Self-Adaptive Graphdiyne/Sn Interface for High-Performance Sodium Storage.

Efficiently reconciling the substantial volume strain with maintaining the stabilities of both interfacial protection and three-dimensional (3D) conductive networks is a scientific and technical challenge in developing tin-based anodes for sodium ion storage. To address this issue, a proof-of-concept self-adaptive protection for the Sn anode is designed, taking advantage of the arbitrary substrate growth of graphdiyne. This protective layer, employing a flexible chain doping strategy, combines the benefits of 2D graphdiyne and linear chain structures to achieve 2D mechanical stability, electronic and ion conductions, ion selectivity, adequate elongation, and flexibility. It establishes close contact with the Sn particles and can adapt to dynamic size changes while effectively facilitating both electronic and ion transports. It successfully mitigates the detrimental effects of particle pulverization and coarsening induced by large-volume changes. The as-obtained Sn electrodes demonstrate exceptional stability, enduring 1800 cycles at a high current density of 2.5 A g-1. This strategy promises to address the general issues associated with large-strain electrodes in next-generation of high-energy-density batteries.

A Low-Strain Cathode by sp-Carbon Induced Conversion in Multi-Level Structure of Graphdiyne.

A multi-level architecture formed alternatively by the conformal graphdiyne (GDY) and CuS is well engineered for Li-free cathode. Such a proof-of-concept architecture efficiently integrates the advantages of GDY and produces new functional heterojunctions (sp-C-S-Cu hybridization bond). The layer-by-layer 2D confinement effect successfully avoids structural collapse, the selective transport inhibits the shuttling of active components, and the interfacial sp-C-S-Cu hybridization bond significantly regulates the phase conversion reaction. Such new sp-C-S-Cu hybridization of GDY greatly improves the reaction dynamics and reversibility, and the cathode delivers an energy density of 934 Wh kg-1 and an unattenuated lifespan of 3000 cycles at 1 C. Our results indicate that the GDY-based interface strategy will greatly promote the efficient utilization of the conversion-type cathodes.

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.

Interfacial Evolution of the Solid Electrolyte Interphase and Lithium Deposition in Graphdiyne-Based Lithium-Ion Batteries.

All-carbon graphdiyne (GDY)-based materials have attracted extensive attention owing to their extraordinary structures and outstanding performance in electrochemical energy storage. Straightforward insights into the interfacial evolution at GDY electrode/electrolyte interface could crucially enrich the fundamental comprehensions and inspire targeted regulations. Herein, in situ optical microscopy and atomic force microscopy monitoring of the GDY and N-doped GDY electrodes reveal the interplay between the solid electrolyte interphase (SEI) and Li deposition. The growth and continuous accumulation of the flocculent-like SEI is directly tracked at the surface of GDY electrode. Moreover, the nanoparticle-shaped SEI homogeneously propagates at the interface when N configurations are involved, providing a critical clue for the N-doping effects of stabilizing interfaces and homogenizing Li deposition. This work probes into the dynamic evolution and structure-reactivity correlation in detail, creating effective strategies for GDY-based materials optimization in lithium-ion batteries.

Controlled Growth of 3D Interpenetrated Networks by NiCo2O4 and Graphdiyne for High-Performance Supercapacitor.

In this paper, the 2D all-carbon graphdiyne, which possesses superior 2D strength and high mixed conductivities for both electrons and ions, is used to protect nickel cobalt oxide nanostructures with multidimensions. The in situ grown graphdiyne seamlessly wraps on nanostructures to form 3D interpenetrating networks, leading to significant improvement in the conductivity and avoidance of the structural degradation. The assembled hybrid asymmetric supercapacitor showed a high specific capacitance of 200.9 F g-1 at 1 A g-1 with an energy density of 62.8 Wh kg-1 and a power density of 747.9 W kg-1. The device also showed a preeminent rate capability (86.4% capacitance retention, while the current density was increased from 1 to 20 A g-1) and an ultrastable long-term cycling performance (the capacitance retention is about 97.7% after 10 000 cycles at a high current density of 20 A g-1).

Ultrathin graphdiyne nanosheets confining Cu quantum dots as robust electrocatalyst for biosensing featuring remarkably enhanced activity and stability.

