The room‐temperature ferromagnetic Sr 3 YCo 4 O 12− δ (314‐SYCO) provides an ideal platform for investigating magnetic‐field‐assisted catalytic performance. Herein, a series of 314‐SYCO polycrystals were synthesized via a sol–gel route by systematically varying the sintering temperature (800, 1000, and 1200 °C) and duration (5–20 h) to elucidate the effects of thermal history on Co valence states, ferromagnetic properties, and magnetic‐field‐enhanced oxygen evolution reaction (OER) activity. At 1000 °C, extending the sintering duration from 5 to 20 h yields an ordered tetragonal phase, accompanied by a significant increase in the Co 3+ fraction from 73.3% to 98.6%. The Curie temperature reaches ~336 K at 15 h, while the 20 h sample exhibits a near‐saturation magnetization of 5.07 emu g −1 , nearly twice that of the 5 and 10 h samples. Under a 200 mT magnetic field, the OER kinetics exhibit a pronounced ferromagnetism‐dependent enhancement, leading to reductions in overpotential of 8.0–19.7 mV at 10 mA cm −2 . The sample sintered for 20 h exhibits the best performance, achieving a minimum overpotential of 343.8 mV together with a significant enhancement in intrinsic specific activity. Optimization of the sintering process effectively tunes the Co valence states and ferromagnetic ordering of 314‐SYCO, thereby enhancing magnetic‐field‐assisted OER activity.
Perovskite solar cells (PSCs) require dopant‐free hole transport materials (HTMs) to enable low‐cost, stable device architectures. This study introduces a bifunctional central acceptor engineering strategy on a tetrathiafulvalene (TTF) donor scaffold, in which five HTM candidates (BA1–BA5) were designed from the reference molecule BAR via central acceptor modification. A theoretical evaluation was performed at the B3LYP/6‐31G(d,p) level to assess their potential as HTMs for PSCs. The designed molecules exhibit strong optical absorption in the 812–1115 nm range in dichloromethane with higher oscillator strengths than BAR. The highest occupied molecular orbital–lowest unoccupied molecular orbital (LUMO) gap narrows from 3.18 eV in BAR to 1.29–1.82 eV in BA1–BA5, driven by LUMO stabilization, and decreased reorganization energies indicate more favorable charge transfer characteristics. BA3 shows low hole and electron reorganization energies; its ground‐state dipole moment increases up to 2.6‐fold, indicating enhanced molecular polarity and a stronger response to the solvent environment. Open‐circuit voltages estimated against the PC 61 BM reference acceptor range from 0.63 to 0.86 V. Among the series, BA2 and BA3 emerge as the promising candidates, combining favorable energy‐level alignment, excited‐state characteristics, and molecular‐level charge transfer indicators. These computational results establish central acceptor engineering as an effective strategy for tuning TTF‐based dopant‐free HTMs, and identify molecular targets for synthesis and device‐level validation.
Magnesium hydrides (MgH 2 ) have been extensively studied for solid‐state storage applications. However, the industrial scalability of MgH 2 is limited due to its high absorption/ desorption temperatures and poor kinetics. In this work, a Nb‐substituted Mg 2 Ni catalyst (Mg 2 Ni 0.8 Nb 0.2 ) was synthesized by the melt spinning technique. The Mg‐20 wt% of Mg 2 Ni 0.8 Nb 0.2 composites were prepared using the high‐energy ball milling technique. The composite desorbed around 5 wt% H 2 within 10 min at 300 °C, while retaining 97.88% of its initial absorption capacity after 20 cycles. Furthermore, the composites were hydrogenated for different times, 10, 20, and 30 min, to study the effect of hydrogenation time on the dehydrogenation behaviour of MgH 2 . Compared with pure MgH 2 , which exhibits an activation energy of 275.52 kJ/mol, the Mg–Mg 2 Ni 0.8 Nb 0.2 composites showed significantly reduced activation energies of 126.35, 131.66, and 100.78 kJ/mol after hydrogenation for 10, 20, and 30 min, respectively. The improved performance is attributed to partial Nb substitution, which enhances hydrogen dissociation and reduces the activation energy for breaking Mg–H bonds.
Layered double hydroxides (LDHs) with hollow structures offer high theoretical specific capacity and short ion diffusion pathways, making them promising supercapacitor materials. However, constructing hollow NiCo‐LDH remains challenging because it typically relies on template or special reaction conditions that are often harsh, and the conventional preparation of LDHs itself requires large amounts of alkaline reagents. Herein, we report an alkali‐free nickel‐ion‐directed replacement reaction using ZIF‐67 as self‐sacrificing template to fabricate hollow NiCo‐LDH nanocages. Enabled by a Kirkendall‐effect‐mediated conversion process, this green strategy yields hollow dodecahedral nanocages providing abundant electroactive sites and facilitating rapid ion transport. The optimized electrode delivers a high specific capacity of 466.14 mAh g −1 at 1 A g −1 and retains 314.99 mAh g −1 at 10 A g −1 . Kinetic analysis reveals that the capacitive contribution increases from 52.8% at 5 mV s −1 to 83.3% at 100 mV s −1 , demonstrating excellent surface‐controlled charge storage. An asymmetric supercapacitor (NiCo‐LDH//AC) achieves a maximum energy density of 38.7 Wh kg −1 at 179.8 W kg −1 and retains 26.5 Wh kg −1 at 1798 W kg −1 , and powers an LED for over 100 min. This work offers a green, alkali‐free route to hollow bimetallic LDHs and highlights the potential of sustainable synthesis for high‐performance supercapacitors.
Lithium‐ion polypropylene (PP) separators limit high‐energy Li‐ion batteries due to poor thermal stability, low wettability, and weak dendrite suppression. Metal–organic frameworks (MOFs) provide a viable solution through tunable pores, high surface area, and versatile surface chemistry. This review summarizes multiscale regulation strategies for MOFs‐modified PP separators. It classifies applicable MOFs into three topological types—ZIF, UiO, and HKUST—and analyzes their distinct mechanisms in enhancing ion transport and interfacial dynamics. Four primary fabrication techniques (coating, blending, in situ growth, and composite construction) are systematically compared for their suitability and performance outcomes. Key challenges remain, including high costs, poor interface compatibility, and insufficient long‐term stability. Future development requires integrating multiscale structural engineering, intelligent dynamic interfaces, and cost‐effective green manufacturing. This review offers a practical framework for designing advanced separators for next‐generation high‐safety, high‐energy‐density Li‐ion batteries.
