Solid-state lithium metal batteries are considered to be the next generation of energy storage systems due to the high energy density brought by the use of metal lithium anode and the safety features brought by the use of solid electrolytes (SEs). Unfortunately, besides the safety features, using SEs brings issues of interfacial contact of lithium anode and electrolytes. Recently, to realize the application of solid-state lithium metal batteries, significant achievements have been made in the interface engineering of solid-state batteries, and various new strategies have been proposed. In this review, from the interface failure perspective of solid-state lithium metal batteries, we summarize failure mechanisms in terms of poor physical contact, weak chemical/electrochemical stability, continuing contact degradation, and uncontrollable lithium deposition. We then focused on the latest strategies for solving interface issues, including advancing in improving the physical solid–solid contact, increasing the electrochemical/chemical stability, restraining continuing contact degradation, and controlling homogeneous lithium deposition. The ultimate and paramount future developing directions of solidstate lithium metal battery interface engineering are proposed.
Traditionally, it is relatively easy to process metal materials and polymers (plastics), while ceramic and inorganic semiconductor materials are hard to process, due to their intrinsic brittleness caused by directional covalent bonds or the strong electrostatic interactions among ionic species. The brittleness of semiconductor materials, which may degrade their functional performance and cause catastrophic failures, has excluded them from many application scenarios. The exploration on room-temperature ductile semiconductors has been a long pursuit of mankind for fabricating deformable and more robust electronics. Guided by this goal, researchers have already found that the plasticity of brittle semiconductors can be enhanced by size effects, which include fewer pre-existing micro-cracks and increased dislocation activity, charge characteristics, and defect density. It has also been explored that a few quasi-layered/van der Waals semiconductors can have exceptional roomtemperature metal-like plasticity, enabled by the relatively weak interlayer bonding and easy interlayer gliding. More recently, intrinsic exceptional plasticity has been found in a group of all-inorganic perovskites (CsPbX3, X = Cl, Br and I), which can be morphed into distinct morphologies through multislip at room temperature, without affecting their functional properties and bandgap energy. Based on the above research status, in this review, we will discuss and present the relevant works on the plasticity found in inorganic semiconductors and the proposed deformation mechanisms. The potential applications and bottlenecks of plastic semiconductors in manufacturing nextgeneration deformable electronic/optoelectronic devices and energy systems will also be discussed.
The significant advancement of high-power densification and miniaturization in modern electronic devices has attracted increasing attention to effective thermal management. The primary objective of thermal management is to transfer excess heat from electronics to the outside environment through the use of thermal conductive materials. The anisotropic thermally conductive films (TCFs) based on two-dimensional (2D) nanomaterials exhibit outstanding controlled heat transfer capability, which effectively removes hotspots along the in-plane direction and provides thermal insulation along the cross-plane direction. However, a comprehensive review of anisotropic TCFs is rarely reported. Herein, we first discuss the intrinsic anisotropic thermal conductivity of 2D nanomaterials for preparing TCFs. Then, the preparation methods and anisotropic thermal conductivity of TCFs have been summarized and discussed. Furthermore, we conclude with the practical applications of TCFs for anisotropy thermal management. Finally, a conclusion of the challenges and outlook of TCFs is provided to promote their development in future scientific research.
Precise recognition and specific interactions between biomolecules are key prerequisites for ensuring the performance of all actives within living organisms. The convergence of biomolecular recognition systems into synthetic materials could endow the materials with high specificity and biological sensitivity; this, in turn, enables precise drug release, monitoring or detection of important biomolecules, and cell manipulation through targeted capture or release of specific biomolecules. Meanwhile, from the perspective of materials science, the application of conventional polymers in practical biological systems poses several challenges, such as low responsiveness and sensitivity, inadequate targetability, insufficient anti-interference capacities, and unsatisfactory biocompatibility. These problems could be partly attributed to the polymers' weak discrimination abilities toward target biomolecules in the presence of interfering substances with high abundance. In particular, the proposition of “precision medicine” project raises higher demands for the design of biomaterials in terms of their precision and targetability. Therefore, there is an urgent demand for the development of new-generation biomaterials with precise recognition and sensitive responsiveness comparable to biomacromolecules. This promotes a new research direction of biomolecule-responsive polymers and their diverse applications. This review focuses on the origin and construction of biomolecule-responsive polymers, as well as their attractive applications in drug delivery systems, bio-detection, bio-sensing, separation, and enrichment, as well as regulating cell adhesion.
