Confined Growth of Highly Ordered Metal Atomic Arrays for Seawater Oxidation.

Metal atom catalysts have been among the most important research objects due to their specific physical and chemical properties. However, precise control of the anchoring of metal atoms is still challenging to achieve. Cobalt and iridium atomic arrays formed sequentially ordered stable arrays in graphdiyne (GDY) triangular cavities depending on their intrinsic chemical properties and interactions. The success of this method was attributed to multifunctional integration of GDY, enabling selective growth from one to several atoms and various atomic densities. The bimetallic atom arrays show several advantages resulting from reducibility of acetylene bonds, space limiting effect, incomplete charge transfer between GDY and metal atoms, and sp-C hybridized triple bond skeleton. This well-designed system exhibits unprecedented oxygen evolution reaction (OER) performance with a mass activity of 2.6 A mgcat.-1 at a low overpotential of 300 mV, which is 216.6 times higher than the state-of-the-art IrO2 catalyst, and long-term stability.

HsGDY 3D Framework-Encapsulated Cu2O Quantum Dots for High-Efficiency Energy Storage.

Nanostructured electrode materials become a vital component for future electrode materials because of their short electron and ion transport distances for fast charge and discharge processes and sufficient space between particles for volume expansion. So, achieving a smaller size of the nanomaterial with stable structure and high electrode performance is always the pursuit. Herein, the hybrid electrode material system hydrogen-substituted graphdiyne (HsGDY)/Cu2O-quantum dots (QDs) composed of an active carbon substrate and vibrant metal oxide QD load was established by HsGDY and cuprous oxide. The HsGDY frame with conjugated structure not only delivers impressive capacity by a self-exchange mechanism but also characterizes a matrix to forge strong connections with numerous active Cu2O-QDs for the prevention of aggregation, leading to a homogeneous storage and transport of charge in a bulk material of crisscross structural pores. QD-based electrode materials would exhibit desired capacities by their large surface area, abundant active surface atoms, and the short diffusion pathway. The hybrid system of HsGDY/Cu2O-QDs delivers an ultrahigh capacity of 1230 mA h g-1 with loading density reaching up to 1 mg cm-2. In the meantime, the electrode exhibits a long cycle stability of over 8000 cycles. The synergistic effect endows the hybrid system electrode with an approximately theoretical energy density, suggesting the great potential of such carbon/QD hybrid material system applied for high-performance batteries.

Direct solar energy conversion on zinc-air battery.

A concept of solar energy convertible zinc-air battery (SZAB) is demonstrated through rational design of an electrode coupled with multifunction. The multifunctional electrode is fabricated using nitrogen-substituted graphdiyne (N-GDY) with large π-conjugated carbonous network, which can work as photoresponsive bifunctional electrocatalyst, enabling a sunlight-promoted process through efficient injection of photoelectrons into the conduction band of N-GDY. SZAB enables direct conversion and storage of solar energy during the charging process. Such a battery exhibits a lowered charge voltage under illumination, corresponding to a high energy efficiency of 90.4% and electric energy saving of 30.3%. The battery can display a power conversion efficiency as high as 1.02%. Density functional theory calculations reveal that the photopromoted oxygen evolution reaction kinetics originates from the transition from the alkyne bonds to double bonds caused by the transfer of excited electrons, which changes the position of highest occupied molecular orbital and lowest unoccupied molecular orbital, thus greatly promoting the formation of intermediates to the conversion process. Our findings provide conceptual and experimental confirmation that batteries are charged directly from solar energy without the external solar cells, providing a way to manufacture future energy devices.

In situ Construction of Multistage Core-Shell Nanostructure as Bifunctional Catalyst for Ultrastable Zinc-Air Batteries.

Many efforts have been devoted to obtaining excellent cathode catalysts for Zinc air batteries (ZABs), but the inevitable use of binder will damage the catalytic activity and weaken long-term stability, inefficient mass transfer of oxygen is also chargable for the limited activity. Herein, in situ grown hydrogen substituted graphdiyne (HGDY) on carbon paper has been prepared and used as cathode catalyst layer in ZABs. Multiple catalytic sites are firmly combined and end with the boosted bifunctional catalytic activity of oxygen reduction and oxygen evolution. Moreover, the specific surface area, sufficient active sites, multilevel pore nanostructure and robust conductivity are fully exposed to establish efficient catalytic interface and skeleton. Cu/Co nanoparticles are uniformly distributed and warped by HGDY network, which can stably exist during the catalytic process. As a result, a current density of 18.75 mA cm-2 and a Tafel slope of 61.06 mV dec-1 for oxygen reduction and a ultralong operation for more than 2300 h in aqueous ZAB have been achieved, which is beyond many reported bifunctional catalysts in ZAB system.