There is an urgent need for developing electrochemical biosensor based on the acetylcholinesterase (AChE) inhibition to real-time analysis of organophosphorus pesticides (OPs), but it is suffered from the sluggish electrode kinetics and high oxidation potential toward signal species. Herein, a nanocomposite of ultrafine Cu quantum dots (QD) uniformly loaded on three-dimensional ultrathin graphdiyne (GDY) nanosheets (denoted as Cu@GDY) was synthesized via a one-step strategy, which showing high-density of active sites with persistent stability. Then an AChE biosensor based on Cu@GDY was fabricated to detect OPs, and the results revealed that the Cu@GDY nanocomposite can significantly amplifies electrochemical signal and reduces the oxidation potential for OPs. The strong interaction between active site of Cu@GDY and thiocholine signal species caused rapid analyte aggregation and decreased the reaction activation energy of thiocholine electro-oxidation. Benefiting from the excellent catalytic activity of Cu@GDY nanocomposite and reasonable regulation of enzyme inhibition kinetics, the biosensor achieved rapid and sensitive detection of OPs with a detection limit of 1 µg L-1 for paraoxon. Furthermore, the biosensor demonstrated great reproducibility, good stability and high recovery rate for OPs detection in real samples. Cu@GDY based sensor also displayed high catalytic activities and good selectivity to the non-enzymatic detection of glucose in alkaline medium. Cu@GDY offers a versatile and promising platform for sensors and biosensors featuring remarkably enhanced activity and stability, and can be applied to many other fields as desirable electrocatalyst.

Stabilizing Interface pH by N-Modified Graphdiyne for Dendrite-Free and High-Rate Aqueous Zn-Ion Batteries.

Zn dendrite issue was intensively studied via tuning zinc ion flux. pH change seriously influences dendrite formation, while its importance has not been revealed. Here, we construct a N-modification graphdiyne interface (NGI) to stabilize pH by mediating hydrated zinc ion desolvation. Operando pH detection reveals pH stabilization by NGI. This works with pores in NGI to achieve dendrite-free Zn deposition and an increased symmetric cell lifespan by 116 times. Experimental and theoretical results owe pH stabilization to desolvation with a reduced activation energy achieved by electron transfer from solvation sheath to N atom. The efficient desolvation ensures that electron directly transfers from substrate to Zn2+ (rather than the coordinated H2 O), avoiding O-H bond splitting. Hence, Zn-V6 O13 battery achieves a long lifespan at 20.65 mA cm-2 and 1.07 mAh cm-2 . This work reveals the significance of interface pH and provides a new approach to address Zn dendrite issue.

Crystalline Fully Carboxylated Polyacetylene Obtained under High Pressure as a Li-Ion Battery Anode Material.

Substituted polyacetylene is expected to improve the chemical stability, physical properties, and combine new functions to the polyacetylene backbones, but its diversity is very limited. Here, by applying external pressure on solid acetylenedicarboxylic acid, we report the first crystalline poly-dicarboxylacetylene with every carbon on the trans-polyacetylene backbone bonded to a carboxyl group, which is very hard to synthesize by traditional methods. The polymerization is evidenced to be a topochemical reaction with the help of hydrogen bonds. This unique structure combines the extremely high content of carbonyl groups and high conductivity of a polyacetylene backbone, which exhibits a high specific capacity and excellent cycling/rate performance as a Li-ion battery (LIB) anode. We present a completely functionalized crystalline polyacetylene and provide a high-pressure solution for the synthesis of polymeric LIB materials and other polymeric materials with a high content of active groups.

High Voltage-Stabilized Graphdiyne Cathode Interface.

Suppressing the irreversible interfacial reactions is an important scientific bottleneck in the development of stable high-energy-density lithium-ion battery. The interfacial chemistry of graphdiyne (GDY) on the high-voltage cathode of LiNi0.5 Mn1.5 O4 (LNMO) shows a very interesting process, in which the sp-hybridization carbon atoms chemically scavenge the hydrofluoric acid (HF) and in situ form the fluorinated GDY interface. It first turns the harmful HF into profit, and greatly enhances the interfacial stability and restrains the side reaction on the cathode under high working voltage. The GDY-coated LNMO cathode obviously alleviates the electrolyte degradation, achieves high Coulombic efficiency and reliability. Due to atomic-level selectivity and chemical trapping of HF by GDY, it effectively suppresses the dissolution of Mn, Ni elements. These results highlight the unparalleled advantages of GDY in the formation of high stable interfaces and protection of high-energy-density electrodes.

Spontaneously Splitting Copper Nanowires into Quantum Dots on Graphdiyne for Suppressing Lithium Dendrites.

As an emerging carbon allotrope, the controllable growth of graphdiyne has been an important means to explore its unique scientific properties and applications. In this work, the effect of the crystal structure of copper (Cu) on the growth of graphdiyne is systematically studied. It is found that the crystal boundaries are the origin of the reaction activity. The polycrystalline Cu nanowire with many crystal boundaries is spontaneously split into Cu quantum dots (about 3 nm) by the grown graphdiyne. These Cu quantum dots are uniformly dispersed on the graphdiyne, and they block the long-range ordered growth of the graphdiyne. These Cu quantum dots in situ supported on graphdiyne demonstrate high efficiency in inhibiting the growth of lithium dendrites in lithium metal batteries. Based on this interesting finding, the Cu quantum dots anchored on the all-carbon graphdiyne can be prepared on a large scale, and unique applications of Cu quantum dots in electrochemical fields can be implemented.

