WO3 films are widely used in electrochromic devices owing to their high optical modulation and environmental stability. However, their practical application is hindered by sluggish redox kinetics and the ion trapping effect, leading to slow switching speeds and reduced cycling stability. To address these issues, we incorporated twodimensional layered Ti3C2Tx (T = -O, -F, and-OH), known for its high conductivity, and WO3.2H2O nano-sheets to form a composite film with dual functionalities of electrochromism and infrared stealth. The optimized WO3.2H2O/Ti3C2Tx composite film exhibits a significantly improved optical modulation of 58.0 % at 700 nm), rapid switching speeds (colored/bleached times, 9.2 s/1.6 s), and enhanced cycling stability (decay of 30.1/18.2 % in insertion/extraction charge density after 3000 s of cycling). These improvements originate from the synergistic effect of Ti3C2Tx and the crystalline water within the WO3.2H2O nanosheets. Together, they promote Li+ ion participation in redox reactions, accelerate the reaction kinetics, and reduce the ion trap effect in WO3 through reduced charge transfer resistance. Additionally, the incorporation of low-infrared-emissivity Ti3C2Tx provide a measurable 3.4 degrees C temperature shielding effect in colored state, further enhancing the composite film's infrared stealth performance. Owing to these advantages, the WO3.2H2O/Ti3C2Tx composite film shows great promise for applications in smart windows and thermal camouflage.

Despite the promise of hexagonal tungsten bronze (h-WO 3 ) as a proton storage host due to its 3.67 Å tunnels and Grotthuss conduction mechanism, its practical application remains limited by irreversible H + trapping, structural degradation, and sluggish kinetics. To overcome these limitations, we developed a tunnel cation engineering strategy by precisely pre-embedding Na + , K + , or NH 4 + ions into h-WO 3 tunnels via controlled use of sulfate precursors (Na 2 SO 4 , K 2 SO 4 , (NH 4 ) 2 SO 4 ). Structural characterizations confirmed that Na + pre-embedding yielded optimal lattice matching (0.3842 nm), minimizing distortion, while K + and NH 4 + induced lattice strain and disorder. Electrochemical tests demonstrated that Na + -embedded h-WO 3 achieved excellent cycling stability (99% capacity retention after 100 cycles at 100 C) by mitigating due to framework collapse. Although K + /NH 4 + -doped tungsten bronze nanowires exhibit higher H + storage capacity, their stability degradation caused by structural defects and reduced dimensions makes the Na + -embedded h-WO 3 with an ordered crystalline lattice more advantageous in balancing capacity and durability. Ex situ XRD revealed a two-stage proton storage mechanism in Na + -embedded h-WO 3 : bare H + insertion (0.3 V to −0.05 V) led to gradual lattice expansion, whereas hydrated H 3 O + insertion (−0.05 V to −0.4 V) triggered rapid ab-plane expansion. This study established a ‘pre-embedded cation-lattice strain-performance’ correlation, offering a new paradigm for designing high-stability proton storage materials.

Tungsten oxide, a promising electrochromic material for smart windows, faces limitations in practical applications due to its inherent low conductivity and sluggish switching kinetics. To address these challenges, this study proposes a composite architecture by integrating hexagonal tungsten oxide nanowires with Ti3C2TX MXene, a two-dimensional material renowned for its superior ionic and electronic conductivity. The resulting hexagonal tungsten oxide nanowires/Ti3C2TX MXene electrochromic device demonstrates significantly enhanced performance, achieving an optical modulation amplitude of 59.76% -a 10.35% improvement compared to the pure hexagonal tungsten oxide counterpart. Notably, the composite device exhibits accelerated switching kinetics, with bleaching and coloration times reduced by 22.2% (2.8 s) and 18.1% (13.6 s), respectively. Furthermore, the large-area flexible electrochromic window (8 x 8 cm2) fabricated via a scalable spray-coating technique demonstrates dual-functional capabilities: (1) Near infrared Solar thermal shielding performance in the colored state, and (2) X-band (8-12.4 GHz) electromagnetic interference shielding achieving a total shielding effectiveness of 12.8 dB in the colored state. This work not only establishes a novel strategy for developing high-performance dual-functional electrochromic devices, but also reveals their potential for next-generation energy-efficient smart windows with integrated electromagnetic protection functionalities.

