Science China Materials最新文献

Lithium–sulfur batteries suffer from rapid capacity decay due to polysulfide dissolution and lithium anode instability. Sulfurized poly(acrylonitrile) (SPAN), which chemically anchors sulfur within its polymer matrix, can effectively suppress polysulfide dissolution. Pairing SPAN with the graphite (Gr) anode can circumvent challenges associated with lithium metal and achieve prolonged cycle life. For developing such long-life sulfur-based batteries, it is of great significance to understand their cycling decay mechanism and establish a reasonable acceleration test model, since it is beneficial for quickly evaluating the cycle properties and optimizing battery designs. This study systematically investigates the electrochemical dynamics and capacity decay mechanism of SPAN∥Gr pouch cells cycled at 25–55 °C. Multiscale analyses reveal that capacity fade arises from active lithium loss and increased resistance, both of which would be accelerated by higher temperatures. Leveraging the consistent decay mechanism across temperatures, an accelerated aging model based on the Arrhenius equation is developed. This model could predict cycling parameters at specific temperatures and reduce testing time by 50%. These insights and the accelerated aging model may provide critical guidance for developing long-life sulfur-based batteries for practical applications.

Construction of metal-mediated redox sites is an appealing approach to enhance photocatalytic CO₂ reduction coupled with H₂O oxidation. However, conventional static redox sites generally lack spatiotemporal matching during reaction processes due to the constraints of rigid structure and the linear scaling relationship of adsorbed species. Herein, an alkanolamine-Ir synergistic system was developed, where flexible monoethanolamine (MEA) molecules function as molecular ferries to selectively adsorb CO₂ via carbamate formation, while adjacent Ir nanoparticles (NPs) serve as H spillover hubs that relay protons, creating spatiotemporal adaptability that synchronizes CO₂ reduction and water oxidation. In addition, time-resolved in situ spectroscopy directly captures the rapid transformation of carbamate intermediates concurrent with sustained IrOOH intermediates formation. Microkinetic modeling further demonstrates that the MEA-Ir modified system (M-Ir/ACN) creates interconnected H spillover networks between Ir NPs and MEA, facilitating efficient proton transport that drives *COOH formation with a favorable thermodynamic energy. As a result, the M-Ir/ACN achieves a 20-fold increase in CO production compared to the pristine sample while maintaining high stability throughout 45 h of continuous operation. This study presents that flexible molecular ferries boost CO₂ adsorption, and deciphers how flexible molecular-metal synergy directs the trafficking of CO₂-derived intermediates toward highly efficient CO₂ photoreduction.

Embedding a dielectric layer between as-synthesized graphene nanoribbons (GNRs) and metal surfaces represents a powerful strategy to achieve electronic decoupling, thereby enabling the extraction of these ribbons’ intrinsic electrical properties. Although several reports have documented dielectric intercalation between GNRs and metal substrates, studies on Ag(111) substrates are limited. Here, we demonstrate a semiconducting AgTe monolayer intercalation method to achieve electronic decoupling between as-synthesized GNRs and an Ag(111) substrate. Using low-temperature scanning tunneling microscopy, we directly observed the AgTe intercalation process at the GNR/Ag(111) interface. By combining scanning tunneling spectroscopy and density functional theory calculations, we elucidate the critical role of AgTe monolayer intercalation in reducing the interaction between as-synthesized GNRs and the Ag(111) substrate and observe the near-intrinsic electrical properties of the GNRs. Our findings offer a practical and effective strategy for intercalating AgTe monolayers between carbon-based nanomaterials and Ag(111) substrates, facilitating the unambiguous characterization of the near-intrinsic electronic properties of these materials.

