Latest ArticlesLithium/fluorinated graphite (Li/CFx) primary batteries with great energy density advantages still struggle to realize large-scale applications, due to the sluggish cathode reaction kinetics accompanied by poor rate capability and power density. One key challenge arises from the inert electronic structure of CFx predominated by covalent C–F bond, which results in poor intrinsic electronic conductivity. To address this issue, cathode surface activation engineering is proposed to modify CFx with hybrid transitional metal oxide/carbon layer, which is derived by one-pot pyrolysis of structurally designable metallic ionic liquids (Bmim[MCln], M = Fe, Al, Cu, Zn, etc.). Generally, the presence of metal oxides induces generation of highly conductive semi-ionic C–F species, cooperating with abundant oxygen vacancies and carbon matrix to synergistically improve electronic/ionic conduction and accelerate CFx conversion kinetics, while the Bmim[FeCl4]-derived system is the optimal solution. As expected, the surface activated CFx cathode achieves nearly 4 times the power density (22,581 W/kg at 14 C) of pristine CFx and higher conversion depth. This metallic ionic liquid-derived surface activation design efficiently regulates the intrinsically inert electronic structure of CFx cathode, and widens its chemical design space of metal oxides as composite components, furthermore, providing a universal solution for electrodes faced with electronic conduction challenges.
The proton conduction mechanism of imidazole and its homologues within confined spaces has attracted much attention from researchers, which is highly beneficial for the development of novel proton exchange membranes. Traditionally, the hydrogen at the 1-position (H-1) on the nitrogen (N-1) of imidazole is seen as the exclusive source of mobile protons. However, we suggest that the 3-position nitrogen atom (N-3) can also generate mobile protons under hydrous conditions. This is because N-3 can form hydrogen bonds with water, which are particularly robust in confined spaces, thereby enhancing proton ionization from water and facilitating proton transfer. Based on this concept, 1-methylimidazole was introduced into a covalent organic framework (COF), resulting in a remarkable proton conductivity of 2.40 × 10–3 S/cm at 70 ℃ and 100% relative humidity. This performance is on par with that of COFs doped with imidazole, demonstrating the key role of N-3···H2O interactions within the framework in producing mobile protons and facilitating proton diffusion. Furthermore, this challenges the conventional viewpoint that H-1 of imidazole is the sole contributor to proton concentration, offering a new strategy for the preparation of high-performance proton conductors.
The limited stability of Pt-based catalysts as a result of irreversible support corrosion and Pt dissolution/aggregation remains a major barrier to the widespread deployment for Proton exchange membrane fuel cells. To overcome the issues, amorphous TaOx with corrosion-resistance was introduced to stabilize Pt nanoparticles in this work. Benefiting from the strong metal-support interaction, Pt oxidation and dissolution is suppressed through efficient electron transfer from the support. Optimized Pt/TaOx-C catalyst shows remarkable stability with voltage loss @0.8 A/cm2 of only 29 mV after 50k cycles accelerated durability test, which is much lower than the goal for DOE 2025 (30 mV after 30k cycles). Besides, the strong anchoring effect of the amorphous TaOx enables well dispersion of Pt with an ultra-small particle size of approximately 1.3 nm, reducing the local mass transfer resistance towards superior fuel cell performance of 2.29 W/cm2, which is higher than the commercial Pt/C of 1.56 W/cm2. This study offers a highly active and durable cathode electrocatalyst for fuel cells.
The electrocatalytic two-electron oxygen reduction reaction (2e– ORR) offers an environmentally friendly method for hydrogen peroxide (H2O2) production, yet the development of efficient and cost-effective electrocatalysts remains a significant challenge. Herein, we have synthesized Ni3N2 clusters anchored on N-doped carbon nanostructures (Ni3N2/NC) through a straightforward biomass-derived modification-pyrolysis method for efficient H2O2 production. Theoretical calculations reveal that the D-band center of Ni sites in Ni3N2/NC shows a downshift and successive state, which is beneficial to the formation of key *OOH intermediates and occurrence of subsequent reactions. Remarkably, Ni3N2/NC achieves a 2e– ORR selectivity of 91.65% and an onset potential of 0.69 V. When tested in a practical flow cell, Ni3N2/NC exhibits a Faradaic efficiency (FE) of 91.42% and attains a maximum H2O2 yield of 3.26 mol gcat−1 h−1 at 100 mA/cm2. Additionally, the FE remains above 85% during a 12 h constant current stability test at 40 mA/cm2, highlighting its potential for sustainable H2O2 production.
Searching for new oxide-ion conductors is of great significance in energy-related technologies. Here we identified a novel barium tellurate, Ba10.55Te4.45O23.90, by chemical screening for superstructural oxide-ion conductors. Its crystal structure, solved from polycrystalline specimen by the combination of three-dimension electron diffraction, X-ray diffraction, and neutron diffraction, adopts a quadruple (4 × 4 × 4) cubic superstructure (Fm-3m, a = 17.30612(2) Å) and can be regarded as a derivative of ABO3 perovskite like (Ba1.75□0.25)ABaBWB'O5.75□0.25. The ordered A-site metal vacancies and disordered oxygen vacancies are responsible for the enlarged superstructure. The titled compound is indeed an oxide-ion conductor but shows rather low ionic conductivity, owing to the high inter-polyhedral energy barrier of ionic migration. The discoveries unveil a new structural type for oxide-ion conductor exploration, and will evoke performance improvement by chemical modification such as aliovalent substitution.
