Ternary Eutectic Electrolyte-Assisted Formation and Dynamic Breathing Effect of the Solid-Electrolyte Interphase for High-Stability Aqueous Magnesium-Ion Full Batteries

Aqueous rechargeable magnesium batteries hold immense potential for intrinsically safe, cost-effective, and sustainable energy storage. However, their viability is constrained by a narrow voltage range and suboptimal compatibility between the electrolyte and electrodes. Herein, we introduce an innovative ternary deep eutectic Mg-ion electrolyte composed of MgCl2·6H2O, acetamide, and urea in a precisely balanced 1:1:7 molar ratio. This formulation was optimized by leveraging competitive solvation effects between Mg2+ ions and two organic components. The full batteries based on this ternary eutectic electrolyte, Mn-doped sodium vanadate (Mn-NVO) anode, and copper hexacyanoferrate cathode exhibited an elevated voltage plateau and high rate capability and showcased stable cycling performance. Ex-situ characterizations unveiled the Mg2+ storage mechanism of Mn-NVO involving initial extraction of Na+ followed by subsequent Mg2+ intercalation/deintercalation. Detailed spectroscopic analyses illuminated the formation of a pivotal solid-electrolyte interphase on the anode surface. Moreover, the solid-electrolyte interphase demonstrated a dynamic adsorption/desorption behavior, referred to as the "breathing effect", which substantially mitigated undesired dissolution and side reactions of electrode materials. These findings underscore the crucial role of rational electrolyte design in fostering the development of a favorable solid-electrolyte interphase that can significantly enhance compatibility between electrode materials and electrolytes, thus propelling advancements in aqueous multivalent-ion batteries.

Precipitated Iodine Cathode Enabled by Trifluoromethanesulfonate Oxidation for Cathode/Electrolyte Mutualistic Aqueous Zn-I Batteries

Aqueous Zn-I batteries hold great potential for high-safety and sustainable energy storage. However, the iodide shuttling effect and the hydrogen evolution reaction that occur in the aqueous electrolyte remain the main obstacles for their further development. Herein, the design of a cathode/electrolyte mutualistic aqueous (CEMA) Zn-I battery based on the inherent oxidation ability of aqueous trifluoromethanesulfonate ((OTf)- ) electrolyte toward triiodide species is presented. This results in the formation of iodine sediment particles assembled by fine iodine nanocrystals (≈10 nm). An iodine host cathode with high areal iodine loading is realized via a spontaneous absorption process that enriched redox-active iodine and iodide species from aqueous electrolyte onto nanoporous carbon based current collector. By tuning iodide redox process and suppressing competitive hydrogen evolution reaction, the assembled CEMA Zn-I batteries demonstrate a remarkable capacity retention of 76.9% over 1000 cycles at 0.5 mA cm-2 . Moreover, they exhibit a notable rate capability, with a capacity retention of 74.6% when the current density is increased from 0.5 to 5.0 mA cm-2 . This study demonstrates the feasibility of using the oxidation effect to repel redox-active species from the electrolyte to the cathode, paving a new avenue for high-performance aqueous Zn-I batteries.

Sandwiched Epitaxy Growth of 2D Single-Crystalline Hexagonal Bismuthene Nanoflakes for Electrocatalytic CO2 Reduction

Two-dimensional (2D) bismuthene is predicted to possess intriguing physical properties, but its preparation remains challenging due to the high surface energy constraint. Herein, we report a sandwiched epitaxy growth strategy for the controllable preparation of 2D bismuthene between a Cu foil substrate and a h-BN covering layer. The top h-BN layer plays a crucial role in suppressing the structural transformation of bismuthene and compensating for the charge transfer from the bismuthene to the Cu(111) surface. The bismuthene nanoflakes present a superior thermal stability up to 500 °C in air, attributed to the passivation effect of the h-BN layer. Moreover, the bismuthene nanoflakes demonstrate an ultrahigh faradaic efficiency of 96.3% for formate production in the electrochemical CO2 reduction reaction, which is among the highest reported for Bi-based electrocatalysts. This study offers a promising approach to simultaneously synthesize and protect 2D bismuthene nanoflakes, which can be extended to other 2D materials with a high surface energy.

Ultrafast Thermal Shock Synthesis and Porosity Engineering of 3D Hierarchical Cu-Bi Nanofoam Electrodes for Highly Selective Electrochemical CO2 Reduction

Massive production of practical metal or alloy based electrocatalysts for electrocatalytic CO2 reduction reaction is usually limited by energy-extensive consumption, poor reproducibility, and weak adhesion on electrode substrates. Herein, we report the ultrafast thermal shock synthesis and porosity engineering of free-standing Cu-Bi bimetallic nanofoam electrocatalysts with 3D hierarchical porous structure and easily adjustable compositions. During the thermal shock process, the rapid heating and cooling steps in several seconds result in strong interaction between metal nanopowders to form multiphase nanocrystallines with abundant grain boundaries and metastable CuBi intermetallic phase. The subsequent porosity engineering process via acid etching and electroreduction creates highly porous Cu-Bi structures that can increase electrochemically active surface area and facilitate mass/charge transfer. Among the Cu-Bi nanofoam electrodes with different Cu/Bi ratios, the Cu4Bi nanofoam exhibited the highest formate selectivity with a Faradaic efficiency of 92.4% at -0.9 V (vs reversible hydrogen electrode) and demonstrated excellent operation stability.

