structure design shows a favorable potential application for anode-free Li metal batteries.

Biaxially Conjugated Materials for Organic Solar Cells.

Organic solar cells (OSCs) represent one of the most important emerging photovoltaic technologies that can implement solar energy conversion efficiently. The chemical structure of organic semiconductors deployed in the active layer of OSCs plays a critical role in the photovoltaic performance and chemical/physical stability of relevant devices. With the structure innovation of organic semiconductors, especially nonfullerene acceptors (NFAs), the performance of OSCs have been promoted rapidly in recent years, with state-of-the-art power conversion efficiencies (PCEs) exceeding 19.5%. Compared with other photovoltaics like perovskite, the shortcoming of OSCs mainly lies in the high nonradiative recombination loss. However, the photocurrent density is superior in OSCs owing to the easy modulation of the NFA band gap toward the near-infrared region. In these regards, the effort to further boost the PCE of OSCs to achieve a milestone >21% should be devoted to reducing the nonradiative loss while further broadening the absorption band. Developing organic semiconductors with biaxially extended conjugated structures has provided a potential solution to achieve these goals. Herein, we summarize the design rules and performance progress of biaxially extended conjugated materials for OSCs. The descriptions are divided into two major categories, i.e., polymers and NFAs. For p-type polymers, we focus on the biaxial conjugation on some representative building blocks, e.g., polythiophene, triphenylamine, and quinoxaline. Whereas for n-type polymers, some structures with large conjugated planes in the normal direction are presented. We also elaborate on the biaxial conjugation strategies in NFAs with modification site at either the π-core or side-group. The general structure-property relationships are further retrieved within these materials, with focus on the short-wavelength absorption and nonradiative energy loss. Finally, we provide an outlook for the further structure modification strategies of biaxially conjugated materials toward highly efficient, stable, and industry-compatible OSCs.

Gamma rays and neutrons attenuation performance of a developed lead borate glass for radiotherapy room.

The development of radiation therapy necessitated a continuous R&D for radiotherapy rooms' glass windows to reach the highest levels of protection for the staff of the radiotherapy facility. Therefore, in this article, a novel type of lead borate glass depending on parallel augmenting of lead and boron was produced to be used as gamma-rays and fast and thermal neutrons barriers in radiotherapy rooms. Neutrons and gamma rays' attenuation parameters, fast neutrons removal cross section ${\varSigma}_R$, thermal neutron total cross section ${\sigma}_T$, mass attenuation coefficient $\sigma$, linear attenuation coefficient μ, half-value layer, mean free path, effective atomic number Zeff, effective electron density Neff, and buildup factor for energy absorption (energy absorption buildup factor) and exposure (exposure buildup factor) were studied extensively. Three tools, Phy-X/PSD, EpiXS and XCOM computer programs and the standard mixture rules were utilized to estimate the attenuation parameters. The improvement caused by the augmentation of lead and boron in both gamma rays and neutrons attenuation was evident from the obtained results. The glass containing the highest lead and boron concentration PbB5, 40Pb-50B, which is the most efficient attenuator for gamma rays and both thermal and fast neutrons was recommended to be a distinguished choice as a shield in a radiotherapy room.

Defective band enhance the single green upconversion luminescence of Ca9Y(VO4)7: Yb3+/Er3+ phosphors by doping with Ba2+ ions

