High-Efficiency and Stable Colloidal One-Dimensional Core/Shell Nanorod Light-Emitting Diodes.

Anisotropic nanocrystals such as nanorods (NRs) display unique linearly polarized emission, which is expected to break the external quantum efficiency (EQE) limit of quantum dot-based light-emitting diodes (LEDs). However, the progress in achieving a higher EQE using NRs encounters several challenges, primarily involving a low photoluminescence quantum yield (PLQY) of NRs and imbalanced charge injection in NR-LEDs. In this work, we investigated NR-LEDs based on CdSe/CdZnS/ZnS rod-in-rod NRs with a high PLQY and higher linear polarization compared to those of dot-in-rod NRs. The balanced charge injection is achieved using ZnMgO nanoparticles as the electron transport layer and poly-TPD {poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine]} as the hole transport layer. Therefore, the NR-LEDs exhibit a maximum EQE of 21.5% and a maximum luminance of >120 000 cd/m2 owing to the high level of in-plane transitions with a dipole moment of 90%. The NR-LEDs also have greatly inhibited droop in EQE under a high current density as well as outstanding operation lifetime and cycle stability.

Optimization of Mechanical and Thermoelectric Properties of SnTe-Based Semiconductors by Mn Alloying Modulated Precipitation Evolution.

Multiscale defects engineering offers a promising strategy for synergistically enhancing the thermoelectric and mechanical properties of thermoelectric semiconductors. However, the specific impact of individual defects, in particular precipitation, on mechanical properties remains ambiguous. In this work, the mechanical and thermoelectric properties of Sn1.03- xMnxTe (x = 0-0.30) semiconductors are systematically studied. Mn-alloying induces dense dislocations and Mn nano-precipitates, resulting in an enhanced compressive strength with x increased to 0.15. Quantitative calculations are performed to assess the strengthening contributions including grain boundary, solid solution, dislocation, and precipitation strengthening. Due to the dominant contribution of precipitation strengthening, the yield strength of the x = 0.10 sample is improved by ≈74.5% in comparison to the Mn-free Sn1.03Te. For x ≥ 0.15, numerous MnTe precipitates lead to a synergistic enhancement of strength-ductility. In addition, multiscale defects induced by Mn alloying can scatter phonons over a wide frequency spectrum. The peak figure of merit ZT of ≈1.3 and an ultralow lattice thermal conductivity of ≈0.35 Wm-1 K-1 are obtained at 873 K for x = 0.10 and x = 0.30 samples respectively. This work reveals tha precipitation evolution optimizes the mechanical and thermoelectric properties of Sn1.03- xMnxTe semiconductors, which may hold potential implications for other thermoelectric systems.

Bimetallic Sulfide Hollow Nanocubes Heterostructure Promotes Dual Coupling of Conversion and Alloying/Dealloying Reactions to Achieve Durable Potassium-Ion Battery Anode.

Conversion and alloying-type transitional metal sulfides have attracted significant interests as anodes for Potassium-ion batteries (PIBs) and Sodium-ion batteries (SIBs) due to their high theoretical capacities and low cost. However, the poor conductivity, structural pulverization, and high-volume expansions greatly limit the performance. Herein, Co1-xS/ZnS hollow nanocube-like heterostructure decorated on reduced graphene oxide (Co1-xS/ZnS@rGO) composite is fabricated through convenient hydrothermal and post-heat vulcanization techniques. This unique composite can provide a more stable conductive network and shorten the diffusion length of ions, which exhibits a remarkable initial charge capacity of 638.5 mA h g-1 at 0.1 A g-1 for SIBs and 606 mA h g-1 at 0.1 A g-1 for PIBs, respectively; It is worth noting that the composite presents remarkable long stable cycle performance in PIBs, which initially delivered 274 mA h g-1 and sustained the charge capacity up to 245 mA h g-1 at high current density of 1 A g-1 after 2000 cycles. A series of in situ/ex situ detections and first principle calculations further validate the high potassium ions adsorption ability of Co1-xS/ZnS anode materials with high diffusion kinetics. This work will accelerate the fundamental construction of bimetallic sulfide hollow nanocubes heterostructure electrodes for energy storage applications.

