Unique Design Concept Research Articles

A passive-tuned damper based on magnetorheological porous fabric composite

Abstract This paper proposes a novel passive-tuned magnetorheological (PTMR) damper based on developed magnetorheological (MR) porous fabric composite, in which the damping force is tuned by a permanent magnet (PM). Firstly, the influences of the porous fiber structure of composite on the suspended phase are considered, and a continuous constitutive model based on the dipole model is proposed for the first time, which can accurately predict its rheological properties. Subsequently, a stable passive damper for special conditions is designed, and the unique design concept is to achieve completely different damping characteristics for different application scenarios by adjusting the position of the PM relative to the magnetic circuit. The experimental results show that the damping force is relatively stable under specific condition, and can be adjusted within the range of 16.8–77.4 N, with a dynamic range of about 4.6. Moreover, the PTMR damper can exhibit unidirectional negative stiffness characteristic by adjusting the PM to a specific position. The PTMR damper has stable vibration reduction performance, wide dynamic range, and compact structure, which can be comparable to some conventional MR dampers.

Spatially Confined Engineering Toward Deep Eutectic Electrolyte in Metal-Organic Framework Enabling Solid-State Zinc-Ion Batteries.

Uncontrollable interfacial side reactions generated from common aqueous electrolytes, just like the hydrogen evolution reaction (HER) and dendrite growth, have severely prevented the practical application of zinc-ion batteries (ZIBs). Solid-state ZIBs are considered to be an efficient strategy by adopting high-quality solid-state electrolytes (SSEs). Here, by confining deep eutectic electrolyte (DEE) into the nanochannels of metal-organic framework (MOF)-PCN-222, a stable DEE@PCN-222 SSE with internal Zn2+ transport channels was obtained. A distinctive ion-transport network composed of DEE and PCN-222 in the interior of DEE@PCN-222 realizes the efficient Zn2+ conduction, contributing to high ionic conductivity of 3.13×10-4 S cm-1 at room temperature, low activation energy of 0.12 eV, and a high Zn2+ transference number of 0.74. Furthermore, experimental and theoretical investigations demonstrate that DEE@PCN-222 with its unique channel structure could homogeneously regulate the Zn2+ distribution and effectively alleviate the side reactions. Highly reversible Zn plating/stripping performance of 2476 h can be realized by the SSE. The solid-state ZIBs show a specific capacity of 306 mAh g-1 and display cycling stability of 517 cycles. This unique design concept provides a new perspective in realizing the high-safety and high-performance ZIBs.

Spatially Confined Engineering Toward Deep Eutectic Electrolyte in Metal‐Organic Framework Enabling Solid‐State Zinc‐Ion Batteries

AbstractUncontrollable interfacial side reactions generated from common aqueous electrolytes, just like the hydrogen evolution reaction (HER) and dendrite growth, have severely prevented the practical application of zinc‐ion batteries (ZIBs). Solid‐state ZIBs are considered to be an efficient strategy by adopting high‐quality solid‐state electrolytes (SSEs). Here, by confining deep eutectic electrolyte (DEE) into the nanochannels of metal‐organic framework (MOF)‐PCN‐222, a stable DEE@PCN‐222 SSE with internal Zn2+ transport channels was obtained. A distinctive ion‐transport network composed of DEE and PCN‐222 in the interior of DEE@PCN‐222 realizes the efficient Zn2+ conduction, contributing to high ionic conductivity of 3.13×10−4 S cm−1 at room temperature, low activation energy of 0.12 eV, and a high Zn2+ transference number of 0.74. Furthermore, experimental and theoretical investigations demonstrate that DEE@PCN‐222 with its unique channel structure could homogeneously regulate the Zn2+ distribution and effectively alleviate the side reactions. Highly reversible Zn plating/stripping performance of 2476 h can be realized by the SSE. The solid‐state ZIBs show a specific capacity of 306 mAh g−1 and display cycling stability of 517 cycles. This unique design concept provides a new perspective in realizing the high‐safety and high‐performance ZIBs.