This study reveals the unique electrochemical mechanism of violet phosphorus (VP) as an anode material for lithium-ion batteries. Using solid-state nuclear magnetic resonance (NMR) spectroscopy, we detail the alloying reaction mechanism of VP during lithiation. While alloying behavior in black and red phosphorus has been widely studied, intermediate phases remain poorly understood due to complex phase transitions. Our precise NMR assignments link specific signals in VP to distinct atomic sites. The results show that [P8] cage atoms preferentially react with lithium in the early stages, while [P9] cages provide structural support. VP layered structure allows lithium ions to first intercalate between layers, followed by alloying reactions. These findings offer new insights into VP alloying mechanism, advancing the fundamental understanding of its potential in next-generation energy storage systems.
Hydrogel electrolytes are widely used in zinc-ion batteries (ZIBs) due to their advantages of regulating zinc deposition/stripping process, and limiting dendrite growth. However, their relatively poor ionic conductivity and mechanical properties remain significant obstacles to their practical application in ZIBs. Herein, the multi-component cross-linked polyacrylamide/carboxymethyl cellulose/agarose (PCA) hydrogel polymerized electrolytes are designed via a heat-initiated polymerization approach. The PCA hydrogel electrolytes exhibit high ionic conductivity of 38.78 mS/cm and excellent mechanical strength from 2.9 MPa to 5.6 MPa. Meanwhile, the ample hydroxyl (-OH) functional groups on the PCA hydrogel electrolytes chain can capture and anchor H2O molecules via hydrogen bonding, thus fundamentally regulating the coordination environment of Zn2+ and inhibiting side reactions. The combined effect of carboxyl (-COOH) groups and amino (-NH2) groups in PCA hydrogel electrolytes can induce the uniform deposition of zinc ions. Consequently, The Zn//Zn symmetrical cell assembled with this hydrogel electrolytes demonstrate excellent cycling stability over 2500 h at the current density of 1 mA/cm2. Furthermore, the Zn//MnO2/CNT full cell retains a specific capacity of 127.2 mAh/g after 1000 cycles at 1 A/g, with 97.8% capacity retention.
Tuning molecular chirality through external stimuli stands at the forefront of chemical science. Here, we systematically examine the stereodynamic properties of a series of Cu(Ⅱ)-based perovskite single crystals, CystaH2[CuCl(4-x)Brx] (CystaH2 = protonated cystamine cation, x = 0.74, 0.80, 1.05, 1.11, 1.18), which undergo a polar-to-nonpolar ferroelectric phase transition. In these compounds, the symmetry breaking structural change is governed by an unusually thermally driven P ↔ M helical inversion of the helical CystaH22+ organic cations. The conformational inversion can be substantially modulated by bromide doping. As the bromide content increases, the phase-transition temperature progressively shifts closer to room temperature, decreasing by up to 49 K. Detailed structural analyses reveal that the chiral inversion of CystaH22+ is highly sensitive to local chemical environments, and this doping strategy offers an effective route for precisely governing temperature-mediated chiral transformations, thereby expanding the design space for advanced chiral materials.
Azido molecules (azidos) have been extensively investigated for their potential as biomedical tools. However, the precise mechanism underlying their intracellular activation remains elusive. In this study, we adopted experimental and computational approaches to demonstrate that this activation mechanism is a photo-bioactivation process, facilitated by intracellular proteins that interact with azidos. Building on these findings, we developed a passive cell-specific fluorescence imaging tool for non-invasive cell tracking within three-dimensional (3D) scaffolds, an active-targeting subcellular organelle imaging system, and a controllable prodrug delivery platform that enables the spatiotemporal regulation of intracellular release and distribution of therapeutic agents. Overall, our study provides the first comprehensive elucidation of the cellular activation mechanism of azidos, which has significant implications for the development of a diverse array of photo-bioactivated tools and prodrugs.
Cancer vaccines have proven to be a powerful tool in anti-tumor immunotherapy, leveraging antigen-specific T-cell responses. The effective activation of the stimulator of the interferon gene (STING) protein signal pathway by natural or synthetic agonists leads to the creation of a pro-immune tumor microenvironment. Here, we report the preparation of ovalbumin (OVA) loaded cancer vaccines based on nanoemulsions, denoted as DMMF59-OVA, for the co-delivery of antigens and a STING agonist (MSA-2). The nanovaccines were obtained via encapsulation of MSA-2 into squalene phase, which was stabilized by surfactants and coated with OVA. Upon intramuscular administration, the engineered nanovaccine facilitates antigen internalization, maturation of antigen-presenting cells (APCs), and efficient activation of the STING pathway. These results in enhanced antigen-specific humoral and cellular immune responses that significantly inhibit tumor growth in an E.G7-OVA mouse model. The studies provide an avenue for the application of nanovaccine in tumor immunotherapy. Given the ease of preparation and tunable physicochemical properties, DMMF59-OVA represents a promising therapeutic nanovaccine for biomedical applications
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