The brittleness of ceramics restricts their engineering application. Prestressing is promising to solve the problem, yet still lacks enough attention and extensive investigation. This work proposes the idea of macro-scale and microscale prestressed ceramics: to form compressive prestress in macro- or microscale range in the ceramics by designed additional force, which offsets the fracture stress at the crack tips, then enhances the strength of ceramics. The macro-scale prestressed ceramic has a designed long-range ordering stress distribution in a large scale, similar to the reinforced concrete and tempered glass. The micro-scale ceramic has a designed short-range ordered stress distribution, similar to that in the natural biomaterials. Strategies constructing the macro-scale and micro-scale prestressed ceramics are planned. Future research interests and challenges are prospected for developing the mechanical properties of ceramics.
Compositions and morphologies of Pt-based electrocatalysts have great impact on the electrocatalytic activity and stability of oxygen reduction reaction (ORR). Herein, we report a novel design of one-dimensional (1D) Pt–Pd dendritic nanotubular heterostructures (DTHs) by controlling the degree of Pt2+-Pt reduction reaction and Pd-Pt galvanic replacement reaction with uniform Pd nanowires as sacrificial templates. The obtained Pt–Pd bimetallic DTHs catalyst exhibited uniform and dense Pt dendritic nanobranches on the surface of 1D hollow Pt–Pd alloy nanotubes, possessing superior catalytic activity for ORR compared to state-of-the-art commercial Pt/C catalysts. Typically, the Pt4Pd DTHs catalyst showed efficient mass activity (MA, 1.05 A mgPt−1) and specific activity (SA, 1.25 mA cmPt−2) at 0.9 V (vs. RHE), and the catalyst exhibited high stability with 90.4% MA retention after 20 000 potential cycles. The Pt–Pd bimetallic DTHs configuration combines the advantages of 1D hollow nanostructures and dense Pt dendritic nanobranches, which results in rich electrochemical active surface sites, fast charge transport, and multiple dendritic anchoring points contact on carbon support, thus boosting its catalytic activity and stability towards electrocatalysis.
Fluorene-containing branched poly(aryl-ether-ketone) (BFPAEK) with terminal hydroxyl groups is synthesized by random copolycondensation reaction; then, the CF@BFPAEK/PEEK laminated composite is prepared by the “powder impregnation-high temperature compression molding” method with poly(ether-ether-ketone) (PEEK) as the matrix and BFPAEK-modified carbon fiber (CF@BFPAEK) as the reinforcement. When the content of branched units in BFPAEK is 10% and the coating amount of BFPAEK on the carbon fiber (CF) surface is 3 wt%, the CF@BFPAEK/PEEK laminated composite has outstanding mechanical properties, with an interlaminar shear strength (ILSS) of 57.3 MPa and flexural strength of 589.4 MPa, which are 80.2% and 44.3% higher than those of the pure CF/PEEK laminated composite (31.8 and 408.4 MPa), respectively. After 288 h of hydrothermal aging and high/low-temperature alternating aging, the corresponding retention rate of ILSS and flexural strength are respectively 87.9% and 84.7%, higher than those of pure CF/PEEK laminated composites (74.5% and 70.4%). The thermal conductivity coefficient and temperature for 5% weight loss of CF@BFPAEK/ PEEK laminated composite are 1.85W m-1 K-1 and 538.0°C, respectively.
TiO2 has attracted much attention in the field of photocatalytic degradation of antibiotics due to its good photostability, nontoxicity, and low cost. However, the rapid recombination of photogenerated carriers limits the further improvement of its photocatalytic activity. Here, a facile microwave-assisted hydrothermal method has been developed to prepare Pt clusters decorated TiO2 nanoparticles. Pt clusters ranging in size from 1 to 2 nm are uniformly distributed across the surface of the TiO2 matrix. A pronounced charge transfer phenomenon is discernible between the Pt and TiO2 components. It is revealed that the charge transfer enables faster transfer and separation of photogenerated electrons and holes, which are beneficial for the improvement of photocatalytic degradation of both ofloxacin and levofloxacin. The degradation capability can be attributed to the efficient generation of •OH or •O2− species within the solution. The parallel adsorption model of TiO2 on antibiotic molecules is verified, and the degradation reaction pathway has been elucidated. This work provides a facile method for optimizing the performance of TiO2 photocatalysts, which can be extended to other oxide photocatalysts.