Hyperloop New Mode of Transportation

Today conventional mode of transportation is rail, road, water, and air. These modes of transport are relatively slow and expensive or a combination of relatively slow and expensive. Hyper loop is latest mode of transportation which is fast and inexpensive to change the pattern of transportation. Similar to Linux, hyper loop is also open and unique design concept. By bringing this concept to reality, it will help people to travel from one city to another city in a very small time and also at a low cost. The hyper loop capsule would accelerate with the help of linear electric motor and traverse through the tube at a high speed. By using passive magnetic levitation or air bearing, capsule will run above their track. Hyper loop consists of a low-pressure tube with capsules that are travelled at low and high speed throughout the length of the tube. The capsules are supported with the help of cushion of air. To accelerate the capsules the magnetic linear accelerator is fitted at various stations on the hyperloop tube. To enter and exit the passengers the passage may be left either at the end of the tube or branches along the tube length. Let's see how the hyperloop change mode of transportation.

Hyperbranched Vitrimer for Ultrahigh Energy Dissipation.

Polymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate-2-(4-ethenylphenyl)-5,5-dimethyl-1,3,2-dioxaborinane) P(HMA-co-ViCL) copolymers. The -type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high-performance HBV damping materials. We found that P(HMA-co-ViCL) 20k-40-60 HBV exhibited ultrahigh energy-dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials.

Hyperbranched Vitrimer for Ultrahigh Energy Dissipation

AbstractPolymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate‐2‐(4‐ethenylphenyl)‐5,5‐dimethyl‐1,3,2‐dioxaborinane) P(HMA‐co‐ViCL) copolymers. The ‐type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high‐performance HBV damping materials. We found that P(HMA‐co‐ViCL) 20k‐40‐60 HBV exhibited ultrahigh energy‐dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials.

Liquid metal in prohibiting polysulfides shuttling in metal sulfides anode for sodium-ion batteries

Metal sulfides are a class of promising anode materials for sodium-ion batteries (SIBs) owing to their high theoretical specific capacity. Nevertheless, the reactant products (polysulfides) could dissolve into electrolyte, shuttle across separator, and react with sodium anode, leading to severe capacity loss and safety concerns. Herein, for the first time, gallium (Ga)-based liquid metal (LM) alloy is incorporated with MoS2 nanosheets to work as an anode in SIBs. The electron-rich, ultrahigh electrical conductivity, and self-healing properties of LM endow the heterostructured MoS2-LM with highly improved conductivity and electrode integrity. Moreover, LM is demonstrated to have excellent capability for the adsorption of polysulfides (e.g., Na2S, Na2S6, and S8) and subsequent catalytic conversion of Na2S. Consequently, the MoS2-LM electrode exhibits superior ion diffusion kinetics and long cycling performance in SIBs and even in lithium/potassium-ion battery (LIB/PIB) systems, far better than those electrodes with conventional binders (polyvinylidene difluoride (PVDF) and sodium carboxymethyl cellulose (CMC)). This work provides a unique material design concept based on Ga-based liquid metal alloy for metal sulfide anodes in rechargeable battery systems and beyond.

Volatility-based diversity awareness for distributed data storage of Mobile Crowd Sensing