An engineered nanoplatform inhibiting energy metabolism and lysosomal activity of tumor cells to multiply cisplatin-based chemotherapy

Although inhibiting the energy metabolism of tumor cells has become an effective measure to enhance chemotherapy, tumor cells can still escape the lethal effect of chemotherapy by entering a dormancy state with low-energy expenditure. Herein, the glutathione (GSH)-responsive nanoplatform (C-A-D NPs) were constructed to inhibit energy metabolism and lysosomal activity of tumor cells, thereby forcing tumor cells to remain vulnerable to cisplatin. In this system, cisplatin prodrug was reduced to cisplatin by GSH, and D-peptide and apoptozole (Az) were released to inhibit the energy metabolism and autophagy-lysosome pathway of tumor cells. The suppressed autophagy-lysosome pathway prevents tumor cells from entering a low-energy dormancy state, resulting in the loss of resistance to the lethal effect of cisplatin with high-energy expenditure and insufficient energy supply. Such engineered nanoplatform effectively enhances the chemotherapeutic effect of cisplatin by inhibiting intracellular energy metabolism and lysosomal activity, showing great clinical prospects.

Fluorinated Interface Engineering toward Controllable Zinc Deposition and Rapid Cation Migration of Aqueous Zn-Ion Batteries

Metallic zinc (Zn) is a highly promising anode material for aqueous energy storage systems due to its low redox potential, high theoretical capacity, and low cost. However, rampant dendrites/by-products and torpid Zn2+ transfer kinetics at electrode/electrolyte interface severely threaten the cycling stability, which deteriorate the electrochemical performance of Zn-ion batteries. Herein, an interfacial engineering strategy to construct alkaline earth fluoride modified metal Zn electrodes with long lifespan and high capacity retention is reported. The compact fluoride layer is revealed to guide uniform Zn stripping/plating and accelerate the transfer/diffusion of Zn2+ via Maxwell-Wagner polarization. A series of in situ and ex situ spectroscopic studies verified that the fluoride layer can guide uniform Zn stripping/plating. Electrochemical kinetics analyses reveal that positive effect on the removal of Zn2+ solvation sheath provided by fluoride layer. Meanwhile, this fluoride coating layer can act as a barrier between the Zn electrode and electrolyte, providing a high electrode overpotential toward hydrogen evolution reaction to hold back H2 evolution. Consequently, the fluoride-modified Zn anode exhibited a capacity retention of 88.2% after 4000 cycles under10 A g-1 . This work opens up a new path to interface engineering for propelling the exploration of advanced rechargeable aqueous Zn-ion batteries.

Tunable C2 Products via Photothermal Steam Reforming of CO2 over Surface-Modulated Mesoporous Cobalt Oxides

The conversion of CO₂ to high-value products by renewable energy is a promising approach for realizing carbon neutralization, but the selectivity and efficiency of C₂₊ products are not satisfying. Herein, we report the controllable preparation of highly ordered mesoporous cobalt oxides with modulated surface states to achieve efficient photothermal water-steam reforming of CO₂ to C₂ products with high activity and tunable selectivity. Pristine mesoporous Co₃O₄ exhibited an acetic acid selectivity of 96% with a yield rate of 73.44 μmol g^-1 h^-1. By rationally modifying mesoporous Co₃O₄ surface states, mesoporous Co₃O₄@CoO delivered a radically altered ∼100% ethanol selectivity with a yield rate of 14.85 μmol g^-1 h^-1. Comprehensive experiments revealed that the pH value could strongly influence the selectivity of C₂ products over mesoporous cobalt oxides. Density functional theory verified that reduced surface states and rich oxygen vacancies on surface-modified mesoporous cobalt oxides could facilitate further variation of C₂ products from acetic acid to ethanol.

Rapid and Green Electric-Explosion Preparation of Spherical Indium Nanocrystals with Abundant Metal Defects for Highly-Selective CO2 Electroreduction

Electrochemical conversion of CO₂ into high-value-added chemicals has been considered a promising route to achieve carbon neutrality and mitigate the global greenhouse effect. However, the lack of highly efficient electrocatalysts has limited its practical application. Herein, we propose an ultrafast and green electric explosion method to batch-scale prepare spherical indium (In) nanocrystals (NCs) with abundant metal defects toward high selective electrocatalytic CO₂ reduction (CO₂RR) to HCOOH. During the electric explosion synthesis process, the Ar atmosphere plays a significant role in forming the spherical In NCs with abundant metal defects instead of highly crystalline In₂O₃ NCs formed under an air atmosphere. Analysis results reveal that the In NCs possess ultrafast catalytic kinetics and reduced onset potential, which is ascribed to the formation of rich metal defects serving as effective catalytic sites for converting CO₂ into HCOOH. This work provides a feasible strategy to massively produce efficient In-based electrocatalysts for electrocatalytic CO₂-to-formate conversion.

Cooperative Cationic and Anionic Redox Reactions in Ultrathin Polyvalent Metal Selenide Nanoribbons for High-Performance Electrochemical Magnesium-Ion Storage

Rechargeable magnesium batteries (RMBs) are considered as potential energy storage devices due to their high volumetric specific capacity, good safety, as well as source abundance. Despite extensive efforts devoted to constructing an efficient magnesium battery system, the sluggish Mg²⁺ diffusion in conventional cathode materials often leads to slow rate kinetics, low capacity, and poor cycling lifespan. Although transition metal selenides with soft anion frameworks have attracted extensive attention, their Mg²⁺ storage mechanism still needs to be clarified. Herein, we demonstrate that the ultrathin CoSe₂ nanoribbons can be used as a robust cathode material for RMBs and reveal a novel Mg²⁺ storage mechanism based on cooperative cationic (Co) and anionic (Se) redox processes via systematic ex-situ characterizations. Compared to other metal selenide cathodes based on conversion reactions of solely metal cations, the cooperative cationic-anionic redox reactions of the CoSe₂ cathode contribute to obtaining an enhanced specific capacity and boosted electrochemical kinetics. Moreover, on one hand, the ultrathin nanoribbon structure enables effective contact between the electrode material and electrolyte and on the other hand significantly reduces the length and time consumption of Mg²⁺ diffusion, leading to dominated surface-driven capacitance-controlled Mg²⁺ storage behavior and rapid Mg²⁺ storage kinetics. As a result, the ultrathin CoSe₂ nanoribbon cathode exhibits a reversible discharge capacity of ∼130 mAh g^-1 at 100 mA g^-1, good rate capability (116 mAh g^-1 at 300 mA g^-1), and long cyclability over 600 cycles. This finding confirms the development potentiality of polyvalent metal selenide cathode materials based on a cooperative cationic-anionic redox mechanism for the construction of next-generation multivalent secondary batteries.

