Anion-Exchange Strategy for Ru/RuO-Embedded N/S--Doped Porous Carbon Composites for Electrochemical Nitrogen Fixation.

Ionic porous polymers have been widely utilized efficiently to anchor various metal atoms for the preparation of metal-embedded heteroatom-doped porous carbon composites as the active materials for electrocatalytic applications. However, the rational design of the heteroatom and metal elements in HPC-based composites remains a significant challenge, due to the tendency of the aggregation of metal nanoparticles during pyrolysis. In this study, a nitrogen (N)- and sulfur (S)-enriched ionic covalent organic framework (COF) incorporating viologen and thieno[3,4-b] thiophene (TbT) was constructed via Zincke-type polycondensation.

Dynamic Liquid Crystal Elastomers for Body Heat- and Sunlight- Driven Self-Sustaining Motion via Material-Structure Synergy.

Self-sustained actuators powered by natural, low-energy sources based on liquid crystal elastomers (LCEs) are attractive as they offer high safety, abundant energy availability, and practicality in applications. However, achieving stable self-sustaining motion with low-energy sources requires high actuation strain rates within a narrow temperature range near ambient conditions - a great challenge as LCEs with low nematic-to-isotropic transition temperatures (T) generally exhibit reduced actuation strain and strain rates. To address this, we synthesized a carbon nanotube-doped LCE with a low T and reversible Diels-Alder crosslinks, termed DALCE, and readily (re)fabricated it into specific structures (e.

Dynamic encryption systems enabled by novel α-cyanostilbene-based AIE-active liquid crystalline polymers with self-assembling saccharide units.

This study presents a new side-chain liquid crystalline polymer (SCLLCP) combining α-cyanostilbene and saccharide units. Designed to boost aggregation-induced emission (AIE), the polymer shows tunable optical properties, making it suitable for information encryption and decryption. It displays strong fluorescence in aggregated states and stable liquid crystalline phases, highlighting its potential for secure data transmission.

Dynamic AIE crosslinks in liquid crystal networks: visualizing for actuation-guiding, re-bonding for actuation-altering.

Covalent adaptable liquid crystal networks (CALCNs) are highly potential actuating materials due to their actuation properties and shape reprogrammability. Given the importance of network crosslinking state in a CALCN actuator, we sought an all-in-one strategy to probe and visualize its dynamic network while ensuring actuation and reprogramming. Here, tetraphenylethylene derivatives were incorporated into liquid crystal networks via the Diels-Alder (DA) reaction, acting simultaneously as reversible crosslinkers and aggregation-induced emission (AIE) fluorescent probes.

Electrically driven liquid crystal network actuators.

Soft actuators based on liquid crystal networks (LCNs) have aroused great scientific interest for use as stimuli-controlled shape-changing and moving components for robotic devices due to their fast, large, programmable and solvent-free actuation responses. Recently, various LCN actuators have been implemented in soft robotics using stimulus sources such as heat, light, humidity and chemical reactions. Among them, electrically driven LCN actuators allow easy modulation and programming of the input electrical signals (amplitude, phase, and frequency) as well as stimulation throughout the volume, rendering them promising actuators for practical applications.

Desynchronized liquid crystalline network actuators with deformation reversal capability.

Liquid crystalline network (LCN) actuator normally deforms upon thermally or optically induced order-disorder phase transition, switching once between two shapes (shape 1 in LC phase and shape 2 in isotropic state) for each stimulation on/off cycle. Herein, we report an LCN actuator that deforms from shape 1 to shape 2 and then reverses the deformation direction to form shape 3 on heating or under light only, thus completing the shape switch twice for one stimulation on/off cycle. The deformation reversal capability is obtained with a monolithic LCN actuator whose two sides are made to start deforming at different temperatures and exerting different reversible strains, by means of asymmetrical crosslinking and/or asymmetrical stretching.

Optimizing the structural design of a nanocomposite catalyst layer for PEM fuel cells for improving mass-specific power density.