Controlled Synthesis of SnO2 Nanostructures as Alloy Anode via Restricted Potential Toward Building High-Performance Dual-Ion Batteries with Graphite Cathode.

Dual-ion batteries (DIBs) are considered one of the promising energy storage devices in which graphite serves as a bi-functional electrode, i.e., anode and cathode in the aprotic organic solvents. Unlike conventional lithium-ion batteries (LIBs), DIBs reversibly store the cations and anions in the anode and cathodes during redox reactions, respectively. The electrolyte is a source for both cations and anions, so the choice of electrolyte plays a vital role. In the present work, the synthesis of SnO2 nanostructures is reported as a possible alternative for graphite anode, and the Li-storage performance is optimized in half-cell (Li/SnO2 ) assembly with varying amounts of conductive additive (acetylene black) and limited working potential (1 V vs Li). Finally, a DIB using recovered graphite (RG) fabricated from spent LIB as a cathode and SnO2 nanostructures as an anode under balanced loading conditions. Prior to the fabrication, both electrodes are pre-cycled to eliminate irreversibility. An in-situ impedance study has been employed to validate the passivation layer formation during the charge-discharge process. The high-performance SnO2 /RG-based DIB delivered a maximum discharge capacity of 380 mAh g-1 . The electrochemical performance of DIB has been assessed by varying temperature conditions to evaluate their suitability in different climatic conditions.

A Universal Approach for Controllable Synthesis of Homogeneously Alloyed PtM Nanoflowers toward Enhanced Methanol Oxidation.

Platinum (Pt)-based alloys have received considerable attention due to their compositional variability and unique electrochemical properties. However, homogeneous element distribution at the nanoscale, which is beneficial to various electrocatalytic reactions, is still a great challenge. Herein, a universal approach is proposed to synthesize homogeneously alloyed and size-tunable Pt-based nanoflowers utilizing high gravity technology. Owing to the significant intensification of micro-mixing and mass transfer in unique high gravity shearing surroundings, five typical binary/ternary Pt-based nanoflowers are instantaneously achieved at room temperature. As a proof-of-concept, as-synthesized Platinum-Silver nanoflowers (PtAg NFs) demonstrate excellent catalytic performance and anti-CO poisoning ability for anodic methanol oxidation reaction with high mass activity of 1830 mA mgPt -1, 3.5 and 3.2 times higher than those of conventional beaker products and commercial Pt/C, respectively. The experiment in combination with theory calculations suggest that the enhanced performance is due to additional electronic transmission and optimized d-band center of Pt caused by high alloying degree.

Reduced thermal conductivity and enhanced TE performance in CrSb2via Fe-Bi co-substitution.

The efficiency of thermoelectric (TE) technology relies on the performance of TE materials. Substitution with heavy elements is an effective strategy in TE for enhancing phonon scattering without much affecting electrical transport properties. However, selecting suitable dopants to achieve a high TE figure-of-merit (ZT) poses a significant challenge. Thus, in this study, the efficacy of combined (Fe and Bi) co-substitution in CrSb2is investigated as a promising strategy to enhance ZT by lowering thermal conductivity. A series of co-substituted Cr1-xFexBiySb2-y(x= 0, 0.25, 0.50, 0.75, 1 andy= 0.10, 0.15, 0.20,0.25) samples were synthesized via furnace reaction followed by spark plasma sintering technique. Phase analysis and temperature dependence TE transport properties were systematically studied on synthesized samples. Furthermore, to analyze the impact of disorder induced by Bi/Fe substitution, electronic structure calculation was performed using the projector augmented-wave method. Notably, Cr0.75Fe0.25Bi0.15Sb1.85exhibited a low thermal conductivity of ∼2.5 W m-1K-1at 300 K, which reduced to half compared to that of pristine CrSb2(∼5 W m-1K-1). This reduction is attributed to the introduction of significant mass fluctuations and point defects along with the presence of Bi at grain boundaries by co-substitution. Consequently, a remarkable 90% enhancement inZT(∼0.021) at 350 K was achieved for Cr0.75Fe0.25Bi0.15Sb1.85compared to that of pristine CrSb2(ZT∼ 0.012). This study can provide valuable insights into the rational design of effective dopants in other TE materials also.