The present work investigates the near-single green emission properties of Ba2+ doped Ca9Y(VO4)7: Yb3+/Er3+ upconversion luminescence. The Ba2+ doped Ca9Y(VO4)7: Yb3+/Er3+ phosphors were successfully synthesized via the high-temperature solid-phase method. XRD pattern analysis showed that Ca9Y(VO4)7: Yb3+/Er3+/Ba2+ was a single phase, and Ba2+ doping did not induce heterophase phase. Under 980 nm near-infrared laser irradiation, Ca9Y(VO4)7: Yb3+/Er3+/Ba2+ phosphors emit strong green luminescence (530 nm, 2H11/2→4I15/2, 557 nm, 4S3/2→4I15/2) and weak red luminescence (664 nm, 4F9/2→4I15/2). The upconversion green-red luminescence integral intensity ratio of Ca9Y(VO4)7: Yb3+/Er3+/Ba2+ phosphor is 32.1. This enhancement can be attributed to the presence of defect bands that facilitate excitation photon absorption and efficient energy transfer from abundant electrons into Yb3+ (2F5/2) and Er3+ (4I11/2) ions. More importantly, the maximum SA and SR of Ca9Y(VO4)7: Yb3+/Er3+/Ba2+ phosphor as a temperature sensor are 1.44 % K−1 (at 548 K) and 1.28 % K−1 (at 298 K), respectively.

Excited-state proton transfer based fluorescence in Kaempferol powder and solutions with different concentrations

Kaempferol (KMP) is one of the most common flavonoids, currently being extensively studied for its numerous beneficial health effects. Here we study the fluorescence (FL) emission of KMP powder and of its solutions prepared using different types of solvents (polar and non-polar). In the spectra of KMP powder and KMP solutions with high concentration, the same FL peak with maximum at 1.9 eV is observed. Another FL peak, at higher energy of 2.45 eV, emerges in solutions, its relative intensity increases with decreasing solution concentration. The FL emission of solutions with lowest concentration displays only that peak. To calculate characteristic energies of absorption and emission of KMP molecule in vacuum and in solutions we use time-dependent density functional theory. Comparing the results of computations with measured FL spectra, we associate the FL band at 1.9 eV with the emission due to excited state intramolecular transfer of the proton of –OH5 hydroxyl group. The FL emission at 2.45 eV is related to the –OH3 proton transfer. We measure the FL spectra of KMP powder using two different excitation energies, 3.06 eV and 2.33 eV, and find that its FL spectrum depends on the excitation energy. To understand that dependence, we compare the FL spectra of KMP and Q monohydrate powders. We consider the excited state intermolecular transfer of the proton from –OH3′ hydroxyl group to a neighboring molecule in Q crystal and calculate the energy corresponding to the emission of the resulted anion of Q molecule. The spectral feature at 1.69 eV observed only in the FL spectrum of Q hydrate is attributed to the Q anion FL emission.

Abundant Lithiophilic VO2/V8C7 Heterostructures Boost Charge Transfer toward High‐Rate Lithium Storage

AbstractThe construction of a heterogeneous structure on an electrode can enhance its absorption energy, thereby improving ionic diffusion and reaction kinetics. Herein, hyperdispersed VO2/V8C7 nano‐heterostructures anchored on carbon nanofibers (VO2/V8C7@CNF), which are further utilized as a lithium anode are successfully developed. The self‐supported VO2/V8C7@CNF electrode features a synergistic effect, resulting from its well‐dispersed nano‐heterostructure, induced hetero‐interfacial electric field, and conspicuous lithiophilicity. This anode thus facilitates rapid Li+ ions diffusion and charge transfer, resulting in high‐rate performance and uniform Li deposition. It exhibits a reversible specific capacity of as high as 674.8 mA h g−1 at a current density of 0.1 A g−1 and maintains a high‐rate capability of 205.3 mA h g−1 at a current density of as high as 5.0 A g−1 even after undergoing 1000 charge/discharge cycles. The Li‐ion nucleation overpotential on this anode is significantly reduced to 27 mV. The hyperdispersed nano‐heterostructure strategy offers a universal blueprint for the fabrication of high‐performance anodes not only for lithium and other batteries.