With the widespread utilization of sensors and the rapid development of Mobile Crowd Sensing (MCS), the framework of distributed data storage, which makes use of the limited storage capacity of sensing devices, is providing an alternative to cloud-based data storage. Since the construction of the distributed storage framework for MCS has to be completed by Compressed Sensing (CS) theory, a reasonable measurement allocation becomes a no-brainer if we want to obtain more recovery precision of data without wasting measurement resources. To more efficiently address the above problems, we present a novel strategy of Volatility-Based Diversity Awareness for CS measurement allocation called VBDA, which collectively achieves lower computational complexity, adaptive sampling rate allocation for non-visual data, and high-quality reconstruction. We first process the target monitoring region in blocks. Then, we calculate the degree of data diversity of each area using the volatility, which is used to assess the importance of the different areas. Worthy note, based on the volatility calculation, we can obtain the magnitude of the variation in diversity that is only present in the real data, even when using very ambiguous recovered data. This is primarily due to the volatility unique design concept, which attempts to offset partially identical errors in adjacent recovered data using volatility calculations. Finally, to rationally allocate measurement resources, a volatility-based sampling rate allocation scheme is proposed. We further provide an implementation for practical deployments of VBDA in various related contexts. Numerous experimental show that the VBDA performs excellently. In comparison to the current state-of-the-art strategy, it improves data recovery accuracy by 12.2% without the use of any prior knowledge, while being adaptable to many different distribution types of data.

Heterointerface engineering of rhombic Rh nanosheets confined on MXene for efficient methanol oxidation

Although metallic rhodium (Rh) is regarded as a promising platinum-alternative anode catalyst of direct methanol fuel cell (DMFC), the conventional “particle-to-face” contact model between Rh and matrix largely limits the overall electrocatalytic performance due to their insufficient cooperative effects. Herein, we report a controllable and robust heterointerface engineering strategy for the bottom-up fabrication of rhombic Rh nanosheets in situ confined on Ti3C2Tx MXene nanolamellas (Rh NS/MXene) via a convenient stereoassembly process. This unique design concept gives the resulting 2D/2D Rh NS/MXene heterostructure intriguing textural features, including large accessible surface areas, strong “face-to-face” interfacial interactions, homogeneous Rh nanosheet distribution, ameliorative electronic structure, and high electronic conductivity. As a consequence, the as-prepared Rh NS/MXene nanoarchitectures exhibit exceptional electrocatalytic methanol oxidation properties in terms of a large electrochemically active surface area of 126.2 m2 g−1Rh, a high mass activity of 1056.9 mA mg−1Rh, and a long service life, which significantly outperform those of conventional particle-shaped Rh catalysts supported by carbon black, carbon nanotubes, reduced graphene oxide, and MXene matrixes as well as the commercial Pt nanoparticle/carbon black and Pd nanoparticle/carbon black catalysts with the same noble metal loading amount. Density functional theory calculations further demonstrate that the direct electronic interaction at the well-contacted 2D/2D heterointerfaces effectively enhances the adsorption energy of Rh nanosheets and induces a left shift of the d-band center, thereby making the Rh NS/MXene configuration suffer less from CO poisoning. This work highlights the importance of rational heterointerface design in the construction of advanced noble metal/MXene electrocatalysts, which may provide new avenues for developing the next-generation DMFC devices.

Leveraging a coarse yet strong matrix in L12-strengthened high-entropy alloy through simplified thermomechanical processing

High-entropy alloys (HEAs), characterized by their unique design concept without a distinct major element, offer a versatile alloy design window while ensuring outstanding properties. In this study, the FeCoCrNi–AlTi alloy system, which exploits L12 phase with slow ripening kinetics due to the coherent interface with the FCC phase, has been researched to increase strength via precipitation. This system has been widely studied to improve mechanical properties through microstructure optimization, especially in a direction that suppresses discontinuous precipitation while enhancing strength. Herein, we propose a novel processing method utilizing hot-rolling followed by direct aging for a newly designed (FeCoNi)79.5Cr10.5Al5Ti5 (at%) HEA. The coarse yet strong FCC matrix, generated via hot-rolling, proves advantageous in the subsequent direct aging, as revealed through careful microstructural characterization of both continuous and discontinuous precipitates. A high yield strength of 1065.5 ± 0.4 MPa, a uniform elongation of 14.2 ± 0.0%, and a total elongation of 27.5 ± 0.9% are simultaneously achieved, due to maintaining high dislocation density and promoting continuous precipitation, whereas discontinuous precipitation is suppressed and occupies little area fraction of ∼8%. Careful discussions are provided regarding the impact of the newly proposed processing on the precipitation mechanism, and how the resulting microstructure influences the strengthening mechanisms. This work demonstrates the effectiveness of a simplified thermomechanical process, providing valuable insights into microstructure control in HEAs.