Alkyne-to-alkene conversion in graphdiyne driving instant reversible deformation of whole carbon film.

The emerging field of soft robotics demands the core actuators and related responsive functional materials with rapid responsiveness and controllable accurate deformation. Here, we developed an alkyne-to-alkene chemical bond conversion way as the driving force to control ultrasensitive and instant reversible deformation of 2D carbon graphdiyne (GDY) film with an asymmetric interface design. The alkyne-to-alkene chemical bond conversion was triggered by acetone through the fast binding and release process. The as-fabricated GDY-based deformation modulator was exhibited to rapidly change shape (within 0.15 seconds) while dipped in an acetone vapor atmosphere and recover to its original form when exposed to air (recovery time < 0.01 seconds), with outstanding properties like large curvature, quick recovery time, excellent stability, and repeatability. It could mimic the movement of mosquito larvae, displaying great promise as micro bionic soft robots. Our results suggest alkyne-to-alkene bond conversion as a unique driving force for developing smart materials for areas like intelligent robotics and bionics.

Synergistic Defect Engineering and Interface Stability of Activated Carbon Nanotubes Enabling Ultralong Lifespan All-Solid-State Lithium-Sulfur Batteries.

Due to the high energy density, high safety, and low cost of sulfur, all-solid-state lithium-sulfur batteries (ASSLSBs) are considered one of the most promising next-generation energy storage devices. Nevertheless, the insufficient interfacial contact between solid electrolytes (SEs) and the active material of sulfur leads to inadequate electronic and ionic conduction, which increases interfacial resistance and capacity decay. In this paper, commercial carbon nanotubes (CNTs) are activated to form porous-CNTs (P-CNTs), which are used as sulfur-bearing matrix, forming S@P-CNTs-based composite cathodes for ASSLSBs. Compared with CNTs, P-CNTs possess a larger specific surface area and more oxygen-containing groups, providing enhanced interfacial contact and stability between S@P-CNTs and Li6PS5Cl SE, which are confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, and density functional theory calculations. Moreover, P-CNTs can form a 3D conductive network in the composite cathodes, facilitating the migration of electrons and the diffusion of ions, as well as improving the utilization of sulfur. As a result, the S@P-CNTs-based ASSLSBs display excellent electrochemical performances, especially rarely reported ultralong lifespan, which deliver a capacity of 1099.2 mA h g-1 at a current density of 1.34 mA cm-2, and remarkably maintain 70.4% of the initial capacity over 1400 cycles.

Advanced Multilayered Electrode with Planar Building Blocks Structure for High-Performance Lithium-Ion Storage.

To achieve the high-performance of lithium-ion battery, the optimization of electrode materials has generally been considered as the one of the important methods. But most of those works pay attention to the new materials preparation or interface modification rather than the structural innovation. Here, an advanced electrode (GDY/BP/GDY-E) with multilevel layered architecture constructed by planar building blocks stacking structure has been designed and fabricated to explore the structure design of the electrode. This new structure is assembled by graphdiyne (GDY) and black phosphorus (BP) in parallel to form a building block (GDY/BP/GDY). The electric fields between the two GDY sides of the planar building block structure contribute to the superior migration dynamics of lithium ions and desirable pseudocapacitance behavior. Meanwhile, the planar stacking structure of GDY/BP/GDY can efficiently inhibit volume expansion of BP and a series of parasitic reactions of electrolytes during the long-term cycling. The advanced GDY/BP/GDY-E exhibits excellent high-rate performance (1418.8 mAh g-1 at 0.1 A g-1 ) and cycling stability (391.7 mAh g-1 after 5000 cycles at 10 A g-1 ). Such structural design of electrode materials shows a new way to develop high-performance electrodes.

Two-Dimensional Carbon Graphdiyne: Advances in Fundamental and Application Research.