For the purpose of redesigning a PEM fuel cell with ultralow Pt loading, this review comprehensively summarizes and comments on recent important findings on ultrathin catalyst layer structures. We introduce recent advances in electrocatalyst research and development (R&D), highlighting the urgency of ultralow Pt loading in the total design of PEM fuel cells. Following that, the reason for a thinner and more ordered electrode structure is presented for the next generation of PEM fuel cells.

Recent advances in catalysts, electrolytes and electrode engineering for the nitrogen reduction reaction under ambient conditions.

With the conventional Haber-Bosch NH3 synthesis in industry requiring harsh pressures and high temperatures, artificial N2 fixation has been long sought after. The electrochemical nitrogen reduction reaction (NRR) could offer a solution by allowing NH3 production under ambient conditions. In this review, important recent findings on theoretical calculations and experimental exploration on the NRR at room temperature are systematically reviewed.

Facile stabilization of a cyclodextrin metal-organic framework under humid environment hydrogen sulfide treatment.

Increasing resistance to humid environments is a major challenge for the application of γ-CD-K-MOF (a green MOF) in real-world utilisation. γ-CD-K-MOF-HS with enhanced moisture tolerance was obtained by simply treating MOF with HS gas. XPS, Raman and TGA characterizations indicated that the HS molecules coordinated with the metal centers in the framework.

Tough Self-Healing Elastomers Based on the Host-Guest Interaction of Polycyclodextrin.

Inspired by animal muscles, we developed a kind of tough elastomers combining high strength and high stretchability with autonomous self-healing capability. A key structural feature is the construction of a double network (DN) connected by the hydrogen bond and host-guest interactions. The first network is the classic elastomer polyacrylate matrix cross-linked by strong hydrogen bonding.

Leeches-Inspired Hydrogel-Elastomer Integration Materials.

Inspired by the functions of leeches, for the first time homogeneous materials integrating hydrogels and elastomers were achieved by free radical polymerization. 2-Methoxyethyl acrylate (MEA) was used as elastomer monomer and Pluronics functionalized with vinyl groups acted as cross-linkers to impart the hydrogel property to the materials. The resulting Pluronic/PMEA gels possess a swelling ratio of about 210% and good water-retaining ability.

Formation mechanism of TiO2 nanotubes and their applications in photoelectrochemical water splitting and supercapacitors.

Structural observations of the transition of TiO2 nanopores into nanotubes by increasing the OH(-) concentration in the electrolyte challenge the validity of existing formation mechanisms of anodic TiO2 nanotubes. In this study, dehydration of titanium hydroxide in the cell wall is proposed as the mechanism that leads to the separation of neighboring nanotubes. Based on this understanding, bamboo-type TiO2 nanotubes with large surface area and excellent interconnectivity are achieved by cycling high and low applied potentials.

Lithium oxides precipitation in nonaqueous Li-air batteries.

Lithium-air/oxygen battery is a rising star in the field of electrochemical energy storage as a promising alternative to lithium ion batteries. Nevertheless, this alluring system is still at its infant stage, and the breakthrough of lithium-air batteries into the energy market is currently constrained by a combination of scientific and technical challenges. Targeting at the air electrode in nonaqueous lithium-air batteries, this review attempts to summarize the knowledge about the fundamentals related to lithium oxides precipitation, which has been one of the vital and attractive aspects of the research communities of science and technology.

Membranes in lithium ion batteries.

Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries.

Graphene-based electrochemical energy conversion and storage: fuel cells, supercapacitors and lithium ion batteries.

Graphene has attracted extensive research interest due to its strictly 2-dimensional (2D) structure, which results in its unique electronic, thermal, mechanical, and chemical properties and potential technical applications. These remarkable characteristics of graphene, along with the inherent benefits of a carbon material, make it a promising candidate for application in electrochemical energy devices. This article reviews the methods of graphene preparation, introduces the unique electrochemical behavior of graphene, and summarizes the recent research and development on graphene-based fuel cells, supercapacitors and lithium ion batteries.