Science China Materials最新文献

Bismuth oxyhalide (BiOCl) holds promising potential as the anode for sodium-ion batteries (SIBs) due to its high theoretical capacity and unique layered structure. However, its practical applications are hindered by challenges such as large volume variations during cycling, the ambiguous Na⁺-storage mechanism, and complex synthesis methods. Here, we present a facile and scalable strategy to fabricate a high-performance BiOCl nanosheets anode for SIBs. Through comprehensive in-situ and ex-situ microscopic characterizations and electrochemical analysis, we reveal that the sodiation/desodiation process of the BiOCl nanosheets anode leads to the formation of metallic Bi and Na₃OCl. The metallic Bi acts as an active material for Na⁺ storage in subsequent cycles, while the formed Na₃OCl enhances the stability of the solid-electrolyte interphase (SEI) layer and facilitates Na⁺ transport. Additionally, the metallic Bi gradually transforms into a nanoporous structure during cycling, improving Na⁺ transport and mitigating volume variations. As a result, the BiOCl nanosheets anode exhibits outstanding electrochemical performance, with impressive rate capability and cycling stability. Furthermore, full cells paired with the Na₃V₂(PO₄)₃ (NVP) cathode and pre-cycled BiOCl nanosheets anode also demonstrate a superior rate and cycling performance. This work offers valuable insight into the development of high-performance anodes for advanced SIBs.

Rationally modulating the adsorption configuration of the key *CO intermediate could facilitate carbon-carbon (C-C) coupling to generate multi-carbon products in the electrochemical CO₂ reduction reaction. In this work, theoretical calculations reveal that C-C coupling via atop-adsorbed *CHO and hollow-adsorbed *CO over Cu sites is an energetically favorable pathway. As a proof of concept, a tandem trimetallic AuAgCu heterojunction (Au@Ag/Cu) was prepared, where the atop-adsorbed *CO over Au@Ag sites could migrate to Cu sites with hollow adsorption configuration, and then the asymmetric C-C coupling via transferred hollow-adsorbed *CO and existed atop-adsorbed *CHO over Cu sites facilitates the formation of the ethanol product, exhibiting a maximum Faraday efficiency of 65.9% at a low potential of −0.3 V vs. reverse hydrogen electrode. Our work provides new insights into the intrinsic understanding of tandem catalysis by regulating adsorption configuration of the intermediate products.

The development of high-performance near-infrared (NIR) absorbing electron acceptors is a major challenge in achieving high short-circuit current density (J_SC) to increase power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, three new multi-heteroatomized Y-series acceptors (bi-asy-Y-Br, bi-asy-Y-FBr, and bi-asy-Y-FBrF) were developed by combining dual-asymmetric selenium-fused core and brominated end-groups with different numbers of fluorine substitutions. With gradually increasing fluorination, three acceptors exhibit red-shift absorption. Among them, bi-asy-Y-FBrF presents planar molecular geometry, the maximum average electrostatic potential, and the minimum molecular dipole moment, which are conducive to intramolecular packing and charge transport. Moreover, D18:bi-asy-Y-FBrF active layer presents higher crystallinity, more suitable phase separation, and reduced charge recombination compared to D18:bi-asy-Y-Br and D18:bi-asy-Y-FBr blends. Consequently, among theses binary OSCs, D18:bi-asy-Y-FBrF device achieves a higher PCE of 15.74% with an enhanced J_SC of 26.28 mA cm⁻², while D18:bi-asy-Y-Br device obtains a moderate PCE of 15.04% with the highest open-circuit voltage (V_OC) of 0.926 V. Inspired by its high V_OC and complementary absorption with NIR-absorbing BTP-eC9 as acceptor, bi-asy-Y-Br is introduced into binary D18:BTP-eC9 to construct ternary OSCs, achieving a further boosted PCE of 19.12%, which is among the top values for the reported green solvent processed OSCs.

As future soft robotic devices necessitate a level of complexity surpassing current standards, a new design approach is needed that integrates multiple systems necessary to synchronize the motions of soft actuators and the response of signals, thereby enhancing the intelligence of flexible devices. Herein, we propose a liquid crystal elastomer unit cell-based platform that organizes the cells in a group to create expandable functions. One unit cell behaves like a flexible module that can expand biaxially into a specific, stable, and controllable pattern. Collaborating the unit cells in different manners results in an adaptable soft grasper, a half-adder for information processing, and a tunable phononic bandgap. This implies a high level of reconfigurability and scalability in both structures and functions by elegantly reassembling the unit cells. This design strategy has the potential to integrate multiple functions that traditional soft actuators cannot accommodate, providing a platform for developing intelligent soft robotics.

Zinc powder-based anodes encounter significant challenges, including severe side-reactions and non-uniform Zn plating-stripping processes. These issues lead to poor reversibility and low zinc utilization, which substantially impede their practical applications. Herein, we fabricated a multifunctional carbonyl-containing zinc metharcylate (ZMA) layer on the surface of three-dimensional (3D) zinc powder anode through in-situ modification. The ZMA layer with high electronegativity and highly nucleophilic carbonyl group assists the de-solvation process, which is conducive to the Zn²⁺ transport and homogenization of the ionic flux. In addition, the hydrophobic carbon chains in ZMA work as a protective layer to reduce the Zn powder direct contact with free-water and significantly improving side-reactions resistance. Finally, through the synergistic effect of ZMA and 3D Zn structure, the prepared electrode could cycle stably at 20 mA cm⁻²/20 mAh cm⁻² for 1153 h (depth of discharge: 38.10%). The stable 3D Zn-MnO₂ battery with a high capacity retention (84.2% over 500 cycles) is also demonstrated.