Enhanced heterogeneous Fenton catalysis by carbon nanotube-loaded Mn doped FeS2 catalysts for pollutant degradation: Co-enhancement effect of Fe-S-Mn and Fe-S-C linkages

Recently, pyrite (FeS2) has been discovered as a promising heterogeneous Fenton catalyst due to the excellent generation of Fe(II). However, the limited inherent catalytic efficiency and poor stability hinder its wide application in wastewater treatment. Herein, a novel carbon nanotube-loaded Mn-doped FeS2 (Mn-FeS2/MWCNT) catalyst was synthesized for high radical production and durable Fenton catalysis. The optimized Mn-FeS2/MWCNT exhibited 100 % of bisphenol A elimination within 15 min, which was ∼174- and ∼20-fold than that of FeS2 and FeS2/MWCNT, respectively, and Mn-FeS2/MWCNT demonstrated remarkable stability after five cycles (less than 0.8 mg/L Fe leaching in each cycle). The generation of hydroxyl radicals (OH) and superoxide radicals (O2−) was enhanced with Mn doping and the introduction of MWCNTs. Mechanistic studies and DFT calculations revealed that Mn doping tuned the electron density between Fe and Mn in the Fe–S–Mn linkage, further improving the H2O2 absorption energy on the Mn-FeS2 surface for radical generation. Introducing MWCNTs improved the reactivity and stability of the catalyst by electron transfer of the Fe–S–C bond. This work determined the co-enhancement effect of metal sulfur links and sulfur carbon bonds on pyrite-based materials and provides a promising catalyst for wastewater remediation.

Post O2 Plasma-Induced Fabrication of 1T-WS2/a-WO3 Heterostructure for Superior Hydrogen Evolution Reaction Electrocatalysts Via Hydrogen Spillover

2D transition metal dichalcogenide (TMDC) group has been widely spotlighted as hydrogen evolution reaction (HER) electrocatalysts to replace the conventional Pt electrocatalyst due to their distinctive features of robustness, low cost, and accessibility to structural modification. However, the electrochemical activity of TMDC materials is mostly originated from its exposed edge sites, whereas its basal plane is relatively inert. There have been attempts to increase the relative fraction of active edge sites in the basal plane or employ the phase transition from semiconductive 2H phase to metallic 1T phase. The practical uses have been restricted compared to nobel metal Pt.Plasma engineering is a facile method to functionalize their basal plane and generate vacancies into the lattice as active sites to improve electrocatalytic activity. In our previous works, MoS2 and WS2 has been synthesized to have abundant defects with maximized active edge sites to impart superior HER performance by employing Ar+H2S plasma treatment on tungsten (W) thin metal film with a thickness of 1 nm. However, to surpass the intrinsic electrochemical properites, we introduce 1T-WS2/a-WO3 (WSO) heterostructure via post O2 plasma treatment by exploiting a plasma enhanced-chemical vapor deposition (PE-CVD). There has been a limitation in obtaining the best electrocatalytic performances from the plasma assisted 1T-WS2 films because of its much lower hydrogen affinity of 1T-WS2. On the contrary, tungsten trioxide (WO3) shows strong hydrophilic property in that W atomic site of WO3 can easily absorb H2O. In this regard, 1T-WS2 with hydrophilic amorphous WO3 (a-WO3) can have the outstanding HER activity by inducing hydrogen spillover effect that is a hydrogen transport phenomenon from a-WO3 to 1T-WS2. a-WO3, which has relatively stronger hydrogen affinity, plays an important role in transferring the absorbed hydrogen to 1T-WS2 as active sites. As a result, the HER performance of WSO thin film can be optimized by means of controlling the amount of a-WO3 depending on the post O2 plasma treatment time. It was also confirmed from density functional theory (DFT) calculation that the hydrogen movement on the WSO surface related to hydrogen absorption energy difference between 1T-WS2 and WO3.