Design Principles for Fluorinated Interphase Evolution via Conversion-Type Alloying Processes for Anticorrosive Lithium Metal Anodes.

Over the past decade, lithium metal has been considered the most attractive anode material for high-energy-density batteries. However, its practical application has been hindered by its high reactivity with organic electrolytes and uncontrolled dendritic growth, resulting in poor Coulombic efficiency and cycle life. In this paper, we propose a design strategy for interface engineering using a conversion-type reaction of metal fluorides to evolve a LiF passivation layer and Li-M alloy. Particularly, we propose a LiF-modified Li-Mg-C electrode, which demonstrates stable long-term cycling for over 2000 h in common organic electrolytes with fluoroethylene carbonate (FEC) additives and over 700 h even without additives, suppressing unwanted side reactions and Li dendritic growth. With the help of phase diagrams, we found that solid-solution-based alloying not only facilitates the spontaneous evolution of a LiF layer and bulk alloy but also enables reversible Li plating/stripping inward to the bulk, compared with intermetallic compounds with finite Li solubility.

Recycling of Ti and Si from Ti-bearing blast furnace slag and diamond wire saw silicon waste by flux alloying technique.

Two industrial solid wastes, Ti-bearing blast furnace slag (TBFS) and diamond wire saw silicon waste (DWSSW), contain large amounts of Ti and Si, and their accumulation wastes resources and intensifies environmental pollution. In the present study, DWSSW was used as the silicon source to reduce titanium oxide in TBFS by electromagnetic induction smelting, and meanwhile Na3AlF6 was added as a flux to improve the recycling of the wastes. Ti and Si of the two wastes were simultaneously recovered in the form of alloy. The effects of different addition amount of Na3AlF6 flux in the mixture of DWSSW and TBFS on chemical composition, viscosity, basicity and structure of slag were investigated. The dissolution behavior of SiO2 in Na3AlF6 flux was theoretically deduced and experimentally verification. The optimized recovery rate of Ti and Si were obtained, and the research realizes the efficient recycling of DWSSW and TBFS simultaneously.

Why do Single-Atom Alloys Catalysts Outperform both Single-Atom Catalysts and Nanocatalysts on MXene?

Single-atom alloys (SAAs), combining the advantages of single-atom and nanoparticles (NPs), play an extremely significant role in the field of heterogeneous catalysis. Nevertheless, understanding the catalytic mechanism of SAAs in catalysis reactions remains a challenge compared with single atoms and NPs. Herein, ruthenium-nickel SAAs (RuNiSAAs ) synthesized by embedding atomically dispersed Ru in Ni NPs are anchored on two-dimensional Ti3 C2 Tx MXene. The RuNiSAA-3 -Ti3 C2 Tx catalysts exhibit unprecedented activity for hydrogen evolution from ammonia borane (AB, NH3 BH3 ) hydrolysis with a mass-specific activity (rmass ) value of 333 L min-1 gRu -1 . Theoretical calculations reveal that the anchoring of SAAs on Ti3 C2 Tx optimizes the dissociation of AB and H2 O as well as the binding ability of H* intermediates during AB hydrolysis due to the d-band structural modulation caused by the alloying effect and metal-supports interactions (MSI) compared with single atoms and NPs. This work provides useful design principles for developing and optimizing efficient hydrogen-related catalysts and demonstrates the advantages of SAAs over NPs and single atoms in energy catalysis.

Toward Ultrahigh Thermoelectric Performance of Cu2 SnS3 -Based Materials by Analog Alloying.

Cu2 SnS3 is a promising thermoelectric candidate for power generation at medium temperature due to its low-cost and environmental-benign features. However, the high electrical resistivity due to low hole concentration severely restricts its final thermoelectric performance. Here, analog alloying with CuInSe2 is first adopted to optimize the electrical resistivity by promoting the formation of Sn vacancies and the precipitation of In, and optimize lattice thermal conductivity through the formation of stacking faults and nanotwins. Such analog alloying enables a greatly enhanced power factor of 8.03 µW cm-1 K-2 and a largely reduced lattice thermal conductivity of 0.38 W m-1  K-1 for Cu2 SnS3 - 9 mol.% CuInSe2 . Eventually, a peak ZT as high as 1.14 at 773 K is achieved for Cu2 SnS3 - 9 mol.% CuInSe2 , which is one of the highest ZT among the researches on Cu2 SnS3 -based thermoelectric materials. The work implies analog alloying with CuInSe2 is a very effective route to unleash superior thermoelectric performance of Cu2 SnS3 .