Batch-Scale Synthesis of Nanoparticle-Agminated Three-Dimensional Porous Cu@Cu2O Microspheres for Highly Selective Electrocatalysis of Nitrate to Ammonia

The electrochemical nitrate reduction reaction (NITRR), which converts nitrate to ammonia, is promising for artificial ammonia synthesis at mild conditions. However, the lack of favorable electrocatalysts has hampered its large-scale applications. Herein, we report the batch-scale synthesis of three-dimensional (3D) porous Cu@Cu₂O microspheres (Cu@Cu₂O MSs) composed of fine Cu@Cu₂O nanoparticles (NPs) using a convenient electric explosion method with outstanding activity and stability for the electrochemical reduction of nitrate to ammonia. Density functional theory (DFT) calculations revealed that the Cu₂O (111) facets could facilitate the formation of *NO₃H and *NO₂H intermediates and suppress the hydrogen evolution reaction (HER), resulting in high selectivity for the NITRR. Moreover, the 3D porous structure of Cu@Cu₂O MSs facilitates electrolyte penetration and increases the localized concentration of reactive species for the NITRR. As expected, the obtained Cu@Cu₂O MSs exhibited an ultrahigh NH₃ production rate of 327.6 mmol·h^-1·g^-1_cat. (which is superior to that of the Haber-Bosch process with a typical NH₃ yield <200 mmol h^-1g^-1_cat.), a maximum Faradaic efficiency of 80.57%, and remarkable stability for the NITRR under ambient conditions. Quantitative ¹⁵N isotope labeling experiments indicated that the synthesized ammonia originated from the electrochemical reduction of nitrate. Achieving the batch-scale and low-cost production of high-performance Cu@Cu₂O MSs electrocatalysts using the electric explosion method is promising for the large-scale realization of selective electrochemical reduction of nitrate toward artificial ammonia synthesis.

Single-Atom Metal Anchored Zr6-Cluster-Porphyrin Framework Hollow Nanocapsules with Ultrahigh Active-Center Density for Electrocatalytic CO2 Reduction

Designing earth-abundant electrocatalysts toward highly efficient CO₂ reduction has significant importance to decrease the global emission of greenhouse gas. Herein, we propose an efficient strategy to anchor non-noble metal single atoms on Zr₆-cluster-porphyrin framework hollow nanocapsules with well-defined and abundant metal-N₄ porphyrin sites for efficient electrochemical CO₂ reduction. Among different transition metal single atoms (Mn, Fe, Co, Ni, and Cu), Co single-atom anchored Zr₆-cluster-porphyrin framework hollow nanocapsules demonstrated the highest activity and selectivity for CO production. The rich Co-N₄ active centers and hierarchical porous structure contribute to enhanced CO₂ adsorption capability and moderate binding strength of reaction intermediates, thus facilitating *CO desorption and CO₂-to-CO conversion. The Co-anchored nanocapsules maintain high efficiency and well-preserved stability during long-term electrocatalysis tests. Moreover, the Co-anchored nanocapsules exhibit a remarkable solar-to-CO energy conversion efficiency of 12.5% in an integrated solar-driven CO₂ reduction/O₂ evolution electrolysis system when powered by a custom large-area [Cs_0.05(FA_0.85MA_0.15)_0.95]Pb_0.9(I_0.85Br_0.15)₃-based perovskite solar cell.

Crystalline Modulation Engineering of Ru Nanoclusters for Boosting Ammonia Electrosynthesis from Dinitrogen or Nitrate

Developing highly efficient nitrogen reduction reaction (NRR) and nitrate reduction reaction (NITRR) electrocatalysts is an ongoing challenge. Herein, we report the in situ growth of ultrafine amorphous Ru nanoclusters with a uniform diameter of ∼1.2 nm on carbon nanotubes as a highly efficient electrocatalyst for both the NRR and the NITRR. The amorphous Ru nanoclusters were prepared via a convenient ambient chelated co-reduction method, in which trisodium citrate as a chelating agent played a key role to form amorphous Ru instead of crystalline Ru. The strong d-π interaction between Ru metal and carbon nanotubes led to the homogeneous distribution and good long-term stability of ultrafine Ru nanoclusters. Compared with crystalline Ru, amorphous Ru nanoclusters with abundant low-coordinate atoms can provide more catalytic sites. The amorphous Ru nanoclusters exhibited an NH₃ yield of 10.49 μg·h^-1·mg_cat.^-1 and a FE_NH3 of 17.48% at -0.2 V vs reversible hydrogen electrode (RHE) for NRR. For the NITRR, an NH₃ yield of 145.1 μg·h^-1·mg_cat.^-1 and a FE_NH3 of 80.62% were also achieved at -0.2 V vs RHE. This work provides new insights into crystalline modulation engineering of metal nanoclusters for electrocatalytic ammonia synthesis.

Interfacial Reduction Nucleation of Noble Metal Nanodots on Redox-Active Metal-Organic Frameworks for High-Efficiency Electrocatalytic Conversion of Nitrate to Ammonia

Electrochemically converting nitrate to ammonia is a promising route to realize artificial nitrogen recycling. However, developing highly efficient electrocatalysts is an ongoing challenge. Herein, we report the construction of stable and redox-active zirconium metal-organic frameworks (Zr-MOFs) based on Zr₆ nanoclusters and redox-reversible tetrathiafulvalene (TTF) derivatives as inorganic nodes and organic linkers, respectively. The redox-active Zr-MOF can facilitate the in situ reduction of noble metal precursors free of external reductants and realize the uniform nucleation of noble metal nanodots (NDs) on Zr-MOF, achieving the preparation of M-NDs/Zr-MOF (M = Pd, Ag, or Au). The highly porous Zr-MOF with good conductivity can facilitate the mass transfer process. Among the M-NDs/Zr-MOF catalysts, Pd-NDs/Zr-MOF exhibits the highest electrocatalytic activity, delivering a NH₃ yield of 287.31 mmol·h^-1·g^-1_cat. and a Faradaic efficiency of 58.1%. The proposed interfacial reduction nucleation strategy for anchoring M NDs on Zr-MOFs can be applied to other challenging energy conversion reactions.