To meet the stringent requirements of next-generation aerospace, electronics, and environmental applications, structural materials must possess intrinsic multi-functionality. However, conventional glass fiber/epoxy (GF/EP) composites, while structurally competent, are hindered by deficiencies such as poor interlaminar toughness, low thermal conductivity, and an inability to interact effectively with electromagnetic microwaves. In this study, we transform GF/EP composites from traditional structural components into advanced structural multifunctional materials by embedding T₃C₂T_x MXene/poly(acrylic acid) (PAA) aerogels (TPA) as integral interlayers. Hybrid composites with tailored architectures, the aligned (GFAM_A) and the random (GFAM_R) TPA/GF/EP laminates, were fabricated using unidirectional and isotropic freeze-casting, respectively. The resulting hybrid composites show significant improvements over baseline GF/EP. The integrated aerogel phase promotes mechanisms of crack deflection and distributed energy dissipation, leading to notable enhancements in interlaminar shear strength (ILSS) and fracture toughness. Critically, the continuous T₃C₂T_x MXene network within the aerogel creates efficient through-thickness thermal conduction pathways and imparts strong microwave absorption properties to the previously electromagnetically transparent composite. Notably, the configuration incorporating aligned aerogels achieves simultaneous increases of approximately 52% in ILSS, 78% in toughness, and 42% in thermal conductivity, along with effective microwave absorption properties, exhibiting a minimum reflection loss of −23.47 dB and a maximum effective bandwidth of 2.70 GHz. This study demonstrates that precision aerogel engineering provides a powerful strategy for upgrading conventional glass fiber composites into advanced multifunctional structural materials.

The polyanionic compound Na₃V₂(PO₄)₂O₂F (NVPOF), featuring a stable three-dimensional framework structure, high theoretical specific capacity, and operating voltage, has been widely studied in recent years. However, its sluggish Na⁺ diffusion kinetics and low electronic conductivity restrict the industrialization process of this material. Based on this, this study proposes a dual regulation strategy of carbon coating and heat treatment temperature regulation, revealing the synergistic mechanism of the two on the crystallinity and electrochemical performance of NVPOF. The NVPOF@C-400 and NVPOF@C-600 are successfully synthesized via in-situ dopamine hydrochloride coating coupled with heat treatments at 400 and 600 °C. Results show that carbon coating treatment at 600 °C remarkably enhances the material’s crystallinity and simultaneously increases its electronic conductivity by three orders of magnitude via the carbon layer’s conductive network. More crucially, the ∼4.5 nm carbon coating layer effectively restrains the abnormal growth and secondary crystallization aggregation of NVPOF grains at high temperatures, keeping the particle size uniformly stable at approximately 0.36 µm. This prevents ion transport obstruction due to grain coarsening, shortens the Na⁺ diffusion pathway, and thus achieves a comprehensive improvement in the material’s electrochemical performance. NVPOF@C-600 delivers a high discharge capacity of 102.5 mAh g⁻¹ at 20 C, and retains 96.5% of its capacity even after 10,000 cycles. What is particularly striking is that the NVPOF@C-600//HC full-cell system performs exceptionally well, maintaining an impressive 89.3% capacity retention rate even after 9000 cycles. This study provides critical insights for the practical implementation of high-performance NVPOF cathodes.

Transient energy storage devices represent an emerging class of biodegradable power systems that provide temporary energy for implantable medical electronics before safely degrading in vivo. From early transient primary batteries to contemporary rechargeable batteries integrated with wireless charging systems, these devices have evolved to enable a stable prolonged power supply. Through rational transient design and structural engineering, they achieve desirable electrochemical performance, tunable degradation rates, and mechanical compatibility with soft, irregular, and dynamic biological tissues. This work provides a critical review of state-of-the-art transient energy storage devices, including transient primary batteries, transient secondary batteries, and transient supercapacitors, with emphasis on their electrodes, electrolytes, encapsulation materials, fabrication processes, and applications. We critically analyze material selection strategies, transient design principles, and architecture design for various transient batteries and capacitors. Finally, we discuss existing challenges and outline future directions to guide the clinical translation of biodegradable power solutions for biomedical implants.