Graphdiyne (GDY), a rising star of carbon allotropes, features a two-dimensional all-carbon network with the cohybridization of sp and sp2 carbon atoms and represents a trend and research direction in the development of carbon materials. The sp/sp2-hybridized structure of GDY endows it with numerous advantages and advancements in controlled growth, assembly, and performance tuning, and many studies have shown that GDY has been a key material for innovation and development in the fields of catalysis, energy, photoelectric conversion, mode conversion and transformation of electronic devices, detectors, life sciences, etc. In the past ten years, the fundamental scientific issues related to GDY have been understood, showing differences from traditional carbon materials in controlled growth, chemical and physical properties and mechanisms, and attracting extensive attention from many scientists. GDY has gradually developed into one of the frontiers of chemistry and materials science, and has entered the rapid development period, producing large numbers of fundamental and applied research achievements in the fundamental and applied research of carbon materials. For the exploration of frontier scientific concepts and phenomena in carbon science research, there is great potential to promote progress in the fields of energy, catalysis, intelligent information, optoelectronics, and life sciences. In this review, the growth, self-assembly method, aggregation structure, chemical modification, and doping of GDY are shown, and the theoretical calculation and simulation and fundamental properties of GDY are also fully introduced. In particular, the applications of GDY and its formed aggregates in catalysis, energy storage, photoelectronic, biomedicine, environmental science, life science, detectors, and material separation are introduced.

Boosting Fe Cationic Vacancies with Graphdiyne to Enhance Exceptional Pseudocapacitive Lithium Intercalation.

Modulating the electronic structure of electrode materials at atomic level is the key to controlling electrodes with outstanding rate capability. On the basis of modulating the iron cationic vacancies (IV) and electronic structure of materials, we proposed the method of preparing graphdiyne/ferroferric oxide heterostructure (IV-GDY-FO) as anode materials. The goal is to motivate lithium-ion batteries (LIBs) toward ultra-high capacity, superior cyclic stability, and excellent rate performance. The graphdiyne is used as carriers to disperse Fe3 O4 uniformly without agglomeration and induce high valence of Fe with reducing the energy in the system. The presence of Fe vacancy could regulate the charge distribution around vacancies and adjacent atoms, leading to facilitate electronic transportation, enlarge the lithium-ion diffusion, and decrease Li+ diffusion barriers, and thus displaying significant pseudocapacitive process and advantageous lithium-ion storage. The optimized electrode IV-GDY-FO reveals a capacity of 2084.1 mAh g-1 at 0.1 C, superior cycle stability and rate performance with a high specific capacity of 1057.4 mAh g-1 even at 10 C.

Directly Growing Graphdiyne Nanoarray Cathode to Integrate an Intelligent Solid Mg-Moisture Battery.

A continuous humidity and solar-light dual responsive intelligent solid Mg-moisture battery (SMB) with a graphdiyne nanosheets array was fabricated. The integrated battery works based on a new concept of chemical bond conversion on the surface of the graphdiyne nanosheets array that is grown in situ on a 3D melamine sponge (GDY/MS). The unique structure, excellent catalytic, and semiconductor performance of GDY endows the GDY/MS with some outstanding characteristics on trapping and transferring water molecules, catalyzing HER, and utilizing solar energy, making the GDY/MS a new generation cathode for a high-performance intelligent SMB. The performance of the GDY/MS-based smart SMB (GSMB) can be continuously tuned by humidity and solar-light. The GSMB shows a significant positive correlation between open circuit potential (OCP) and humidity, while the natural band gap of GDY makes it further act as a photoelectrode to capture light and generate photoelectrons. The GSMB can be applied as a self-power humidity monitor with an ultrafast response time of <0.24 s, a recovery time of <0.16 s, and a sensitive (36,600%) respiratory sensing performance. This simple and efficient battery-made strategy represents the future development direction of self-power supply equipment, intelligent electronic devices, and intelligent battery integration.

High energy density primary cathode with a mixed electron/ion interface.

An effective and original strategy described as two-dimensional encapsulation is designed to prepare a high-performance fluorinated carbon cathode composed of a fluorinated carbon/graphdiyne heterostructure (CFx/GDY). The GDY layers of CFx/GDY strengthened the three-dimensional contacts between the CFx particles and additive, achieving outstanding charge transport kinetics and accelerating the lithium-ion diffusion dynamic behavior. The obtained electrodes exhibited a significantly enhanced voltage platform of ∼2.5 V, improved battery rate performance (5C, 621.6 mA h g-1) and energy density with 2039.3 W h kg-1. The excellent storage kinetics can be ascribed to the electronic structure modulation of fluorinated carbon from GDY, and the hierarchical porosity of GDY to create an effective, stable electron transfer and robust ion transportation. Our results demonstrated that two-dimensional GDY encapsulation has enormous potential in improving the performance of lithium primary batteries.