Frontier Molecular Orbital Engineering of Aromatic Donor Fusion: Modularly Constructing Highly Efficient Narrowband Yellow Electroluminescence.

The development of high-performance multiple resonance thermally activated delayed fluorescence (MR-TADF) materials with narrowband yellow emission is highly critical for various applications in industries, such as the automotive, aerospace, and microelectronic industries. However, the modular construction approaches to expeditiously access narrowband yellow-emitting materials is relatively rare. Here, a unique molecular design concept based on frontier molecular orbital engineering (FMOE) of aromatic donor fusion is proposed to strategically address this issue. Donor fusion is a modular approach with a "leveraging effect"; through direct polycyclization of donor attached to the MR parent core, it is facile to achieve red-shifted emission by a large margin. As a result, two representative model molecules, namely BN-Cz and BN-Cb, have been constructed successfully. The BN-Cz- and BN-Cb-based sensitized organic light-emitting diodes (OLEDs) exhibit bright yellow emission with peaks of 560 and 556 nm, full-width at half-maxima (fwhm's) of 49 and 45 nm, Commission Internationale de L'Eclairage coordinates of (0.44, 0.55) and (0.43, 0.56), and maximum external quantum efficiencies (EQEs) of 32.9% and 29.7%, respectively. The excellent optoelectronic performances render BN-Cz and BN-Cb one of the most outstanding yellow-emitting MR-TADF materials.

Subversion and PersistenceAnalysis of Balenciaga's Innovation Strategy

Balenciaga is a world-renowned luxury brand, and its unique design style and profound historical background make its position in fashion unshakable. However, like all innovators, Balenciagas design style is not always understood and accepted by people. This paper will discuss how Balenciaga maintains its influence in the world fashion through subversive innovation and continuous innovation, and analyze peoples different reactions to its innovative design. The author will deeply analyze and understand the history, design philosophy and specific works of Balenciaga. At the same time, we will combine personal observation and experience to evaluate its innovative way and influence. Balenciagas innovation is mainly manifested in subversive innovation and continuous innovation. It redefines fashion by breaking the tradition, while maintaining its unique brand identity and design concept. Although some of Balenciagas designs may be regarded as ugly in the eyes of the public, it is the embodiment of its innovative spirit and the source of its lasting influence in the fashion world.

A DNA-polymer hybrid nanocomplex based bi-adjuvant vaccine for tumor immunotherapy

The immunosuppressive tumor microenvironment (TME) seriously impedes the cancer immunotherapy; Toll-like receptors (TLRs) agonists combination is emerging as vaccine adjuvant in reprogramming tumor immune microenvironment. Herein, we develop a supramolecular DNA-polymer hybrid nanocomplex-based bi-adjuvant vaccine for tumor immunotherapy. In the nanocomplex, the co-assembly of TLR9 agonist (CpG) and TLR7 agonist (loxoribine) was achieved via dynamic DNA assembly and boron chemistry. Poly-N-isopropyl acrylamide (PNIPAM) served as the framework of the nanocomplex, and meanwhile, designer DNA sequences were introduced as cross-linkers in the nanoframework to trigger the hybridization chain reaction (HCR)-based assembly of CpG sequences containing hairpins. The polymer framework was decorated with phenylboronic acid to capture and release loxoribine via reversible formation of cyclic boric acid ester. A lipid shell was coated on the outside of the CpG and loxoribine co-loaded nanocomplex to prevent the leakage of loxoribine in plasma. After intravenous injection, the nanocomplex was internalized by the tumor-associated immune cells via lysosomal related pathways. CpG and loxoribine synergistically stimulated TLR9 and TLR7 receptors, thus leading to the conversion of suppressive M2 macrophage to active M1 macrophage, maturation of dendritic cells, and activation of T cells. The dual activation of TLR9 and TLR7 effectively reprogramed tumor immune microenvironments in vivo, wherein robust CD8+ T cell response and efficient tumor regression were achieved. This work provides a unique design concept for the TLR agonists combination-based nanovaccine for tumor immunotherapy.