As a non-invasive tumor therapy, photothermal therapy (PTT) has garnered considerable attention for its controllability, non-drug resistance and precise tumor ablation. However, its efficacy is often hindered by limited photothermal damage resulting from uncontrollable heat transfer distance and weak immune response caused by insufficient antigen presentation, resulting in tumor metastasis. Herein, a chondroitin sulfate-modified Prussian blue-montmorillonite immunoregulator (PM@CS) is developed to enhance both photothermal ablation and immune response. By integrating the tumor cell adhesion of montmorillonite and Golgi-targeting of CS, PM@CS accumulates on the Golgi apparatus of tumor cells, significantly reducing heat transfer distance compared to Prussian blue alone, thereby enhancing photothermal efficacy. Furthermore, the enhanced photothermal damage can effectively interfere with post-translational modification and secretion of metastasis-associated proteins (the expression of GOLPH3 and GOLM1 reduced by 63.4% and 70.3%, respectively). Besides, PM@CS leads to a 3.3-fold increase in dendritic cell maturation (CD80⁺ and CD86⁺ populations) and promotes the proliferation of antigen-specific CD4⁺ and CD8⁺ T cells, which is related to the immune potentiator property of montmorillonite and facilitates antigen presentation. Notably, the voltage-gated calcium channels (CaV) were upregulated and Ca²⁺ inflow was enhanced after PM@CS treatment, ultimately activating calcium signaling cascades. This is conducive to amplifying cascade immunotherapy, thus synergistically inhibiting primary tumor growth and lung metastasis.

Sutures, as necessary medical devices for postoperative treatment, are no longer merely supportive but are required to have advanced functions to promote repair. Here, we report an absorbable self-powered electrical stimulation suture. The suture is composed entirely of absorbable materials (magnesium, polylactic acid, and polycaprolactone) and can be used in vivo for incision closure and repair. The suture has the capacity to generate spontaneous electrical stimulation in response to body movement, allowing for accelerated tissue reconstruction. An in vivo muscle incision repair model demonstrated that the wound healing rate under treatment with this suture was 1.6 times faster than that of commercial sutures, proving its postoperative therapeutic capability.

P2-Na_0.67Ni_0.33Mn_0.67O₂ is highly expected to serve as a hopeful cathode for sodium-ion batteries, owing to its remarkable energy density and operating voltage. However, the severe phase transition of P2-O2 at high cut-off voltage induces large volume variation, which deteriorates the structure and leads to fast capacity decay. Over the past years, ion doping has been identified as an efficient way to suppress the phase transition, and a lot of attempts show the positive impact. Regrettably, concurrently achieving high capacity and high stability is still difficult work. In this work, we confirm that high capacity and high stability can be realized by precise composition regulation. The designed P2-Na_0.67Ni_0.28Mg_0.03-Fe_0.04Mn_0.55Ti_0.1O₂ maintaining the high electrochemical active element shows well suppressed phase transition, which contributes to outstanding structural stability and fast charge transfer kinetics. As a result, it shows a high specific capacity of 143.5 mAh g⁻¹ at 0.1 C, and operates with a long lifespan of 1000 cycles. This work demonstrates a new idea for concurrently realizing high capacity and stable cathode material by rationally structure design.

The high-value utilization of industrial wastes is critically important for environmental protection and the sustainable development of society. In this work, amorphous NaFeP₂O₇ (named NFPO) and NaFeP₂O₇/rGO (named NFPO/rGO) composite are synthesized via a selective chemical precipitation approach, utilizing the industrial jarosite residue as the iron source. The sodium storage performance and mechanism of this amorphous NFPO/rGO composite as a novel cathode material for sodium-ion batteries (SIBs) are explored for the first time. The as-synthesized amorphous NFPO/rGO composite exhibits outstanding long-term cycling performance of 79.1 mAh g⁻¹ after 1000 cycles at 0.1 A g⁻¹, while the crystalline NFPO/rGO composite does not work. Galvanostatic intermittent titration technique and in-situ electrochemical impedance spectroscopy analysis demonstrate that the amorphous NFPO/rGO composite has high Na⁺ diffusivity and fast kinetics. In-situ X-ray diffraction analysis reveals the structure change from amorphous NaFeP₂O₇ to triclinic Na₂FeP₂O₇ during the first discharge process and then evolves to a highly disordered structure in the subsequent charge/discharge cycles. The present work not only provides an avenue for the high-value utilization of jarosite residue but also offers theoretical guidance for the structural design and development of NaFeP₂O₇-based cathode materials for SIBs.