Zinc-Bismuth Binary Alloy Enabling High-Performance Aqueous Zinc Ion Batteries.

Reconfiguration of zinc anodes efficiently mitigates dendrite formation and undesirable side reactions, thus favoring the long-term cycling performance of aqueous zinc ion batteries (AZIBs). This study synthesizes a Zn@Bi alloy anode (Zn@Bi) using the fusion method, and find that the anode surfaces synthesized using this method have an extremely high percentage of Zn(002) crystalline surfaces. Experimental results indicate that the addition of bismuth inhibits the hydrogen evolution reaction and corrosion of zinc anodes. The finite-element simulation results indicate that Zn@Bi can effectively achieve a uniform anodic electric field, thereby regulating the homogeneous depositions of zinc ions and reducing the production of Zn dendrite. Theoretical calculations reveal that the incorporation of Bi favors the anode structure stabilization and higher adsorption energy of Zn@Bi corresponds to better Zn deposition kinetics. The Zn@Bi//Zn@Bi symmetric cell demonstrates an extended cycle life of 1000 h. Furthermore, when pairing Zn@Bi with an α-MnO2 cathode to construct a Zn@Bi//MnO2 cell, a specific capacity of 119.3 mAh g-1 is maintained even after 1700 cycles at 1.2 A g-1 . This study sheds light on the development of dendrite-free anodes for advanced AZIBs.

Modulation of Vacancy Defects and Texture for High Performance n-Type Bi2 Te3 via High Energy Refinement.

The carrier concentration in n-type layered Bi2 Te3 -based thermoelectric (TE) material is significantly impacted by the donor-like effect, which would be further intensified by the nonbasal slip during grain refinement of crushing, milling, and deformation, inducing a big challenge to improve its TE performance and mechanical property simultaneously. In this work, high-energy refinement and hot-pressing are used to stabilize the carrier concentration due to the facilitated recovery of cation and anion vacancies. Based on this, combined with SbI3 doping and hot deformation, the optimized carrier concentration and high texture degree are simultaneously realized. As a result, a peak figure of merit (zT) of 1.14 at 323 K for Bi2 Te2.7 Se0.3  + 0.05 wt.% SbI3 sample with the high bending strength of 100 Mpa is obtained. Furthermore, a 31-couple thermoelectric cooling device consisted of n-type Bi2 Te2.7 Se0.3  + 0.05 wt.% SbI3 and commercial p-type Bi0.5 Sb1.5 Te3 legs is fabricated, which generates the large maximum temperature difference (ΔTmax ) of 85 K at a hot-side temperature of 343 K. Thus, the discovery of recovery effect in high energy refinement and hot-pressing has significant implications for improving TE performance and mechanical strength of n-type Bi2 Te3 , thereby promoting its applications in harsh conditions.

Selective Scatterings of Phonons and Electrons in Defective Half-Heusler Nb1- δ CoSb for the Figure of Merit zT > 1.

The recently developed defective 19-electron half-Heusler (HH) compounds, represented by Nb1- δ CoSb, possess massive intrinsic vacancies at the cation site and thus intrinsically low lattice thermal conductivity that is desirable for thermoelectric (TE) applications. Yet the TE performance of defective HHs with a maximum figure of merit (zT) <1.0 is still inferior to that of the conventional 18-electron ones. Here, a peak zT exceeding unity is obtained at 1123 K for both Nb0.7 Ta0.13 CoSb and Nb0.6 Ta0.23 CoSb, a benchmark value for defective 19-electron HHs. The improved zT results from the achievement of selective scatterings of phonons and electrons in defective Nb0.83 CoSb, using lanthanide contraction as a design factor to select alloying elements that can strongly impede the phonon propagation but weakly disturb the periodic potential. Despite the massive vacancies induced strong point defect scattering of phonons in Nb0.83 CoSb, Ta alloying is still found effective in suppressing lattice thermal conductivity while maintaining the carrier mobility almost unchanged. In comparison, V alloying significantly deteriorates the carrier transport and thus the TE performance. These results enlarge the category of high-performance HH TE materials beyond the conventional 18-electron ones and highlight the effectiveness of selective scatterings of phonons and electrons in developing TE materials even with massive vacancies.