Herein, we report a modular and efficient silver-catalyzed domino radical bicyclization of N-phenyl-4-pentenamides with 2-(allyloxy)benzaldehydes and 2-allylbenzaldehydes, enabling the selective synthesis of γ-lactam-containing chroman-4-one and indanone hybrids in moderate to good yields. This transformation proceeds under mild conditions and features high step- and atom-economy, constructing two C-C bonds and one C-N bond in a single step within 30 min. Notably, it affords five-membered carbocycles or six-membered oxygen heterocycles with excellent regioselectivity.

Hydrogen ion has been extensively studied as a charge carrier in electrochemical energy storage devices due to its minimal ionic radius and abundant reserves. Among various candidate materials, molybdenum trioxide (MoO3) stands out as a promising electrode material owing to its excellent chemical stability and ultrahigh theoretical storage capacity. However, its practical application is hindered by a narrow potential window as a hydrogen-ion electrode and a low operating voltage caused by aqueous electrolyte decomposition. In this study, MoO3 nanoribbons with significant number of oxygen vacancies were synthesized via a simple hydrothermal method, which exhibit notable backward shift in the hydrogen evolution potential, three-proton intercalation/deintercalation process, and then a very noticeable enhancement in hydrogen-ion storage capacity during electrochemical testing in the aqueous electrolyte. It was also found that tungsten(W) doping in a specific amount can enrich the oxygen vacancies in MoO3 nanoribbons and then further enhance their hydrogen-ion storage performance. Remarkably, the W-doped MoO3 nanoribbons with a nominal molar ratio of 3% demonstrate an exceptional specific capacity of 390.8 mA h/g at a current density of 100 C (40 A/g). This study might highlight the significant impact of oxygen vacancy and tungsten(W) doping on the microstructures and electrochemical properties of MoO3 nanoribbons and provide valuable insights for the design and development of high-performance electrode materials for hydrogen-ion batteries.

The common aqueous metal ion capacitors, such as those of Al3+ and K+ ions, encounter challenges like low capacity, limited rate capability, and poor cycling stability, thereby largely impeding their practical applications. Here, we report the utilization of W18O49 with multi-type tunnels, abundant oxygen vacancies, and low crystallinity for high-performance aqueous NH4+ ion capacitor. We found that despite the relatively large radius (0.143 nm) of NH4+ ions, W18O49 achieves a capacity of 87.3 mAh/g in (NH4)2SO4 solution. This is because the NH4+ ions and the O atoms on the multi-type tunnels of W18O49 form hydrogen bonds, thereby mediating their insertion into the tunnels, and meanwhile, the abundance oxygen vacancies act as active sites for redox reaction. Moreover, W18O49 also demonstrates higher rate capability (a decrease of only 17.1 mAh/g from 20 to 100 C) as the multi-type tunnels provide efficient transport pathways for NH4+ ions, while its low crystallinity enhances its interlayer spacing and thereby accelerates the transport of ions. Finally, the hydrogen bond-mediated insertion/ deinsertion of the NH4+ ions effectively avoids the irreversible phase transition of the W18O49 (which has a high capacitance contribution ratio over 94 %), thereby improving its cycling stability (with only a 4.4 % degradation after 200 cycles). With these advantageous characteristics, W18O49 show great potential for practical highperformance aqueous NH4+ ion capacitors.

Halogenated γ-lactams are valuable synthetic targets, but efficient methods for accessing chloro- and bromo-substituted analogues remain elusive. Here we describe a copper-catalyzed radical halocyclization of N-4-pentenamides that enables one-step access to chloro- and bromo-substituted γ-lactams using inexpensive tetrabutylammonium chloride (TBACl) and tetraethylammonium bromide (TEAB) as halogen sources. The reactions proceed under mild conditions to afford desired products in good to excellent yields with a broad substrate scope and functional group tolerance. Preliminary mechanistic studies suggest a radical pathway involving a Cu(I)/Cu(II)/Cu(III) catalytic cycle and 5-exo-trig cyclization.