An Ultrahigh-Capacity Dual-Ion Battery Based on a Free-Standing Graphite Paper Cathode and Flower-Like Heterojunction Anode of Tin Disulfide and Molybdenum Disulfide.

Dual-ion batteries have been considered as a competitive energy-storage device. However, owing to the lack of suitable high-capacity density and rapid-charging electrode materials, designing a cost-effective and high-performance dual-ion battery is still a great challenge. Herein, an ultrahigh-capacity dual-ion battery is constructed based on a carbon-nanotubes (CNTs) containing SnS2 -MoS2 @CNTs heterojunction anode and highly crystalline free-standing graphite paper serves as cathode. The SnS2 -MoS2 @CNTs heterojunction consisting of ultrathin nanosheets was prepared via a facile two-step hydrothermal method and shows flower-like morphology and high crystallinity. Benefiting from the unique design concept, the graphite paper/SnS2 -MoS2 @CNTs dual-ion battery delivers a high capacity of 274.2 mAh g-1 at 100 mA g-1 and has an outstanding capacity retention of 95 % after 300 cycles under 400 mA g-1 . Even at a high current density of 2 A g-1 the battery still retains a considerable capacity of 112.3 mAh g-1 . More importantly, the battery shows an extremely low self-discharge of 0.006 % h-1 after resting for 24 h. Characterization using SEM and XRD further demonstrate the excellent cycling stability and good reversibility. Consequently, this constructed dual-ion battery could be a promising energy storage device and provide new insights for the design of high-performance dual-ion batteries.

The electrothermal color-changing fabric based on high-sensitivity thermochromic microcapsules

High sensitivity including low color hydrolysis and a narrow temperature range of color-changing is important to thermochromic microcapsules. However, it is a challenge for conventional ternary thermochromic systems to realize the fast change of colors. A new class of high-sensitivity microcapsules and electrothermal color-changing fabrics were designed and synthesized by introducing CNTs into thermochromic systems via microencapsulation and coating technology. The high sensitivity was attributed to the enhanced filler CNTs and binary core phase change materials (1-Tetradecanol/1-Octadecanol). Moreover, the dosage amount of CNTs, core-to-shell ratios, and particle size on the temperature sensitivity of microcapsules were investigated. From the results, the optimized microcapsules with regular spherical shape exhibited a narrow color-change temperature range of 30–35 ℃ and low color hydrolysis of 11 ℃. As the core wall ratio increased from 1:1–3:1, the color change temperature range of microcapsules became narrower and the color hydrolysis was lower. According to the phase change behaviors, thermochromic microcapsules with a melting enthalpy of 70.64 J/g performed a good thermal regulation capacity. Furthermore, the reversible thermochromic performance of obtained microcapsules remained stable through 500 thermal cycles, demonstrating excellent thermal cycling stability. Combining the obtained microcapsules and electrothermal fabrics, highly sensitive electro-thermochromic (ETC) fabrics by voltage were prepared. Under the supplied voltage of 6 V, the ETC fabrics exhibited outstanding cyclic electrothermal color-changing performance. This unique design concept for high-sensitivity ETC fabrics has great potential applications in personal thermal management, the cooling of electronic devices, visible displays, and so on.

Recent Advances for High-Entropy based Layered Cathodes for Sodium Ion Batteries.