High Quality Pyrazinoquinoxaline-Based Graphdiyne for Efficient Gradient Storage of Lithium Ions.

N-doping of graphdiyne with atomic precision is very important for the study of heteroatom doping effect and the structure-properties relationships of graphdiyne. Here we report the bottom-up synthesis and characterizations of high-quality pyrazinoquinoxaline-based graphdiyne (PQ-GDY) film. First-principle studies of the layered structure were performed to examine the stacking mode, lithium binding affinity, and bulk lithium storage capacity. Three-stage insertion of 14 lithium atoms with binding affinities in the order of pyrazine nitrogen > diyne carbon > central aromatic ring were confirmed by both lithium-ion half-cell measurements and DFT calculations. More than half of the lithium atoms preferentially bind to pyrazine nitrogen, and a reversible capacity of 570.0 mA h g-1 at a current density of 200 mA g-1 after 800 cycles was achieved. Such a high capacity utilization rate of 97.2% provides a good case study of N-doped GDY with atomic precision.

In Situ Coating Graphdiyne for High-Energy-Density and Stable Organic Cathodes.

The preparation of organic small-molecule cathodes is simple and low-cost; however, their low conductivity and molecular dissolution are two key issues that mean their energy density and power performance are far lower than those of inorganic batteries, thus hindering their practical application. To develop an effective coating technology is the key to obtain high-performance organic batteries. A general method of in situ weaving all-carbon graphdiyne nanocoatings is demonstrated. The graphdiyne can be conformally weaved on organic particles under mild conditions so that the conductivity is increased and the dissolution is suppressed. After weaving graphdiyne nanocoat, the active mass of the small-molecule organic cathodes rise to 93%, thus delivering a higher energy density of 310 W h kg-1 than previously reported, and the power performance and long-term stability are greatly improved. Additionally, this method shows great potential to become the crucial technology for fabricating organic batteries with energy density close to prevailing lithium-ion batteries.

N-Doped Graphdiyne Coating for Dendrite-Free Lithium Metal Batteries.

Nonuniform nucleation is one of the major reasons for the dendric growth of metallic lithium, which leads to intractable problems in the efficiency, reversibility, and safety in Li-based batteries. To improve the deposition of metallic Li on Cu substrates, herein, a freestanding current collector (NGDY@CuNW) is formed by coating pyridinic nitrogen-doped graphdiyne (NGDY) nanofilms on 3D Cu nanowires (CuNWs). Theoretical predictions reveal that the introduction of nitrogen atoms in the 2D GDY can enhance the binding energy between the Li atom and GDY, therefore improving the lithiophilicity on the surface for uniform lithium nucleation and deposition. Accordingly, the deposited metallic Li on the NGDY@CuNW electrode exhibits a dendrite-free morphology, resulting in significant improvements in terms of the reversibility with a high coulombic efficiency (CE) and a long lifespan at high current density. Our research provides an efficient method to control the surface property of Cu, which also will be instructive for other metal batteries.

Controllable Synthesis of Graphdiyne Nanoribbons.

Graphdiyne nanoribbons with high chemical precision are of great significance for further understanding of the intrinsic properties of graphdiyne and the relationship between structure and properties. However, the reliable synthesis of graphdiyne nanoribbons with chemical precision remains a significant challenge. A facile method is now presented for fabrication of graphdiyne nanoribbons with uniform width through stepwise inter- and intramolecular Glaser-Hay coupling reaction of ethynyl groups. The synthetic ribbons were interwoven into nanotextiles by π-π stacking and were applied for protective coating of Li-electrode in Li-ion batteries, which efficiently suppressed the growth of the Li dendrites during cycling and prolonged the life span of Li-metal batteries.

Large-Area Aminated-Graphdiyne Thin Films for Direct Methanol Fuel Cells.

A two-dimensional (2D) carbon nanofilm with uniform artificial nanopores is an ideal material to ultimately suppress the fuel permeation in the proton exchange membrane fuel cells. Graphdiyne has great mechanical strength, high dimensional stability, and controllable nanopores, and has good prospects to play this crucial role. It is found that graphdiyne nanofilm with amino groups and natural nanopores can be easily prepared with high integrity. The aminated graphdiyne has good compatibility with the Nafion matrix owing to the acid-base interaction between them. The excellent comprehensive properties of graphdiyne in selectivity, dimensional stability, and integrity effectively improve the power performance and stability of fuel cells at wide temperature. Our results can be developed into a universal method that can easily realize the selective separation of ions and small molecules, and open a new way for the emerging applications in green energy.

