ABSTRACT Maintaining reliable physical and electrical contact at the cathode–current collector junction remains a critical yet underexplored challenge in sodium‐ion batteries (SIBs). In particular, Na 3 V 2 (PO 4 ) 3 (NVP) cathodes undergo ∼8% volumetric fluctuations during biphasic (de)sodiation, progressively deteriorating the weak van der Waals‐governed interface between the polyvinylidene fluoride (PVDF) binder and the aluminum substrate, causing electrical isolation and capacity loss. Despite the widespread industrial use of carbon‐primed current collectors, a systematic understanding of their reinforcement mechanisms has been lacking. Herein, we elucidate three synergistic anchoring mechanisms through multi‐scale characterization. The carbon primer enhances surface roughness to promote mechanical interlocking, provides a compliant interlayer accommodating cyclic volumetric strain without debonding, and establishes electrostatic bridging between carboxylate functional groups and the fluorinated polymer backbone, as independently confirmed by Fourier transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). Control experiments verify that the performance bottleneck lies at the junction rather than in bulk electronic conductivity, while cross‐sectional wavelength‐dispersive spectroscopy mapping reveals that junction integrity governs sodiation uniformity throughout the electrode thickness. The primer‐integrated NVP//hard carbon full cells retain 88.7% capacity after 300 cycles, establishing a design framework for reliable cathode–current collector junctions in polyanion‐based energy storage systems.
ABSTRACT Helical polymers, central to many bioactive molecules and polymers, offer distinctive functional properties, yet the precise synthesis and atomic‐level characterization of artificial helical covalent polymers (HCPs) remain challenging. Here, we demonstrate that soft organic counter cations, combined with dynamic spiroborate chemistry, enable the rapid synthesis of hydrogen‐bonded, single‐crystal HCPs, significantly reducing polymerization times compared with analogous systems containing alkali metal cations. Single‐crystal X‐ray diffraction of HCPs prepared from amines or pyridine with their conjugate acid pK a values ranging from 4.63 to 10.71 revealed closely related hydrogen‐bonded helical backbones associated with nearby organic counter cations. Importantly, counter‐cation acidity strongly influences polymerization kinetics and the resulting helical architectures, establishing a previously underexplored strategy for controlling HCP formation. Beyond structural control, these materials exhibit promising solid‐state proton‐conducting properties, with HCP‐TFEA achieving a proton conductivity of 2.8 × 10 −3 S cm −1 at 70°C and 97% relative humidity. These findings demonstrate that rational counter‐cation selection provides an effective approach to accelerate HCP synthesis while simultaneously tuning polymer structure and function, offering new opportunities for the design of dynamic helical polymeric materials.
ABSTRACT The electronic properties of active M(O)OH catalysts can be effectively modified by tailoring the characteristics of their corresponding precatalysts. Herein, we report a coordination site‐modulated precatalyst to access active catalysts for efficient electrocatalytic urea oxidation in an anion exchange membrane (AEM) electrolyzer. A two‐dimensional NiFe‐coordination polymer (NiFe‐2D) was constructed via selective site engineering using hydrazine. Upon electrochemical reconstruction, NiFe‐2D was transformed into an active Fe‐Ni(O)OH catalyst (AC‐2D). X‐ray absorption spectroscopy (XAS) confirmed the changes in the coordination and electronic environment of AC‐2D with a tuned spin state. Remarkably, AC‐2D delivered a current density of 100 mA cm −2 at 1.50 V vs. RHE for the oxygen evolution reaction (OER) and 1.40 V vs. RHE for the urea oxidation reaction (UOR). AC‐2D also delivered outstanding performance in an AEM electrolyzer, achieving a current of 4 A at 2.9 V cell voltage and maintaining operation for over 8 days for UOR‐assisted water splitting. In situ electrochemical impedance spectroscopy (EIS) and kinetic analysis suggested facile charge transfer during OER and UOR in AC‐2D. In situ Raman studies revealed that Ni 4+ species were identified as the main active centers for OER, while Ni 3+ species served as the catalytic sites for UOR.
ABSTRACT Antibody‐guided therapeutics, including antibody‐drug conjugates and radiopharmaceuticals, efficiently deliver payloads to tumor lesions, but the weeks‐long half‐life of antibodies promotes accumulation in normal tissues, increasing the risk of off‐target toxicity. Although conventional linkers generally provide systemic stability, recent studies indicate that retention of intact antibody‐guided conjugates in normal tissues can cause chronic toxicity. Here, we report an antibody‐guided delivery platform leveraging the pH‐responsive properties of i‐motif functional nucleic acids (iM) for targeted chemo‐ and radiotherapy. Using trastuzumab as the targeting moiety, the platform (Tra‐iM) achieves selective payload delivery. Within the acidic tumor microenvironment, the i‐motif forms a stable quadruplex, promoting effective payload accumulation in tumor lesions. Under physiological conditions, nuclease‐sensitive linear i‐motif structures trigger rapid disassembly of Tra‐iM, generating hydrophilic nucleic acid fragments that minimize off‐target penetration and facilitate clearance of hydrophobic payloads. Fluorescence and PET imaging showed reduced normal‐organ retention and faster clearance of the labeled payload‐bearing components. Therapeutic evaluations demonstrate that Tra‐iM preserves targeted delivery and efficacy while markedly reducing hematologic and hepatic toxicity after high‐dose administration. This strategy significantly enhances the biosafety of antibody‐guided therapeutics and highlights the potential of metabolite‐regulated delivery platforms to advance targeted nanomedicine.
ABSTRACT Transition metal dichalcogenide (TMD) lateral heterostructures provide unique platforms to study nanoscale physics, but progress is limited by the difficulty of producing high‐quality interfaces, which require atomic‐precision growth rather than simple stacking. We report a controllable two‐step chemical vapor deposition (CVD) process for directed epitaxy growth of MoS 2 /WS 2 monolayer lateral heterostructures. Atom‐resolution scanning tunneling microscopy measurements demonstrate an atomically sharp, defect‐free MoS 2 /WS 2 interface formed along the sulfur zigzag edge of MoS 2 , indicating an atomic‐substitution‐nucleation growth mechanism. Domain sizes of both MoS 2 and WS 2 can be precisely tuned from several to hundreds of micrometers. The zig‐zag interface creates an intermediate energy level at the junction, prolonging photogenerated carrier recombination lifetimes, in agreement with theoretical band‐structure calculations. This work establishes a scalable synthesis route to high‐quality TMDs lateral heterostructures with an atomic‐scale shape interface and tunable domain sizes, accelerating the applications in electronic and optoelectronic devices.