Zinc and its alloys provide a scalable alternative to the list of biodegradable metals due to its moderate degradation rates and biocompatible degradation products. However, one of the challenges impeding their clinical applications is the uncontrollable and unstable interfacial reactions between zinc implants and the corrosive media. In this study, we report a facile synthesis of metal–organic framework (MOF) nanocrystal coating with tunable thickness on the high-strength Zn-0.8Li alloy matrix for controlled corrosion. The as-obtained dense and uniform MOF nanocrystals form a strong connection with the zinc matrix via coordination bond so as to maintain the mechanical properties, and meantime provide highly rough surfaces exhibiting tunable wettability. The varied MOF coating thus regulate the interface structure between the zinc matrix and corrosive media to control the degradation behavior. Excellent antibacterial activity and biocompatibility are also achieved because of the unique topology morphologies, surface superhydrophilicity, as well as the dynamic Zn²⁺ release. This study sheds valuable lights on the design of MOF-functionalized metal implants for practical use and also triggers extensive applications of MOF in biomaterials.

Atherosclerosis remains a major cause of morbidity and mortality worldwide. Intraplaque neovascularization critically promotes atherosclerotic progression and instability. Vascular endothelial growth factor A (VEGFA) stimulates aberrant microvessel growth in plaques by inducing endothelial cell proliferation and migration. Pigment epithelium-derived factor (PEDF) potently inhibits VEGFA-dependent neovascularization. This study introduces a thermosensitive hydrogel (PFSgel) developed from poloxamer 407 (F127) and sodium alginate (SA) to deliver PEDF locally to atherosclerotic lesions. The PFSgel demonstrated a suitable liquid-solid transition at body temperature (37°C), then forming a stable 3D network structure after SA gelling with the Ca²⁺ in the physiological environment which contributed to the character of controlled release. Rheological analysis confirmed its phase transition temperature of 28.7°C and notable self-healing properties, making it ideal for dynamic vascular environments. In vitro experiments showed that PFSgel could suppress VEGFA-induced endothelial cells’ proliferation and migration through modulation of CD31 and MMP-2/MMP-9 signaling. Notably, in vivo degradation test validated the controlled release pattern of PFSgel. In Apoe-deficient atherosclerotic mice, ultrasound-guided PFSgel injection onto the abdominal aorta enabled gradual in situ release of encapsulated PEDF. This effectively reduced plaque burden, neovascularization, and luminal stenosis, even with exogenous VEGFA administration. Histological analyses confirmed reduced lipid deposition, plaque area, and neovascularization within plaques. Overall, this novel in situ-forming PEDF delivery platform enables targeted suppression of pathological neovascularization via CD31 and MMP-2/MMP-9 pathways, representing a promising approach to stabilize high-risk plaques by intervening against VEGFA-dependent neovascularization.

Electrical stimulation therapy has excellent potential for wound healing and tissue regeneration. However, conventional approaches often require external power sources and implantable electrodes, which can limit their practical applications. Herein, we report the development of an ultrasound-mediated powered wound healing device (LH-TENG) that employs skin-adhesive AgC@L-g-PAM/HPC hydrogel as electrodes instead of traditional ones. Under ultrasound excitation, the LH-TENG can firmly adhere to tissue surfaces and generate a uniform electric field around the wound area, promoting cell migration, proliferation, and accelerating healing. Notably, the device exhibits antibacterial properties, making it promising for treating infected chronic wounds. Due to its wireless power supply, simple structure, and excellent biocompatibility, this ultrasound-mediated wound healing device has the potential and advantages of developing implantable therapy devices for treating infected chronic wounds.

Homogeneous redox mediation is efficient in alleviating the shuttling effect and slow redox kinetics of lithium polysulfides in lithium-sulfur batteries. However, their perfect performance is not fulfilled owning to the fact that the multi-step transformation of lithium polysulfides requests the multifunctional active positions for the tandem catalysis. Based on the redox comediation principles, a promoter of mixing organodiselenide and organoditelluride (mixed-Se/Te) was raised to induce tandem catalysis and boost the effective electrochemical conversion of lithium polysulfides. More specifically, diphenyl diselenide facilitated the liquid-liquid and solid-liquid transformation between lithium polysulfides and sulfur, while diphenyl ditelluride improved the solid-liquid transformation concerning lithium sulfide deposition. Consequently, even under high sulfur loading of 6.5 mg cm⁻² and low electrolyte/sulfur ratio of 5.88 µL mg⁻¹, the 10 mM low concentration mixed-Se/Te promoter offered a high discharge capacity of 6.6 mAh cm⁻² and high rate performance of 4.1 mAh cm⁻² at 0.5 C. Moreover, the assembled 1.5 Ah-level lithium-sulfur pouch cells provide an energy density of 332 Wh kg⁻¹ at 0.05 C and good cycling stability. Our research demonstrates the applicability of propelling continuous sulfur conversion reactions with detached active positions and is anticipated to stimulate deep molecular design of kinetic promoter to targeted energy-associated redox reactions.

Phase transformation of two-dimensional (2D) nanomaterials can lead to significant changes in electronic and optical properties, which enables the development of novel applications. Effective strategies for phase engineering of 2D nanomaterials have drawn considerable attention in recent years. This review focuses on the state-of-the-art progress in the phase transformation of 2D nanomaterials and their catalytic applications. First, the basic concepts of phase transformation and the outstanding electronic and optical properties induced by phase transformation are briefly introduced. Second, different strategies for achieving phase transformation are discussed in detail and classified into several types based on their characteristics, including (i) doping, (ii) external fields, (iii) optical irradiation, (iv) strain effect, (v) high-energy particle excitation, and (vi) thermal post-processing. The applications of 2D nanomaterials in catalysis based on phase transformation have also been discussed. Finally, a summary of the technical challenges to phase control in 2D nanomaterials and potential opportunities for developing novel applications is presented.