Bismuth Telluride Nanoplates Hierarchically Confined by Graphene and N-Doped C as Conversion-Alloying Anode Materials for Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) have broad application prospects in the field of electric energy storage systems because of its abundant K reserves, and similar "rocking chair" operating principle as lithium-ion batteries (LIBs). Aiming to the large volume expansion and sluggish dynamic behavior of anode materials for storing large sized K-ion, bismuth telluride (Bi2 Te3 ) nanoplates hierarchically encapsulated by reduced graphene oxide (rGO), and nitrogen-doped carbon (NC) are constructed as anodes for PIBs. The resultant Bi2 Te3 @rGO@NC architecture features robust chemical bond of Bi─O─C, tightly physicochemical confinement effect, typical conductor property, and enhanced K-ion adsorption ability, thereby producing superior electrochemical kinetics and outstanding morphological and structural stability. It is visually elucidated via high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) that conversion-alloying dual-mechanism plays a significant role in K-ion storage, allowing 12 K-ion transport per formular unit employing Bi as redox site. Thus, the high first reversible specific capacity of 322.70 mAh g-1 at 50 mA g-1 , great rate capability and cyclic stability can be achieved for Bi2 Te3 @rGO@NC. This work lays the foundation for an in-depth understanding of conversion-alloying mechanism in potassium-ion storage.

Coupling Single-Atom Sites and Ordered Intermetallic PtM Nanoparticles for Efficient Catalysis in Fuel Cells.

The design of an efficient catalytic system with low Pt loading and excellent stability for the acidic oxygen reduction reaction is still a challenge for the extensive application of proton-exchange membrane fuel cells. Here, a gas-phase ordered alloying strategy is proposed to construct an effective synergistic catalytic system that blends PtM intermetallic compounds (PtM IMC, M = Fe, Cu, and Ni) and dense isolated transition metal sites (M-N4 ) on nitrogen-doped carbon (NC). This strategy enables Pt nanoparticles and defects on the NC support to timely trap flowing metal salt without partial aggregation, which is attributed to the good diffusivity of gaseous transition metal salts with low boiling points. In particular, the resulting Pt1 Fe1 IMC cooperating with Fe-N4 sites achieves cooperative oxygen reduction with a half-wave potential up to 0.94 V and leads to a high mass activity of 0.51 A  mgPt -1 and only 23.5% decay after 30 k cycles, both of which exceed DOE 2025 targets. This strategy provides a method for reducing Pt loading in fuel cells by integrating Pt-based intermetallics and single transition metal sites to produce an efficient synergistic catalytic system.

Bimetallic CuSbSe2 : A Potential Anode Material for Sodium and Lithium-Ion Batteries with High-Rate Capability and Long-Term Stability.

Bimetallic transition metal chalcogenides (TMCs) materials have emerged as attractive anodes for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) because of the high intrinsic electronic conductivity, rich redox sites and unique reaction mechanism. In this work, we report the synthesis and electrochemical properties of a novel bimetallic TMCs material CuSbSe2 . The as-prepared anode delivers a high reversible capacity of 545.6  mA h g-1 for SIBs and 592.6  mA h g-1 for LIBs at a current density of 0.2 A g-1 , and an excellent rate capability of 425.9  mA h g-1 at 20 A g-1 for SIBs and 226.0  mA h g-1 at 10 A g-1 for LIBs without any common-used surface modification or carbonaceous compositing. In addition, ex situ X-ray diffraction (XRD) and High-resolution transmission electron microscopy (HRTEM) reveal a combined conversion-alloying reaction mechanism of LIBs and NIBs. Our findings suggest bimetallic CuSbSe2 could be a potential anode material for both SIBs and LIBs.