Low-symmetry two-dimensional (2D) materials have attracted significant attention for polarization-sensitive photodetection due to the optoelectronic anisotropy. Here, we demonstrated the strong in-plane anisotropy of In2Te5 through electron density distribution calculations based on density functional theory and developed a polarization-sensitive photodetector. The photodetector shows a responsivity of 171.16 mA/W and a response time of 0.42 s under visible light illumination. Additionally, it presents a polarization-sensitive photoresponse with a dichroic ratio of 1.34. Our work reveals the anisotropic optoelectronic properties of In2Te5, potentially stimulating research interest in Group III-VI 2D materials (Pentatelluride M2Te5, M = Al, Ga, In, etc.).

Aqueous hydrogen ion batteries are emerging as a promising solution for large-scale energy storage due to their smallest ionic size and abundant availability. Among various materials, molybdenum trioxide has garnered significant attention for its rapid hydrogen ion insertion/extraction kinetics and high theoretical storage capacity. However, the mechanisms underlying the swift ion transport and high-capacity storage in MoO3 remain insufficiently understood, which necessitates further investigation to fully explore its potential applications in energy and information technologies. In this study, the electrochemical behavior of the hexagonal and orthorhombic MoO3 nanowires with nearly identical morphologies synthesized via the hydrothermal method has been thoroughly characterized, which exhibits lattice structure-sensitive hydrogen ion storage performance. The experimental results demonstrate that the charge storage process transitions from a capacitive- to diffusion-controlled mechanism, and the storage capacity increases from 155 to 279.6 mA h/g at a current density of 100 C when the lattice structure of the MoO3 nanowires gradually changes from hexagonal to orthogonal. The alpha-MoO3 nanowire electrode exhibits reduced polarization, a lower interfacial barrier, and higher ion diffusion coefficients, which might be attributed to the differences in the lattice structure. In the lattice of h-MoO3, the hydrogen ion storage sites are mainly distributed within the internal hexagonal channels, while alpha-MoO3 can offer much more instantly accessible storage sites due to its open structure vertical to the nanowire axis formed based on van der Waals force. Consequently, this study provides some insights into the rapid transport and large capacity storage of hydrogen ions in the MoO3 lattice and then suggests a mechanism for regulating hydrogen ion transport and storage for fast and high-capacity storage of energy.

The shear crystal structure through metal doping can effectively promote the transport speed of ions and electrons in metal oxides, which has important dynamic significance for the design of high-performance energy storage materials. Herein, a 3D urchinlike niobium tungsten oxide (NWO) nanostructure as an efficient hydrogen ion storage material is reported for the first time, which exhibits a capacity of 88mAh g −1 at 20 °C (1 °C = 100 mA g −1 ). The large specific capacity of the 3D urchinlike NWO nanostructure is ascribed to the reversible reaction of a great quantity of W 6+ , W 5+ and W 4+ in the process of protonation and deprotonation processes. In addition, hydrogen ions can still be stored in large and stable quantities, even at rates as high as 100 °C (75 mAh g −1 at 100 °C). The improvement of hydrogen ion storage properties is arising from an optimized morphology of niobium tungsten oxide via tuning of the crystal structure. The high specific superficial area 3D urchinlike shape with rich one-dimensional nanostructures significantly shortens charge-carrier transport distances, ensuring rapid interfacial electronics movement to polish up ion storage kinetics. Consequently, this crystallographic shear structure strategy to boost hydrogen ion storage capacity may be universal and is likely to pave the way toward highly capacity hydrogen ion energy storage systems.

Hydrated tungsten trioxide has been investigated extensively and was demonstrated to exhibit rapid proton conduction. For the purpose of fabricating electrochemical energy storage devices with higher power density, it is crucial to figure out the proton transport and storage mechanisms exactly. In this work, we have characterized the electrochemical performance and microstructure evolution during electrochemical reaction of hexagonal hydrated tungsten trioxide nanorods with different lattice water contents by ex situ XRD and Raman. With the decrease of lattice water content, the contribution of the capacitive charge storage decreases evidently, and both lattice distortion and lattice disorder increase significantly in the process of ion intercalation. Therefore, we suppose that the existence of lattice water in tungsten oxide offers a much more flexible mechanical deformation during the process of proton insertion and proton diffuse in tungsten trioxide based on the bridging oxygen mechanism. Besides that, proton prefer to be inserted/extracted in/from hydrated tungsten trioxide in the form of hydrated hydrogen ions (H 3 O + ) when the lattice water decreases apparently. These results provides significant insight towards the understanding of proton transport in hydrated tungsten trioxide and can serve as a pattern for the compositional design of cathode materials for proton battery and supercapacitor.