Sp-Hybridized Nitrogen as New Anchoring Sites of Iron Single Atoms to Boost the Oxygen Reduction Reaction.

Carbon supported single-atom catalysts with metal-Nx configuration are considered as one of the most efficient catalysts for the oxygen reduction reaction (ORR). However, most of the metal-Nx active sites are composed by pyridinic N at the defect locations of graphene-like supports. Here, we employ graphdiyne (GDY) as a new carbon substrate to synthesize an iron (Fe) single atom catalyst (Fe-N-GDY), showing excellent catalytic performance. Benefitting from the abundant acetylenic bonds in GDY, sp-N anchored metal atoms are created without forming defects. The sp-N and OH ligands regulate the electronic structure of Fe atoms and optimize the adsorption energy of ORR intermediates on the active sites by reducing the electron local density of Fe atoms, which accelerates the reaction kinetics and promotes the ORR activity of Fe-N-GDY. Furthermore, the practical application of Fe-N-GDY is corroborated by its high power density and long-term performance via assembling a zinc-air battery.

Ultrasensitive Pressure Sensor Sponge Using Liquid Metal Modulated Nitrogen-Doped Graphene Nanosheets.

Wearable pressure sensors are crucial for real-time monitoring of human activities and biomimetic robot status. Here, the ultrasensitive pressure sensor sponge is prepared by a facile method, realizing ultrasensitive pressure sensing for wearable health monitoring. Since the liquid metal in the sponge-skeleton structure under pressure is conducive to adjust the contact area with nitrogen-doped graphene nanosheets and thus facilitates the charge transfer at the interface, such sensors exhibit a fast response and recovery speed with the response/recovery time 0.41/0.12 s and a comprehensive response range with a sensitivity of up to 476 KPa-1. Notably, the liquid metal-based spongy pressure sensor can accurately monitor the human body's pulse, the pressure on the skin, throat swallowing, and other activities in real time, demonstrating a broad application prospect. Those results provide a convenient and low-cost way to fabricate easily perceptible pressure sensors, expanded the application potential of liquid metal-based composites for future electronic skin development.

3D Carbiyne Nanospheres Boosting Excellent Lithium and Sodium Storage Performance.

Reasonable design of electrode materials with specific morphology and structure can efficiently improve the metal ions storage and transmission properties of metal ion batteries. Here the preparation of spirobifluorene-based three-dimensional carbiyne nanosphere (SBFCY-NS) that is composed of spirobifluorene (SBF) and alkyne bonds is reported. Benefiting from the rigid spatial structure of SBF, numerous precursors are coupled through the connection of acetylene bonds, extending to form solid nanospheres. Abundant storage spaces and convenient multi-directional transmission paths for metal ions are available inside the three-dimensional (3D) carbiyne structure. Thus, SBFCY-NS is applied as efficient anode for lithium-ion battery and sodium-ion battery. The good stability of SBFCY-NS-based electrode and its improved Coulombic efficiency can be attributed to the special morphology of nanospheres, which can easily form thin and stable solid electrolyte interface film on the surface. Those results further promote the preparation of spherical carbon-based materials with abundant pores that can be applied in the field of electrodes.

Post-modified Strategies of Graphdiyne for Electrochemical Applications.

The new carbon material graphdiyne (GDY) has been verified to have a great application prospect in electrochemical field. In order to study its properties and expand its scope of application, various experiments including structural control tests are imposed on GDY. Among them, as one of the most commonly used methods to modify the structure, heteroatom doping is favored for its advantages in synthesis methods and the control of mechanical, electrical and even magnetic properties of carbon materials. According to the published studies, the top-down methods of doping heteroatoms for GDY only need cheap raw materials, simple synthetic route and strong controllability, which is conducive to rapid performance breakthroughs in electrochemical applications. This review selects the typical cases in the development of that post-modification method from the application of GDY in the electrochemical field. Here, based on the existed reports, the commonly used non-metal elements (such as nitrogen, sulfur) and metal elements (such as iron) have been introduced to post-modify GDY. Then, a detailed analysis is made for corresponding electrochemical applications, such as energy storage and electrocatalysis. Finally, the challenges and prospects of post-modified GDY in synthesis and electrochemical applications are proposed. This review provides us a useful guidance for the development of high-quality GDY suitable for electrochemical applications.