Characterization of Various Stainless Steels Containing Gadolinium as Thermal Neutron Absorbing and Shielding Materials

Developing next-generation thermal-neutron-shielding and -absorbing materials for the safe storage and transportation of spent nuclear fuel is a topic of active research in academia. Gadolinium (Gd) boasts superior neutron absorption capacity compared with other nuclei. Consequently, it has garnered significant attention as a potential replacement for boron in spent nuclear fuel (SNF) applications. In this study, the austenitic stainless steels 304 and 316 and the duplex stainless steel 5A were reinforced with 2 wt.% of gadolinium to explore their thermal-neutron-absorbing efficiency. Their properties were then compared with commercial-grade borated stainless steel, as per ASTM standard A887. After the inclusion of Gd, both the yield strength and ultimate tensile strength of the alloys slightly increased, which was attributed to the evenly distributed Gd intermetallics within the matrix. However, the elongation rate was reduced. The Charpy impact absorption energy also decreased. The influence of the Gd intermetallic was further explored by examining the fractography. While the corrosion resistance of the alloy slightly diminished after the addition of Gd, its neutron absorption capacity demonstrated superior performance, especially when the Gd content was equivalent to that of boron. Although most properties of the experimental alloy deteriorated after the Gd addition, they still outperformed commercial borated stainless steel, suggesting that this alloy might be a promising candidate for SNF applications.

Small is Beautiful: Electronic Origin and Synthetic Evolution of Single-Benzene Fluorophores.

ConspectusSingle-benzene fluorophores (SBFs) are small molecules that produce visible light by using only one benzene ring as the sole aromatic core. This Account centers around the chemistry of a new class of SBF that we accidentally discovered but rationally developed and refined afterward. In a failed experiment that took an unintended reaction pathway, we encountered the bright green fluorescence of ortho-diacetylphenylenediamine (o-DAPA). Despite its uninspiring look, reminiscent of textbook examples of simple benzene derivatives, this molecule had neither been synthesized nor isolated before. This discovery led to our studies on the larger DAPA family, including isomeric m-DAPA and p-DAPA. Remarkably, p-DAPA is the lightest red fluorophore, with a molecular weight of only 192. While o- and p-DAPA are emissive, m-DAPA rapidly undergoes internal conversion, facilitated by sequential proton transfer reactions in the excited state.Leveraging the synthetic utility of the amine group, we carried out straightforward single-step modifications to create a full-color SBF library from p-DAPA as the common precursor. During the course of the investigation, we made another fortuitous discovery. With increasing acidity of the N-H group, the excited-state intramolecular proton transfer reaction is promoted, opening up additional pathways for emission to occur at even longer wavelengths. Tipping the balance between the two excited-state tautomers enabled the first example of a single-benzene white-light emitter. We demonstrated the practical utility of these molecules in white light-emitting devices and live cell imaging.According to the particle-in-a-box model, it is difficult to expect a molecule with only one small aromatic ring to produce long-wavelength emission. SBFs rise to this challenge by exploiting electron donor-acceptor pairs around the benzene core, which lowers the energy of light absorption. However, this answers only half of the question. Where do the exceptionally large spectral shifts in the light emission of SBFs originate from? Chemists have long been curious about the molecular mechanisms underlying the dramatic spectral shifts observed in SBFs. Prevailing paradigms invoke the charge transfer (CT) between electron donor and acceptor groups in the excited state. However, without a large π-skeleton for effective charge separation, how could benzene support a CT-type excited state? Our experimental and theoretical studies have revealed that large excited-state antiaromaticity (ESAA) of the benzene core itself is responsible for this remarkable phenomenon. The core matters, not the periphery. With appropriate molecular design, large and extended π-conjugation is no longer a prerequisite for long-wavelength light emission.

Exploring the synergistic influence of Cu and Co co-doping on the optical properties of ZnO nanoparticles