Ion doping in the process of synthesis can modulate the morphology, lattice structure, and electronic structure of metal oxide nanostructures, and then regulate the ion transport path, electron and ion conductivity, and ion storage site in the electrochemical energy storage process, which has important significance for the design of electrochemical energy storage materials with high-performance. In this work, three-dimensional (3D) urchin-like Mo-doped WO2.72 nanostructures have been synthesized based on the simple hydrothermal method. By adjusting the molybdenum ion doping concentration, we found that the as-synthesized 12.67 at% Mo-doped sample exhibits excellent hydrogen ion storage performance with high-rate capability and long cycle life. The electrode capacity was enhanced from 67.1mAh/g to 96.1mAh/g at 20C (1C = 100mA/g) and was able to maintain 98.8% of the initial capacity after 100 cycles at 100C. Mo-doping in a certain concentration range (less than 22.50 at%) makes the diameters of the one-dimensional (1D) WO2.72 nanostructures smaller while maintaining the 3D urchin morphology, which increases the specific surface area and reduces the length of ion diffusion path. Furthermore, the oxygen vacancy concentration in tungsten oxide increases significantly with Mo-doping, which facilitates proton diffusion and charge transport and increases proton storage sites and storage capacity. Therefore, multivalent metal ion doping such as Mo might be an effective means for optimizing the electrochemical energy storage performance of metal oxide.

We report a comprehensive analysis of the Electromagnetic (EM) properties of graphene aerogel-based shielding materials prepared by freeze casting. Controlling the freeze casting temperature allows for tailoring the pore sizes of graphene aerogels, which further affects the permittivity and EM shielding properties. To protect the aerogel structures from collapsing during high temperature heat-treatment, we used Melamine sponge (MS) as a supporting strut. Through a comparison with bare aerogels, we find that the presence of MS can significantly modify both the reflection and absorption performances and that an absorption-dominated shielding material can be obtained. After heat-treatment at 1000 degrees C for two hours, the MS-supported aerogel sample (MS-aero) showed a shielding efficiency of 55.8 dB. Our work shows that the material composition and the microstructural architecture of aerogels crucially influence their electromagnetic shielding efficiency.

We studied the intercalation chemistry of graphitic carbon nitride (gCN), combining theory and experimental methods. A series of new alkali-ethylenediamine-gCN products were prepared using a one-po...

We report a versatile method to make liquid metal composites by vigorously mixing gallium (Ga) with non-metallic particles of graphene oxide (G-O), graphite, diamond, and silicon carbide that display either paste or putty-like behavior depending on the volume fraction. Unlike Ga, the putty-like mixtures can be kneaded and rolled on any surface without leaving residue. By changing temperature, these materials can be stiffened, softened, and, for the G-O-containing composite, even made porous. The gallium putty (GalP) containing reduced G-O (rG-O) has excellent electromagnetic interference shielding effectiveness. GalP with diamond filler has excellent thermal conductivity and heat transfer superior to a commercial liquid metal-based thermal paste. Composites can also be formed from eutectic alloys of Ga including Ga-In (EGaIn), Ga-Sn (EGaSn), and Ga-In-Sn (EGaInSn or Galinstan). The versatility of our approach allows a variety of fillers to be incorporated in liquid metals, potentially allowing filler-specific "fit for purpose" materials.