2D Arsenene and Arsenic Materials: Fundamental Properties, Preparation, and Applications

As emerging 2D materials, arsenene and arsenic materials have attracted rising interest in the past few years. The diverse crystalline phases, exotic electrical characteristics, and widespread applications of 2D arsenene and arsenic bring them great research value and utilization potential. Herein, the recent progress of 2D arsenene and arsenic is reviewed in terms of fundamental properties, preparation, and applications. The fundamental properties of 2D arsenene and arsenic, including the crystal phases, environmental stability, and electrical structure, from theoretical to experimental reports are first summarized. Then, the experimental processes for preparing 2D arsenene and arsenic, along with their respective advantages and disadvantages, are introduced including epitaxial growth, mechanical exfoliation, and liquid-phase exfoliation. Moreover, applications of 2D arsenene and arsenic are discussed, suggesting a wide range of applications of 2D arsenene and arsenic in field-effect transistors, sensors, catalysts, biological applications, and so on. Finally, some perspectives about the challenges and opportunities of promising 2D arsenene and arsenic are provided. This review provides a helpful guidance and stimulates more focus on future explorations and developments of 2D arsenene and arsenic.

A Review on Recent Advances for Boosting Initial Coulombic Efficiency of Silicon Anodic Lithium Ion batteries

Rechargeable silicon anode lithium ion batteries (SLIBs) have attracted tremendous attention because of their merits, including a high theoretical capacity, low working potential, and abundant natural sources. The past decade has witnessed significant developments in terms of extending the lifespan and maintaining high capacities of SLIBs. However, the detrimental issue of low initial Coulombic efficiency (ICE) toward SLIBs is causing more and more attention in recent years because ICE value is a core index in full battery design that profoundly determines the utilization of active materials and the weight of an assembled battery. Herein, a comprehensive review is presented of recent advances in solutions for improving ICE of SLIBs. From design perspectives, the strategies for boosting ICE of silicon anodes are systematically categorized into several aspects covering structure regulation, prelithiation, interfacial design, binder design, and electrolyte additives. The merits and challenges of various approaches are highlighted and discussed in detail, which provides valuable insights into the rational design and development of state-of-the-art techniques to deal with the deteriorative issue of low ICE of SLIBs. Furthermore, conclusions and future promising research prospects for lifting ICE of SLIBs are proposed at the end of the review.

Quasi-Phthalocyanine Conjugated Covalent Organic Frameworks with Nitrogen-Coordinated Transition Metal Centers for High-Efficiency Electrocatalytic Ammonia Synthesis

Developing high-performance nitrogen reduction reaction (NRR) electrocatalysts is an ongoing challenge. Herein, we report a pyrolysis-free synthetic method for introducing ordered quasi-phthalocyanine N-coordinated transition metal (Ti, Cu, or Co) centers into a conjugated two-dimensional (2D) covalent organic framework (COF) for enhanced NRR performance. Detailed experiments and characterizations revealed that the NRR activity of Ti-COF was clearly better than that of Cu-COF and Co-COF, because of the superior abilities of Ti metal centers in activating inert N₂ molecules and suppressing the hydrogen evolution reaction (HER). The resulting Ti-COF exhibits a high NH₃ yield of 26.89 μg h^-1 mg^-1_cat. and a Faradaic efficiency of 34.62% for NRR. Density functional theory (DFT) calculations verify that Ti-COF can effectively adsorb and activate N₂ molecules and inhibit HER compared with Cu-COF, Co-COF, and pristine COF catalysts. This work opens a new avenue for developing 2D-COF materials that contain abundant coordinated transition metal centers toward electrocatalytic NRR.

Rh/Al Nanoantenna Photothermal Catalyst for Wide-Spectrum Solar-Driven CO2 Methanation with Nearly 100% Selectivity

Solar-powered CO₂ conversion represents a promising green and sustainable approach for achieving a carbon-neutral economy. However, the rational design of a wide-spectrum sunlight-driven catalysis system for effective CO₂ reduction is an ongoing challenge. Herein, we report the preparation of a rhodium/aluminum (Rh/Al) nanoantenna photothermal catalyst that can utilize a broad range of sunlight (from ultraviolet to the near-infrared region) for highly efficient CO₂ methanation, achieving a high CH₄ selectivity of nearly 100% and an unprecedented CH₄ productivity of 550 mmol·g^-1·h^-1 under concentrated simulated solar irradiation (11.3 W·cm^-2). Detailed control experiment results verified that the CO₂ methanation process was facilitated by the localized surface plasmonic resonance and nanoantenna effects of the Rh/Al nanostructure under light irradiation. In operando temperature-programmed Fourier transform infrared spectroscopy confirmed that CO₂ methanation on the Rh/Al nanoantenna catalyst was a multistep reaction with CO as a key intermediate. The design of a wide-spectrum solar-driven photothermal catalyst provides a feasible strategy for boosting CO₂-to-fuel conversion.