In recent years, layered oxides have been extensively studied as promising cathode materials for sodium ion batteries. However, layered oxides undergo complex phase transitions during charge-discharge process, which adversely affects the electrochemical performance. High-entropy layered oxides as a unique design concept can effectively improve the cycling performance of cathode materials by virtue of the 2D ion migration channels between the layers. Based on the concepts of high-entropy and layered oxides, this paper reviews the research status of high-entropy layered oxides in the field of sodium-ion batteries, focusing on the connection between high-entropy and layered oxide phase transitions during electrochemical charging and discharging. Finally, the advantages of layered cathode materials based high-entropy are summarized, and the opportunities and challenges of future high-entropy layered materials are proposed.

Microstructure and Properties of NiCoCrAlTi High Entropy Alloy Prepared Using MA-SPS Technique

In this study, Ni35Co35Cr12.6Al7.5Ti5Mo1.68W1.39Nb0.95Ta0.47 high entropy alloy (HEA) was prepared using mechanical alloying (MA) and spark plasma sintering (SPS) based on the unique design concept of HEAs and third-generation powder superalloys. The HEA phase formation rules of the alloy system were predicted but need to be verified empirically. The microstructure and phase structure of the HEA powder were investigated at different milling times and speeds, with different process control agents, and with an HEA block sintered at different temperatures. The milling time and speed do not affect the alloying process of the powder and increasing the milling speed reduces the powder particle size. After 50 h of milling with ethanol as PCA, the powder has a dual-phase FCC+BCC structure, and stearic acid as PCA inhibits the powder alloying. When the SPS temperature reaches 950 °C, the HEA transitions from a dual-phase to a single FCC phase structure and, with increasing temperature, the mechanical properties of the alloy gradually improve. When the temperature reaches 1150 °C, the HEA has a density of 7.92 g cm-3, a relative density of 98.7%, and a hardness of 1050 HV. The fracture mechanism is one with a typical cleavage, a brittle fracture with a maximum compressive strength of 2363 MPa and no yield point.

Ultra-thin hierarchical porous carbon coated metal phosphide self-assembled efficient tri-functional electrodes for overall water splitting and rechargeable zinc-air batteries

Highly efficient and stable trifunctional electrocatalysts with controllable nanostructures toward hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) are extraordinarily important for the sustainable energy development. Here we report a general and facile synthetic method for designing a hierarchically porous Ni-foam-based self-supported electrode (NPO/NixPy@NF-HPCs). Based on its unique design concept, the NPO/NixPy@NF-HPCs shows high tri-functional catalytic activities. As a result, the NPO/NixPy@NF-HPCs-based rechargeable zinc-air battery (ZAB) and water splitting device exhibit high power density up to 377 mW cm−2 and low cell voltage of 1.52 V@10 mA cm−2, respectively. Notably, the mapping between the stability and the quasi-in situ characterization demonstrates that it is a reliable method to improve electrode stability by establishing a stable outer carbon layer to avoid the oxidation of internally active sites. This work is promised to provide a viable new approach to developing efficient and low-cost carbon-supported phosphate tri-functional electrode.

Structures and room-temperature magnetic properties of entropy-modulated Gd<sub>2</sub>Co<sub>17</sub> based intermetallic compounds