Porous Cu/Ni foils were made by electroplating Ni on Cu foils and used as templates for chemical vapor deposition growth of porous graphene foam. The walls in the graphene foam were found to be two to five graphene layers thick, interconnected to form a low-density porous network with a wide distribution of pore sizes and a high electrical conductivity. A comprehensive comparison with previously studied materials for electromagnetic interference (EMI) shielding showed that this graphene foam is among the best EMI shielding materials; its specific EMI shielding effectiveness (>720 dB cm3 g−1) and absolute effectiveness (>45,000 dB cm2 g−1) are superior to those of most other materials. This graphene foam has a large absorption capacity for various organic solvents and oils and adsorbs them within seconds. The synthesis strategy should provide a general approach for generating other 3D porous structures, including those based on a variety of known 2D materials, for various applications.

A sodium-ethylenediamine graphite intercalation compound (Na(ethylenediamine)C15: "GIC") made from graphite flakes was used to study the microwave absorption performance of a GIC for the first time. Compared with the pristine graphite flakes, the neighboring layers in this GIC are pillared by Na(ethylenediamine)+ and possess a larger layer distance and improved electrical conductivity. Owing to the electrical conductivity of this GIC, only half of the loading content, compared to graphite flakes, is needed to achieve an outstanding absorption of -75.6 dB at 9.25 GHz (10.0 wt % GIC in paraffin in a 4.0 mm thick sample), but for graphite, 20.0 wt % is required for an absorption of -37.6 dB.

Although substrate composition can influence the chemical reactivity of graphene, substrate lattice orientation provides a valuable alternative. The effect of Cu surface orientation on the reactivity of graphene was explored through a reductive transformation. Among the substrates tested, only Cu(111) led to the efficient, fast and uniform functionalization of graphene, as demonstrated by Raman mapping, and this arose from compressive strain induced by Cu(111). Functionalization effectively relaxes the strain, which can be subsequently reintroduced after thermal treatment. Theoretical calculations showed how compression facilitates the reduction and hybridization of carbon atoms, while coupling experiments revealed how kinetics may be used to control the reaction. The number of graphene layers and their stacking modes were also found to be important factors. In a broader context, a description of how graphene undergoes chemical modification when positioned on certain metal substrates is provided.

The electric vehicle and energy storage industries will generate over one-million tons per annum of lithium-ion for recycling in the next decade. There are significant technology gaps in the recovery of lithium-ion battery materials that threaten the sustainability of these industries. Cathode healing is introduced here as a new approach to produce low cost (i.e. < $10/kg), recycled, battery grade electrode material. The soft-chemical treatment non-destructively recycles cathodes. Two examples are shown in this work: LiNi0.5Co0.2Mn0.3O2 and LiNi0.6Co 0.2Mn0.2O2 (NCM 523 and NCM 622). The cathodes were harvested from end-of-life cells and further processed with cathode-healing methods to reproduce recycled electrodes with performance equivalent to the original manufactured baseline material. The so-called healed cathodes were built into 2Ah test cells and compared side-by-side with the baseline. Healed NCM 523 performed like the baseline, recording over 2,100 charge-discharge cycles to reach 80% of original capacity. The cathode healing process was modified to fully recover end-of-life NCM 622. Powder X-ray diffraction and X-ray photoelectron spectroscopy data support the lithium capacity measurements with structural models. These analyses show that cathode healing reverses cation mixing by oxidizing nickel to reproduce well-ordered, high-capacity material. These examples show the technical feasibility and low-cost opportunity for cathode healing to enable sustainability in the electric vehicle and energy storage industries.

There has been a major effort recently to develop new rechargeable sodium-ion electrodes. In lithium ion batteries, LiC6 forms from graphite and desolvated Li cations during the first charge. With sodium ions, graphite only shows a significant capacity when Na+ intercalates as a solvated complex, resulting in ternary graphite intercalation compounds (GICs). Although this chemistry has been shown to be highly reversible and to support high rates in small test cells, these GICs can require >250% volume expansion and contraction during cycling. Here we demonstrate the first example of GICs that reversibly sodiate/desodiate without any significant volume change. These pillared GICs are obtained by electrochemical reduction of graphite in an ether/amine co-solvent electrolyte. The initial gallery expansion, 0.36 nm, is less than half of that in diglyme-based systems, and shows a similar capacity. Thermal analyses suggest the pillaring phenomenon arises from stronger co-intercalate interactions in the GIC galleries.