Controlled growth and ion intercalation mechanism of monocrystalline niobium pentoxide nanotubes for advanced rechargeable aluminum-ion batteries

Rechargeable aluminum-ion batteries (RAIBs) have attracted increasing attention owing to their high theoretical volumetric capacity, high resource abundance, and good safety performance. However, the existing RAIB systems usually exhibit relatively low specific capacities limited by the cathode materials. In this study, we developed a one-step chemical vapor deposition method to prepare single-crystal orthogonal Nb2O5 nanotubes for serving as high-performance electrode materials for RAIBs, showing a high reversible capability of 556 mA h g-1 at 25 mA g-1 and good thermal endurability at elevated temperatures (50 °C). A combination of a series of detailed ex situ structural characterization studies verified the reversible intercalation/deintercalation of chloroaluminate anions (AlCl4-) into/from the (001) planes of monocrystalline Nb2O5 nanotubes. It also revealed that the nanoarchitecture of Nb2O5 nanotubes with thin tube walls, hollow inner space and a short ion transport distance is conducive to the rapid kinetics of the insertion/extraction process. This work provides a promising route to design high-performance electrode materials based on transition metal compounds for RAIBs via the rational modulation of their structure and morphology.

Porous gold layer coated silver nanoplates with efficient antimicrobial activity

Although silver nanoparticles are considered as promising antibacterial agents because of their antibacterial activity, the acute cytotoxicity of Ag⁺ released from Ag nanoparticles restricts their potential practical applications. Herein, porous Ag@Au nanoplates, which could balance the Ag⁺ release and the toxicity of Ag naoparticles, were fabricated by stepwise seed-mediated growth and oxidation. Laser irradiation further boosted their antimicrobial activity, and significantly accelerated the curing rate of wound. Comparing with Ag nanoplates, the irradiated porous Ag@Au nanoplates showed the similar antibiotic ability against S. aureus strains and lower cytotoxicity in vitro. When the porous Ag@Au nanoplates were applied to treat S. aureus-infected wound, they had the best curing effect. Thus, these porous Ag@Au nanoplates could act as promising antibacterial agents for wound healing applications.

Surface plasmon resonance enhanced direct Z-scheme TiO2/ZnTe/Au nanocorncob heterojunctions for efficient photocatalytic overall water splitting

Solar-driven photocatalytic overall water splitting is regarded as one of the ideal strategies to generate renewable hydrogen energy without the initiation of environmental issues. However, there are still a few remaining challenges to develop wide-light-absorption and stable photocatalysts for the simultaneous production of H2 and O2 in pure water without sacrificial reagents. Herein, we report the design and preparation of Z-scheme TiO2/ZnTe/Au nanocorncob heterojunctions by homogeneously decorating Au nanoparticles onto the surface of core-shell TiO2/ZnTe coaxial nanorods for highly efficient overall water splitting. With the appropriate band structure of TiO2/ZnTe heterojunctions and the surface plasmon resonance enhancement of Au nanoparticles, the well-designed TiO2/ZnTe/Au nanocorncob heterojunctions can synergistically make effective utilization of broad-range solar light illunimation and enhance the separation efficency of electron-hole pairs, as evidenced by UV-Vis absorption and time-resolved photoluminescence spectroscopy. Photoelectrochemical characterization confirms that the water-splitting reaction on TiO2/ZnTe/Au nanocorncobs is mainly carried out via a two-electron/two-electron transfer process with an intermediate product of H2O2. As a result, the TiO2/ZnTe/Au nanocorncob photocatalyst can generate H2 and O2 with a stoichiometric ratio of 2 : 1 under light irradiation without any sacrificial agents, exhibiting a high H2 production rate of 3344.0 μmol g-1 h-1 and a solar-to-hydrogen (STH) efficiency of 0.98%. Moreover, the TiO2/ZnTe/Au nanocorncob heterojunctions show high stability and well-preserved morphological integrity after long-term photocatalytic tests. This study provides a prototype route to produce clean hydrogen energy from only sunlight, pure water, and rationally-designed heterojunction photocatalysts.

Nitrogen-Doped Carbon Nanotube Forests Planted on Cobalt Nanoflowers as Polysulfide Mediator for Ultralow Self-Discharge and High Areal-Capacity Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries with high theoretical energy density have caught enormous attention for electrochemical power source applications. However, the development of Li-S batteries is hindered by the electrochemical performance decay that resulted from low electrical conductivity of sulfur and serious shuttling effect of intermediate polysulfides. Moreover, the areal capacity is usually restricted by the low areal sulfur loadings (1.0-3.0 mg cm^-2). When the areal sulfur loading increases to a practically accepted level above 3.0-5.0 mg cm^-2, the areal capacity and cycling life tend to become inferior. Herein, we report an effective polysulfide mediator composed of nitrogen-doped carbon nanotube (N-CNT) forest planted on cobalt nanoflowers (N-CNTs/Co-NFs). The abundant pores in N-CNTs/Co-NFs can allow a high sulfur content (78 wt %) and block the dissolution/diffusion of polysulfides via physical confinement, and the Co nanoparticles and nitrogen heteroatoms (4.3 at. %) can enhance the polysulfide retention via strong chemisorption capability. Moreover, the planted N-CNT forest on N-CNTs/Co-NFs can enable fast electron transfer and electrolyte penetration. Benefiting from the above merits, the sulfur-filled N-CNTs/Co-NFs (S/N-CNTs/Co-NFs) cathodes with high areal sulfur loadings exhibit low self-discharge rate, high areal capacity, and stable cycling performance.

Highly Branched VS4 Nanodendrites with 1D Atomic-Chain Structure as a Promising Cathode Material for Long-Cycling Magnesium Batteries

Rechargeable magnesium batteries have attracted increasing attention due to the high theoretical volumetric capacities, dendrite formation-free characteristic and low cost of Mg metal anodes. However, the development of magnesium batteries is seriously hindered by the lack of capable cathode materials with long cycling life and fast solid-state diffusion kinetics for highly-polarized divalent Mg²⁺ ions. Herein, vanadium tetrasulfide (VS₄ ) with special one-dimensional atomic-chain structure is reported to be able to serve as a favorable cathode material for high-performance magnesium batteries. Through a surfactant-assisted solution-phase process, sea-urchin-like VS₄ nanodendrites are controllably prepared. Benefiting from the chain-like crystalline structure of VS₄ , the S₂^2- dimers in the VS₄ nanodendrites provide abundant sites for Mg²⁺ insertion. Moreover, the VS₄ atomic-chains bonded by weak van der Waals forces are beneficial to the diffusion kinetics of Mg²⁺ ions inside the open channels of VS₄ . Through a series of systematic ex situ characterizations and density functional theory calculations, the magnesiation/demagnesiation mechanism of VS₄ are elucidated. The VS₄ nanodendrites present remarkable performance for Mg²⁺ storage among existing cathode materials, exhibiting a remarkable initial discharge capacity of 251 mAh g^-1 at 100 mA g^-1 and an impressive long-term cyclability at large current density of 500 mA g^-1 (74 mAh g^-1 after 800 cycles).