Promoting Photocatalytic Carbon Dioxide Reduction by Tuning the Properties of Cocatalysts.

Suppressing the amount of carbon dioxide in the atmosphere is an essential measure toward addressing global warming. Specifically, the photocatalytic CO2 reduction reaction (CRR) is an effective strategy because it affords the conversion of CO2 into useful carbon feedstocks by using sunlight and water. However, the practical application of photocatalyst-promoting CRR (CRR photocatalysts) requires significant improvement of their conversion efficiency. Accordingly, extensive research is being conducted toward improving semiconductor photocatalysts, as well as cocatalysts that are loaded as active sites on the photocatalysts. In this review, we summarize recent research and development trends in the improvement of cocatalysts, which have a significant impact on the catalytic activity and selectivity of photocatalytic CRR. We expect that the advanced knowledge provided on the improvement of cocatalysts for CRR in this review will serve as a general guideline to accelerate the development of highly efficient CRR photocatalysts.

Microstructure, Phase Evolution, and Chemical Behavior of CrCuFeNiTiAlx High Entropy Alloys Processed by Mechanical Alloying.

High entropy alloys (HEAs) of the type CrCuFeNiTi-Alx were processed through mechanical alloying. The aluminum concentration was varied in the alloy, to determine its effect on the HEAs' microstructure, phase formation, and chemical behavior. X-ray diffraction studies performed on the pressureless sintered samples revealed the presence of structures composed of face centered cubic (FCC) and body centered cubic (BCC) solid-solution phases. Since the valences of the elements that form the alloy are different, a nearly stoichiometric compound was obtained, increasing the final entropy of the alloy. The aluminum was partly responsible for this situation, which also favored transforming part of the FCC phase into BCC phase on the sintered bodies. X-ray diffraction also indicated the formation of different compounds with the alloy's metals. Bulk samples exhibited microstructures with different phases. The presence of these phases and the results of the chemical analyses revealed the formation of alloying elements that, in turn, formed a solid solution and, consequently, had a high entropy. From the corrosion tests, it could be concluded that the samples with a lower aluminum content were the most resistant to corrosion.

[Research status and development of biodegradable zinc alloy as orthopedics implant].

Znic (Zn) alloys with good cytocompatibility and suitable degradation rate have been a kind of biodegradable metal with great potential for clinical applications. This paper summarizes the biological role of degradable Zn alloy as bone implant materials, discusses the mechanical properties of different Zn alloys and their advantages and disadvantages as bone implant materials, and analyzes the influence of different processing strategies (such as alloying and additive manufacturing) on the mechanical properties of Zn alloys. This paper provides systematic design approaches for biodegradable Zn alloys as bone implant materials in terms of the material selection, product processing, structural topology optimization, and assesses their application prospects with a view to better serve the clinic.

Significant Strain Dissipation via Stiff-Tough Solid Electrolyte Interphase Design for Highly Stable Alloying Anodes.

The pulverization of alloying anodes significantly restricts their use in lithium-ion batteries (LIBs). This study presents a dual-phase solid electrolyte interphase (SEI) design that incorporates finely dispersed Al nanoparticles within the LiPON matrix. This distinctive dual-phase structure imparts high stiffness and toughness to the integrated SEI film. In comparison to single-phase LiPON film, the optimized Al/LiPON dual-phase SEI film demonstrates a remarkable increase in fracture toughness by 317.8 %, while maintaining stiffness, achieved through the substantial dissipation of strain energy. Application of the dual-phase SEI film on an Al anode leads to a 450 % enhancement in cycling stability for lithium storage in dual-ion batteries. A similar enhancement in cycling stability for silicon anodes, which face severe volume expansion issues, is also observed, demonstrating the broad applicability of the dual-phase SEI design. Specifically, homogeneous Li-Al alloying has been observed in conventional LIBs, even when paired with a high mass loading LiNi0.5 Co0.3 Mn0.2 O2 cathode (7 mg cm-2 ). The dual-phase SEI film design can also accelerate the diffusion kinetics of Li-ions through interface electronic structure regulation. This dual-phase design can integrate stiffness and toughness into a single SEI film, providing a pathway to enhance both the structural stability and rate capability of alloying anodes.