<sec>The entropy-modulated material has been a hot topic due to its unique design concept and excellent properties. However, previous studies of entropy-modulated materials mainly focused on the alloys with simple face-centered cubic, or body-centered cubic, or hexagonal close-packed structures. In this work, the design concept of entropy-modulation is introduced into Gd<sub>2</sub>Co<sub>17</sub> based intermetallic compound, and the effect of high configuration entropy on the structural stabilization and room-temperature magnetic properties of Gd<sub>2</sub>Co<sub>17</sub> based intermetallic compound are studied systematically.</sec><sec>The samples are prepared by vacuum Arc melting technology in an ultrahigh-purity Ar atmosphere and followed by annealing at 1000 ℃ for 8 days and finally by quenching in cool water. The fine powders are prepared by grinding the ingots in an agate mortar. The powder XRD and SEM-EDS are used to check the crystal structures and chemical compositions. To study the magnetic properties, the column-like samples are prepared by mixing the fine powder and epoxy with a weight ratio of 1∶1, and then aligned under an applied field of 1 T at room temperature.</sec><sec>The high configuration entropy is found to play an important role in the structural stabilization and magnetic properties of Gd<sub>2</sub>Co<sub>17</sub> based medium- and high-entropy intermetallic compounds. The XRD patterns and Rietveld structural refinement results confirm that all the samples are single-phase. The structure depends on the effective atomic radius <i>R</i><sub><i>A</i></sub>, the structure of entropized Gd<sub>2</sub>Co<sub>17</sub> based intermetallics can be stabilized into rhombohedral Th<sub>2</sub>Zn<sub>17</sub>-type with <i>R</i><sub>A </sub>> 1.416 or hexagonal Th<sub>2</sub>Ni<sub>17</sub>-type with <i>R</i><sub>A<i> </i></sub>< 1.4105. According to thermodynamic calculations of entropized Gd<sub>2</sub>Co<sub>17</sub> intermeatllics, the atomic radius difference Δ<i>r</i> ranges from 0.55% to 1.81%, and the mixing enthalpy <inline-formula><tex-math id="M3">\begin{document}$ \Delta {{\boldsymbol{H}}}_{{\rm{m}}{\rm{i}}{\rm{x}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20221995_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20221995_M3.png"/></alternatives></inline-formula> is corresponding to 0 for the rare earth site, –4 to –1 kJ/mol for the transition metal site, and –8.54 to –5.13 kJ/mol between rare earth and transition metal sites. It is suggested that all the thermodynamic parameters meet the criteria for the formation of single-phase medium- and high-entropy intermetallic compounds. The configuration entropy changes from 0.69R to 1.39R. The room temperature magnetic properties are significantly improved by the modulation of entropized design at rare earth and transition metal sublattices. The entropization enhances the saturation moments of all samples, which can be explained with a modified magnetic valence model. The value of <inline-formula><tex-math id="M4">\begin{document}${N}_{{\rm{sp}}}^{\uparrow }$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20221995_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="10-20221995_M4.png"/></alternatives></inline-formula> (the number of the electrons in the unpolarized sp conduction bands) increases from 0.3 to 0.4 after entropization, the indirect interaction between rare earth and transition metal sublattice is increased, the spin moment of s conducting electron as a medium of two sublattices is enhanced, and the magnetic moment is increased. The entropization also induces magnetic anisotropy to transform from basal plane to easy axis for the entropized design at transition metal sublattice and the coercivity of rare earth to increase.</sec>

Nanoflower-like high-entropy Ni-Fe-Cr-Mn-Co (oxy)hydroxides for oxygen evolution.

High-entropy materials (HEMs) have potential application value in electrocatalytic water splitting because of their unique alloy design concept and significant mixed entropy effect. Here, we synthesize a high-entropy Ni-Fe-Cr-Mn-Co (oxy)hydroxide on nickel foam (NF) by a solvothermal method. The flower-like structure of FeNiCrMnCoOOH/NF can provide abundant active sites, thus improving the oxygen evolution reaction (OER) activity. In 1 M KOH, the FeNiCrMnCoOOH/NF shows an ultra-low overpotential (η10) of 201 mV for the OER, superior to FeNiCrMnAlOOH/NF, FeNiCrMnCuOOH/NF, FeNiCrMnMoOOH/NF, and FeNiCrMnCeOOH/NF. In addition, it exhibits a low η10 of 223 mV in 0.5 M NaCl + 1 M KOH and excellent stability. Electrochemical impedance spectroscopy measurements indicate that the synergistic effect between multiple metals accelerates charge transfer, while in situ Raman measurements reveal that NiOOH is a key active species for the OER. This work is of great significance for the construction of high-entropy (oxy)hydroxides for seawater electrolysis.