Strong Capillarity, Chemisorption, and Electrocatalytic Capability of Crisscrossed Nanostraws Enabled Flexible, High-Rate, and Long-Cycling Lithium-Sulfur Batteries

The development of flexible lithium-sulfur (Li-S) batteries with high energy density and long cycling life are very appealing for the emerging flexible, portable, and wearable electronics. However, the progress on flexible Li-S batteries was limited by the poor flexibility and serious performance decay of existing sulfur composite cathodes. Herein, we report a freestanding and highly flexible sulfur host that can simultaneously meet the flexibility, stability, and capacity requirements of flexible Li-S batteries. The host consists of a crisscrossed network of carbon nanotubes reinforced CoS nanostraws (CNTs/CoS-NSs). The CNTs/CoS-NSs with large inner space and high conductivity enable high loading and efficient utilization of sulfur. The strong capillarity effect and chemisorption of CNTs/CoS-NSs to sulfur species were verified, which can efficiently suppress the shuttle effect and promote the redox kinetics of polysulfides. The sulfur-encapsulated CNTs/CoS-NSs (S@CNTs/CoS-NSs) cathode in Li-S batteries exhibits superior performance, including high discharge capacity, rate capability (1045 mAh g^-1 at 0.5 C and 573 mAh g^-1 at 5.0 C), and cycling stability. Intriguingly, the soft-packed Li-S batteries based on S@CNTs/CoS-NSs cathode show good flexibility and stability upon bending.

Interface Engineering of Anchored Ultrathin TiO2/MoS2 Heterolayers for Highly-Efficient Electrochemical Hydrogen Production

An efficient self-standing hydrogen evolution electrode was prepared by in situ growth of stacked ultrathin TiO₂/MoS₂ heterolayers on carbon paper (CP@TiO₂@MoS₂). Owing to the high overall conductivity, large electrochemical surface area and abundant active sites, this novel electrode exhibits an excellent performance for hydrogen evolution reaction (HER). Remarkably, the composite electrode shows a low Tafel slope of 41.7 mV/dec, and an ultrahigh cathodic current density of 550 mA/cm² at a very low overpotential of 0.25 V. This work presents a new universal strategy for the construction of effective, durable, scalable, and inexpensive electrodes that can be extended to other electrocatalytic systems.

Solution synthesis and phase control of inorganic perovskites for high-performance optoelectronic devices

An efficient method to synthesize well-crystallized inorganic cesium lead halide perovskites (CsPbX₃, X = I or Br) with high yield and high reproducibility was proposed. Notably, the as-prepared CsPbI₃ in the yellow orthorhombic phase (y-CsPbI₃) can be easily converted to the black cubic perovskite phase CsPbI₃ (b-CsPbI₃) after thermal annealing. Furthermore, two-terminal photodetectors and all-inorganic perovskite solar cells based on b-CsPbI₃ were fabricated, exhibiting high performances.

High-Performance Li-Se Batteries Enabled by Selenium Storage in Bottom-Up Synthesized Nitrogen-Doped Carbon Scaffolds

Selenium (Se) has great promise to serve as cathode material for rechargeable batteries because of its good conductivity and high theoretical volumetric energy density comparable to sulfur. Herein, we report the preparation of mesoporous nitrogen-doped carbon scaffolds (NCSs) to restrain selenium for advanced lithium-selenium (Li-Se) batteries. The NCSs synthesized by a bottom-up solution-phase method have graphene-like laminar structure and well-distributed mesopores. The unique architecture of NCSs can severe as conductive framework for encapsulating selenium and polyselenides, and provide sufficient pathways to facilitate ion transport. Furthermore, the laminar and porous NCSs can effectively buffer the volume variation during charge/discharge processes. The integrated composite of Se-NCSs has a high Se content and can ensure the complete electrochemical reactions of Se and Li species. When used for Li-Se batteries, the cathodes based on Se-NCSs exhibit high capacity, remarkable cyclability, and excellent rate performance.

Bottom-up synthesis of nitrogen-doped porous carbon scaffolds for lithium and sodium storage

Here we report an effective bottom-up solution-phase process for the preparation of nitrogen-doped porous carbon scaffolds (NPCSs), which can be employed as high-performance anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The as-obtained NPCSs show favorable features for electrochemical energy storage such as high specific surface area, appropriate pore size distribution (3.9 nm in average), large pore volume (1.36 cm³ g^-1), nanosheet-like morphology, a certain degree of graphitization, enlarged interlayer distance (0.38 nm), high content of nitrogen (∼5.6 at%) and abundant electrochemically-active sites. Such a unique architecture provides efficient Li⁺/Na⁺ reservoirs, and also possesses smooth electron transport pathways and electrolyte access. For LIBs, the anodes based on NPCSs deliver a high reversible capacity of 1275 mA h g^-1 after 250 cycles at 0.5 C (1 C = 372 mA g^-1), and outstanding cycling stabilities with a capacity of 518 mA h g^-1 after 500 cycles at 5 C and 310 mA h g^-1 after 1500 cycles even at 10 C. For SIBs, the anodes based on NPCSs display a reversible capacity of 257 mA h g^-1 at 50 mA g^-1, and superior long-term cycling performance with a capacity of 191 mA h g^-1 after 1000 cycles at 200 mA g^-1.