A Universal Fe/N Incorporated Graphdiyne for Printing Flexible Ferromagnetic Semiconducting Electronics.

The vigorous development of two-dimensional materials puts forward higher requirements for more effective modulation of physical properties. Here, we utilize simple treatments for the emerging graphdiyne (GDY) materials to achieve dual control of magnetic and electrical properties through Fe/N codoping. The as-prepared Fe-N-GDY is confirmed as a highly conductive ferromagnetic semiconductor. The Curie temperature close to 205 K endows the materials promising application prospects in spin-related devices. Benefiting from uniform Fe/N comodification and performance optimization, such material could be used as carbon-based conductive ink for printed devices, such as a printed field-effect transistor (FET), which achieves a high mobility of 215 cm2 V-1 s-1. Even when printing Fe-N-GDY ink to assemble flexible FETs with an ionic liquid gate, the excellent transfer characteristics can be maintained and demonstrate stability with temperature. Those results provide a facile way to modulate GDY's properties and promote its application potential in large-area, multifunctional integrated electronic devices, including wearable devices.

Induced Ferromagnetic Order of Graphdiyne Semiconductors by Introducing a Heteroatom.

To date, the realization of ferromagnetism in two-dimensional carbon semiconductors containing only sp electrons has remained a challenge for spintronics. Here, we utilize the atomic-level functionalization strategy to obtain three carbon matrix materials by accurately introducing different light elements (H, F, Cl) into graphdiyne's benzene ring. Their magnetic and conductive characteristics are thoroughly clarified via physical property measurements and DFT calculations. All of these carbon matrix materials retain their excellent intrinsic semiconductor properties. In particular, compared with the paramagnetism of HsGDY and ClsGDY, a robust ferromagnetic ordering as well as high mobility of up to 320 cm2 V-1 s-1 was observed in FsGDY, successfully realizing a ferromagnetic semiconductor. Through theory calculations, this unique ferromagnetic coupling can be attributed to the most striking charge transfer between carbon and fluorine atoms, demonstrating the advantages of controllable fabrication. These results not only reveal the important role of atomic-scale doping/substitution in optimizing graphdiyne material but also create new possibilities for manipulating spins and charges in 2D carbon materials.

One-Step Preparation of Highly Durable Superhydrophobic Carbon Nanothorn Arrays.

This study proposes a one-step method for growing superhydrophobic carbon nanothorn arrays (NTAs) directly on various substrates. The fabricated carbon material (named methyl-substituted graphdiyne (MGDY)) comprises sp and sp2 carbons in a conjugated-backbone form, as well as methyl groups introduced into the framework as hydrophobic-enhanced functional groups. MGDY NTAs exhibit excellent hydrophobicity (contact angle ≥152°), substantial long-period hydrophobic durability (the contact angle decreased by only 3.2% over 800 days), and acid/alkali tolerance. Owing to the enhanced durability and specific stability of carbon, a superhydrophobic interface can easily be constructed using MGDY NTAs, which can be applied to achieve successful long-term metal-corrosion protection and efficient oil-water separation.

Tuning the Properties of Graphdiyne by Introducing Electron-Withdrawing/Donating Groups.

The properties of graphdiyne (GDY), such as energy gap, morphology, and affinity to alkali metals, can be adjusted by including electron-withdrawing/donating groups. The push-pull electron ability and size differences of groups play a key role on the partial property adjusting of GDY derivatives MeGDY, HGDY, and CNGDY. Cyano groups (electron-withdrawing) and methyl groups (electron-donating) decrease the band gap and increase the conductivity of the GDY network. The cyano and methyl groups affects the aggregation of GDY, providing a higher number of micropores and specific surface area. These groups also endow the original GDY additional advantages: the stronger electronegativity of cyano groups increase the affinity of GDY frameworks to lithium atoms, and the larger atomic volume of methyl groups increases the interlayer distance and provides more storage space and diffusion tunnels.