In this study, we synthesized Cu and Co co-doped ZnO nanoparticles, denoted as Zn1-2xCuxCoxO (x = 0.01, 0.02, 0.03), using the sol-gel auto-combustion method. Successful integration of Cu and Co elements into the ZnO host lattice was confirmed through a comprehensive array of spectroscopic techniques. Structural analysis revealed the persistence of a hexagonal wurtzite crystal structure with some distinct microstructural variations across all samples. Alteration in lattice parameters and dislocation density strongly suggests the successful incorporation of Cu2+ and Co2+ ions within the ZnO lattice. A prominent increase in crystallite size from 27.19 nm to 33.46 nm was observed with the increase in doping concentration. Field emission scanning electron microscopy showed a combination of uniformly distributed spherical and hexagon-like structures. Furthermore, UV–Visible absorption spectra demonstrated a proportional enhancement in energy band gap from 2.14 eV for Zn0.98Cu0.01Co0.01O to 2.40 eV for Zn0.94Cu0.03Co0.03O. The Burstein−Moss effect was invoked to elucidate the observed blue shift in absorption spectra and energy band gaps, further solidifying our findings. The systematic and substantial correlation between dopant concentration and energy band gap signifies that the co-doping of Cu and Co is a viable strategy for engineering the band gap of ZnO. This collective investigation unveils the substantial potential of Cu and Co co-doping in ZnO nanoparticles for advanced optoelectronic applications, paving the way for tailored optical and photonic functionalities.

Performance of reinforced concrete elements strengthened with carbon fiber CFRP at elevated temperatures

The importance of the research topic is established by the problems that occur in structural buildings when exposed to fire accidents, where the concrete loses much part of its mechanical properties and therefore becomes out of service. Because reconstruction of damaged buildings has a high financial cost, it is necessary to focus on the restoration of damaged concrete members with performant techniques and proven efficiency in terms of increasing the strength of concrete and its resistance to high temperatures. The authors conduct a numerical investigation on the use of carbon fiber-reinforced polymer sheeting CFRP to restore various structural concrete elements such as beams, columns, and slabs damaged in fire accidents for two types of normal and high-strength concrete, in addition to studying the behavior of concrete after strengthening it with CFRP sheets. The results by showed that load capacity, stiffness index, and absorption energy index have been improved

Effect of Nb Content and Second Heat Cycle Peak Temperatures on Toughness of X80 Pipeline Steel.

The microstructure evolution and variation of impact toughness in the heat-affected zone (HAZ) of X80 pipeline steel with different Nb content under different peak temperatures in the secondary thermal cycle were studied through welding thermal simulation, the Charpy impact test, EBSD analysis, SEM observation, and TEM observation in this study. The results indicate that when the peak temperatures of the second pass were lower than Ac1, both X80 pipeline steels had high impact toughness. For secondary peak temperatures in the range of Ac1 to Ac3, both X80 pipeline steels had the worst impact toughness, mainly due to the formation of massive blocky M-A constituents in chain form on grain boundaries. When the secondary peak temperatures were higher than Ac3, both X80 pipeline steels had excellent impact toughness. Smaller grain size and higher proportions of HAGBs can effectively improve the impact toughness. Meanwhile, high Nb X80 pipeline steel had higher impact absorption energy and smaller dispersion. Adding an appropriate amount of Nb to X80 pipeline steel can ensure the impact toughness of SCCGHAZ and SCGHAZ in welded joints.

Photoluminescence properties of Eu2+‐activated thiogallate phosphors

AbstractThis work analyzes the crystal structural properties and photoluminescence properties of six Eu2+‐activated thiogallates: CaGa2S4:Eu2+, SrGa2S4:Eu2+, EuGa2S4, BaGa2S4:Eu2+, Sr2Ga2S5:Eu2+, and Eu2Ga2S5. Photoluminescence parameters such as the absorption energy (Eabs), emission energy (Eem), zero‐phonon line energy (E0), Stokes shift (ΔS), and red shift (D) are discussed. This work is the first report on the photoluminescence parameters of these six Eu2+‐activated thiogallates and therefore provides important information about these materials.

Δ-based composite models for calculating x-ray absorption and emission energies

A practical ab initio composite method for modeling x-ray absorption and non-resonant x-ray emission is presented. Vertical K-edge excitation and emission energies are obtained from core-electron binding energies calculated with spin-projected ΔHF/ΔMP and outer-core ionization potentials/electron affinities calculated with electron propagator theory. An assessment of the combined methodologies against experiment is performed for a set of small molecules containing second-row elements.