Pine needle-derived microporous nitrogen-doped carbon frameworks exhibit high performances in electrocatalytic hydrogen evolution reaction and supercapacitors

The design of electrochemically active materials with appropriate structures and compositions is very important for applications in energy conversion and storage devices. Herein, we demonstrate an effective strategy to prepare microporous heteroatom-doped carbon frameworks derived from naturally-abundant pine needles. The preparation procedure is based on the carbonization of pine needles, followed by KOH activation at a temperature range of 700-1000 °C. The resultant nitrogen-doped carbon consists of abundant micropores and an ultrahigh specific surface area (up to 2433 m² g^-1), leading to high performances in electrocatalytic hydrogen evolution reaction (HER) and supercapacitors. Specifically, when the pine needle-derived carbon (activated at 800 °C) serves as a HER electrocatalyst, it exhibits a low onset potential (∼4 mV), a small Tafel slope (∼45.9 mV dec^-1) and a remarkable stability over long-term cycling. When evaluated as an electrode material for supercapacitors, the pine needle-derived carbon (activated at 900 °C) demonstrates high specific capacitance (236 F g^-1 at 0.1 A g^-1), remarkable rate capability (183 F g^-1 at even 20 A g^-1) and good long-term stability. Notably, the specific capacitance at 2.0 A g^-1 increased from ∼205 to ∼227 F g^-1 after cycling for 5000 times, owing to the further activation and wetting of the electrodes. This novel and low-cost biomass-derived carbon material is very promising for many applications, especially in electrocatalytic water splitting and supercapacitors.

Highly Efficient Retention of Polysulfides in "Sea Urchin"-Like Carbon Nanotube/Nanopolyhedra Superstructures as Cathode Material for Ultralong-Life Lithium-Sulfur Batteries

Despite high theoretical energy density, the practical deployment of lithium-sulfur (Li-S) batteries is still not implemented because of the severe capacity decay caused by polysulfide shuttling and the poor rate capability induced by low electrical conductivity of sulfur. Herein, we report a novel sulfur host material based on "sea urchin"-like cobalt nanoparticle embedded and nitrogen-doped carbon nanotube/nanopolyhedra (Co-NCNT/NP) superstructures for Li-S batteries. The hierarchical micromesopores in Co-NCNT/NP can allow efficient impregnation of sulfur and block diffusion of soluble polysulfides by physical confinement, and the incorporation of embedded Co nanoparticles and nitrogen doping (∼4.6 at. %) can synergistically improve the adsorption of polysulfides, as evidenced by beaker cell tests. Moreover, the conductive networks of Co-NCNT/NP interconnected by nitrogen-doped carbon nanotubes (NCNTs) can facilitate electron transport and electrolyte infiltration. Therefore, the specific capacity, rate capability, and cycle stability of Li-S batteries are significantly enhanced. As a result, the Co-NCNT/NP based cathode (loaded with 80 wt % sulfur) delivers a high discharge capacity of 1240 mAh g^-1 after 100 cycles at 0.1 C (based on the weight of sulfur), high rate capacity (755 mAh g^-1 at 2.0 C), and ultralong cycling life (a very low capacity decay of 0.026% per cycle over 1500 cycles at 1.0 C). Remarkably, the composite cathode with high areal sulfur loading of 3.2 mg cm^-2 shows high rate capacities and stable cycling performance over 200 cycles.

All-Inorganic Perovskite Solar Cells

The research field on perovskite solar cells (PSCs) is seeing frequent record breaking in the power conversion efficiency (PCE). However, organic-inorganic hybrid halide perovskites and organic additives in common hole-transport materials (HTMs) exhibit poor stability against moisture and heat. Here we report the successful fabrication of all-inorganic PSCs without any labile or expensive organic components. The entire fabrication process can be operated in ambient environment without humidity control (e.g., a glovebox). Even without encapsulation, the all-inorganic PSCs present no performance degradation in humid air (90-95% relative humidity, 25 °C) for over 3 months (2640 h) and can endure extreme temperatures (100 and -22 °C). Moreover, by elimination of expensive HTMs and noble-metal electrodes, the cost was significantly reduced. The highest PCE of the first-generation all-inorganic PSCs reached 6.7%. This study opens the door for next-generation PSCs with long-term stability under harsh conditions, making practical application of PSCs a real possibility.

Hierarchical porous nitrogen-rich carbon nanospheres with high and durable capabilities for lithium and sodium storage

To improve the energy storage performance of carbon-based materials, considerable attention has been paid to the design and fabrication of novel carbon architectures with structural and chemical modifications. Herein, we report that hierarchical porous nitrogen-rich carbon (HPNC) nanospheres originating from acidic etching of metal carbide/carbon hybrid nanoarchitectures can be employed as high-performance anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The structural advantages of HPNC nanospheres are that the exceptionally-high content of nitrogen (17.4 wt%) can provide abundant electroactive sites and enlarge the interlayer distance (∼3.5 Å) to improve the capacity, and the large amount of micropores and mesopores can serve as reservoirs for storing lithium/sodium ions. In LIBs, HPNC based anodes deliver a high reversible capacity of 1187 mA h g^-1 after 100 cycles at 100 mA g^-1, a great rate performance of 470 mA h g^-1 at 5000 mA g^-1, and outstanding cycling stabilities with a capacity of 788 mA h g^-1 after 500 cycles at 1000 mA g^-1. In SIBs, HPNC based anodes exhibit a remarkable reversible capacity of 357 mA h g^-1 at 100 mA g^-1 and high long-term stability with a capacity of 136 mA h g^-1 after 500 cycles at 1000 mA g^-1.