Highly Lithiophilic Graphdiyne Nanofilm on 3D Free-Standing Cu Nanowires for High-Energy-Density Electrodes.

The sp-hybridization carbon atoms in graphdiyne (GDY) are higher lithiophilic epicenters for lithium (Li) deposition than those of sp2-hybridized ones in traditional carbon materials. The ultrathin GDY nanofilms are constructed in situ on the 3D free-standing Cu nanowires (CuNWs) for improving the lithiophilicity of the surface efficiently. The CuNW electrode modified by GDY nanofilms (GDY@CuNW) shows significant improvements in terms of overpotential for lithium nucleation, battery lifespan, Coulombic efficiency, and suppression of dendritic lithium. The overall improvement of the free-standing electrode exhibits a volumetric capacity high up to 1333 mA h cm-3. Our results have demonstrated that controllable growth of GDY nanofilms should be an effective method to improve the Li plating and stripping process in the Li metal battery.

Ultrafastly Interweaving Graphdiyne Nanochain on Arbitrary Substrates and Its Performance as a Supercapacitor Electrode.

A moderate method is first developed here for superfast (in seconds) growth of an ultrafine graphdiyne (GDY) nanochain on arbitrary substrates in the atmosphere. This is an environmentally friendly and metal-catalyst-free method, efficiently eliminating extraneous contaminations for the carbon materials. The seamless GDY coating on any substrates demonstrates that an all-carbon GDY possesses outstanding controllability and processability, perfectly compensating for the drawbacks of prevailing all-carbon materials. After the decoration of 3D GDY nanostructures, the substrates become superhydrophobic with contact angles high up to of 148° and can be used as outstanding frameworks for storing organic pollution. Because of the reasonable porous and 3D continuous features, the as-prepared samples can be applied as high-performance binder-free supercapacitor electrodes with high area capacitance of up to 53.66 mF cm -2, prominent power performance, and robust long-term retention (99% after 1300 cycles).

Graphdiyne Sponge for Direct Collection of Oils from Water.

Although several sponge-like sorbents have been developed to treat oil spills and chemical leakages, under harsh conditions (e.g., strong acid or alkali; oils on the sea) their efficiencies can be rather limited. Herein, we provide a graphdiyne sponge that is capable of collecting oil pollution effectively. This graphdiyne sponge exhibits excellent adsorption capacity (up to 160 times its own weight), robust stability (even when immersed in strong acid and alkali for 7 days), and remarkable recyclability (up to 100 times). These features suggest that this new adsorbent material might find applicability in the cleanup of oil spills and many organic pollutants under realistic conditions.

Synthesis and Applications of Graphdiyne-Based Metal-Free Catalysts.

The development of carbon materials offers the hope for obtaining inexpensive and high-performance alternatives to substitute noble-metal catalysts for their sustainable application. Graphdiyne, the rising-star carbon allotrope, is a big family with many members, and first realized the coexistence of sp- and sp2 -hybridized carbon atoms in a 2D planar structure. Different from the prevailing carbon materials, its nonuniform distribution in the electronic structure and wide tunability in bandgap show many possibilities and special inspirations to construct new-concept metal-free catalysts, and provide many opportunities for achieving a catalytic activity comparable with that of noble-metal catalysts. Herein, the recent progress in synthetic methodologies, theoretical predictions, and experimental investigations of graphdiyne for metal-free catalysts is systematically summarized. Some new perspectives of the opportunities and challenges in developing high-performance graphdiyne-based metal-free catalysts are demonstrated.

A Universal Strategy for Constructing Seamless Graphdiyne on Metal Oxides to Stabilize the Electrochemical Structure and Interface.

The structural and interfacial stabilities of metal oxides (MOs) are key issues while facing the volumetric variation and intensive interfacial polarization in electrochemical applications, including lithium-ion batteries (LIBs), supercapacitors, and catalysts. The growth of a seamless all-carbon interfacial layer on MOs with complex dimensions is not only a scientific problem, but also a practical challenge in these fields. Here, the growth of graphdiyne under ultramild condition is successfully implemented in situ for coating MOs of complex dimensions. The seamless all-carbon interface and conductive network are formed at the same time. This method cleverly avoids the structural degradation of MOs at a high temperature in the presence of traditional carbon materials. Under the protection of the high-quality graphdiyne layer, the samples as LIB anodes deliver high performances in terms of Coulomb efficiency, capacity, long-term retention, and structural and interfacial stabilities. Both experimental achievements and theoretical calculations demonstrate that the graphdiyne is a particular protection layer for MOs and plays a crucial role for preventing the structural and interfacial degradation of the electrode. Furthermore, the universality of this method will promote the potential applications of many promising MOs in other electrochemical fields.