Quantum DFT studies on the drug delivery of favipiravir using pristine and functionalized chitosan nanoparticles

Considering the spread of the COVID-19 pandemic, finding new drugs along with the development of effective drug delivery methods can help in the treatment of this disease. For this reason, in this research work, the possibility of drug-delivery of Favipiravir (FP), one of the drugs approved in the treatment of COVID-19, by pristine chitosan (Chit) nanoparticles (NP), and functionalized chitosan nanoparticles with N-acylate, N-methyl, O-acetyl, and Oxazoline functional groups was studied using quantum mechanical DFT methods at B3LYP-D3(BJ)/6-311 + g(d,p) theoretical level in water medium. The QTAIM, NBO, DOS, frontier orbital, conceptual-DFT indices, and non-covalent interaction analysis were further implemented to investigate the possible interactions between FP and Chit NPs. The results show that the adsorption of FP on Chit NPs is done through the creation of hydrogen bonds, and the highest absorption energy of − 18.15 kcal/mol between pristine chitosan and FP. In the case of all functionalized Chit NPs, a decrease in the absorption energy is observed, which is more noticeable in the case of N-acylated and O-acetyl functionalize Chit NPs, and indicates the weakening of the van der Waals interactions for these cases. Considering the compatibility of Chit NPs with the human body and their non-toxicity, as well as the fact that factors such as pH, solubility, the ionic strength, and so on can be adjusted to control the release rate using the functionalized Chit NPs, it seems that the results of this work can be a comprehensive guide to design the drug delivery methods of FP drug using Chit NPs, to reduce the symptoms of COVID-19 disease.

Bulk‐Phase Grain Boundaries Regulation Enables Highly Reversible Zn Anodes for Rechargeable Aqueous Zn‐Ion Batteries

AbstractDendrites and side reactions of Zn anodes severely restrict the application of aqueous Zn‐based batteries for grid‐scale energy storage. While surface/interface modification strategies have shown some progress in improving Zn anode reversibility, they still fall short in addressing the overall regulation and intrinsic mechanisms from the bulk‐phase perspective. Herein, a bulk‐phase composite Zn/CNTs anodes fabricated by a powder‐metallurgy‐based strategy is introduced. Benefiting from the regulation of grain boundary engineering on local electric conductivity, electric field distributions, and Zn atom absorption energy, the Zn/CNTs anodes effectively suppress dendrite growth and enhance corrosion resistance during Zn stripping/plating cycles. Symmetrical cells equipped with Zn/CNT4 anodes exhibit extended cycling stability with minimal voltage hysteresis (only 22 mV). Furthermore, the full cells incorporating Zn/CNT4 with commercial MnO2 demonstrate superior rate performance and specific capacitance retention after 500 h cycling. This breakthrough opens up new avenues for optimizing metallic anodes at the bulk phase level using powder metallurgy, enabling scalable manufacturing processes, and providing valuable insights for various metal anode systems.

Characteristic analysis of bionic-induced structures with negative stiffness inspired by the growth and deformation differences of branches

Negative stiffness (NS) structures with curved beams easily experience beam fracture in small-scale designs, limiting their repeatability and energy absorption. The induced energy absorption structure (IEAS), which achieves negative stiffness by altering load transfer paths, is designed inspired by the growth and deformation of tree branches. By means of the variation method of geometric parameters, a unique asymmetric buckling deformation mode is realized in IEAS. The NS and energy absorption characteristics in IEAS are analyzed based on load distribution and major principal strain theory. Compression results demonstrate that the asymmetric buckling mode exhibits higher energy absorption and specific energy absorption compared to symmetric linear buckling, effectively improving structural toughness. Through gradient analysis of geometric parameters and comprehensive analysis of induced structure layouts, the asymmetric buckling mode is successfully implemented in multi-layer IEAS. The multi-layer IESA exhibits excellent ability of energy absorption and toughness, making it have potential applications in areas that require small-sized designs with high energy absorption capabilities.