Hierarchical Ternary Carbide Nanoparticle/Carbon Nanotube-Inserted N-Doped Carbon Concave-Polyhedrons for Efficient Lithium and Sodium Storage

Here, we report a hierarchical Co₃ZnC/carbon nanotube-inserted nitrogen-doped carbon concave-polyhedrons synthesized by direct pyrolysis of bimetallic zeolitic imidazolate framework precursors under a flow of Ar/H₂ and subsequent calcination for both high-performance rechargeable Li-ion and Na-ion batteries. In this structure, Co₃ZnC nanoparticles were homogeneously distributed in in situ growth carbon nanotube-inserted nitrogen-doped carbon concave-polyhedrons. Such a hierarchical structure offers a synergistic effect to withstand the volume variation and inhibit the aggregation of Co₃ZnC nanoparticles during long-term cycles. Meanwhile, the nitrogen-doped carbon and carbon nanotubes in the hierarchical Co₃ZnC/carbon composite offer fast electron transportation to achieve excellent rate capability. As anode of Li-ion batteries, the electrode delivered a high reversible capacity (∼800 mA h/g at 0.5 A/g), outstanding high-rate capacity (408 mA h/g at 5.0 A/g), and long-term cycling performance (585 mA h/g after 1500 cycles at 2.0 A/g). In Na-ion batteries, the Co₃ZnC/carbon composite maintains a stable capacity of 386 mA h/g at 1.0 A/g without obvious decay over 750 cycles and a superior rate capability (∼500, 448, and 415 mA h/g at 0.2, 0.5, and 1.0 A/g, respectively).

Li3V2(PO4)3 encapsulated flexible free-standing nanofabric cathodes for fast charging and long life-cycle lithium-ion batteries

Lithiated transition metal phosphates with large theoretical capacities have emerged as promising cathode materials for rechargeable lithium-ion batteries. However, the poor kinetic properties caused by their low intrinsic electronic and ionic conductivity greatly hinder their practical applications. In this work, we demonstrate a novel strategy to prepare monoclinic lithium vanadium phosphate nanoparticles implanted in carbon nanofibers as the cathodes of Li-ion cells with high capacity, flexibility, long cycle stability and significantly improved high-rate performance. The composite nanofibers were obtained by electrospinning using polyacrylonitrile and Li3V2(PO4)3 nanoparticles, followed by annealing and coating with a thin layer of carbon by plasma enhanced chemical vapor deposition. The Li3V2(PO4)3 nanocrystals with the monoclinic phase were uniformly distributed in the composite nanofibers. The electrochemical performances of the as-prepared binder-free fibrous cathodes were characterized by potentiostatic and galvanostatic tests. At the rate of 0.5 C in the range of 3.0-4.3 V, the composite displayed an initial discharge capacity of 128 mA h g(-1) (96.2% of the theoretical capacity). A discharge capacity of 120 mA h g(-1) was observed even at a high rate of 10 C, and a capacity retention of 98.9% was maintained after 500 cycles at 5 C, indicating excellent high-rate capability and capacity retention. Compared to the control samples without a carbon outer-layer, the composite nanofibers with carbon coating demonstrated much better electrochemical performances. It indicates that the carbon coating can further protect the structural integrity of nanofabric electrodes during the charge/discharge processes without hindering the Li-ion mobility and also can prevent undesired side reactions with an electrolyte, thus greatly improving the rate performance and cyclic stability of the cathode.

Effects of solvents on the intrinsic propensity of peptide backbone conformations

We investigated the effects of solvents on the intrinsic propensity of peptide backbone conformations based on molecular dynamics simulations. The results show that compared with pure water, aqueous urea decreases the helix propensity. In comparison, methanol decreases the polyproline II (PPII) propensity. Such a solvent dependence of the intrinsic propensity of the backbone conformation is correlated with the solvent dependence of the hydration of the backbone groups and the formation probability of the local intrapeptide hydrogen bonds. Aqueous urea which has low ability to stabilize the local intrapeptide hydrogen bonds disfavors the helical conformation. Whereas, methanol which has low ability to hydrate the backbone groups disfavors the polyproline II conformation. In addition, the solvent effects can be further modulated by the side chains of the peptides. The solvent effects of the intrinsic propensity of peptide backbone conformations observed in this work suggest that changing the intrinsic propensity of the protein backbone conformations can partly contribute to the solvent-induced protein structure and dynamics variations. These results will be useful in understanding the solvent dependence of the conformational distributions of the unfolded proteins or peptides (or intrinsically disordered proteins) in which the global tertiary interactions are less important than that in the well-folded proteins.

Effects of hydrophobicity and anions on self-assembly of the peptide EMK16-II

Effects of hydrophobic and electrostatic interactions on the self-assembling process of the ionic-complementary peptide EMK16-II are investigated by atomic force microscopy imaging, circular dichroism spectra, light scattering, and chromatography. It is found that the hydrophobicity of the peptide promotes the aggregation in pure water even at a very low concentration, resulting in a much lower critical aggregation concentration than that of another peptide, EAK16-II. The effect of anions in solution with different valences on electrostatic interactions is also important. Monovalent anions (Cl(-) and Ac(-)) with a proper concentration can facilitate the formation of peptide fibrils, with Cl(-) of smaller size being more effective than Ac(-) of larger size. However, only small amounts of fibrils, but plenty of large amorphous aggregates, are found when the peptide solution is incubated with multivalent anions, such as SO(4)(2-), C(6)H(5)O(7) (3-), and HPO(4)(2-). More importantly, by gel filtration chromatography, the citrate anion, which induces a similar effect on the self-assembling process of EMK16-II as that of SO(4)(2-) and HPO(4)(2-), can interact with two or more positively charged residues of the peptide and reside in the amorphous aggregates. This implies a "salt bridge" effect of multivalent anions on the peptide self-assembling process, which can interpret a previous puzzle why divalent cations inhibit the formation of ordered nanofibrils of the ionic-complementary peptides. Thus, our results clarify the important effects of hydrophobic and electrostatic interactions on the self-assembling process of the ionic-complementary peptides. These are greatly helpful for us to understand the mechanism of peptides' self-assembling process and protein folding and aggregation.