Observing Proton-Electron Mixed Conductivity in Graphdiyne.

Mixed conducting materials with both ionic and electronic conductivities have gained prominence in emerging applications. However, exploring material with on-demand ionic and electronic conductivities remains challenging, primarily due to the lack of correlating macroscopic conductivity with atom-scale structure. Here, the correlation of proton-electron conductivity and atom-scale structure in graphdiyne is explored. Precisely adjusting the conjugated diynes and oxygenic functional groups in graphdiyne yields a tunable proton-electron conductivity on the order of 103. In addition, a wet-chemistry lithography technique for uniform preparation of graphdiyne on flexible substrates is provided. Utilizing the proton-electron conductivity and mechanical tolerance of graphdiyne, bimodal flexible devices serving as capacitive switches and resistive sensors are created. As a proof-of-concept, a breath-machine interface for sentence-based communication and self-nursing tasks with an accuracy of 98% is designed. This work represents an important step toward understanding the atom-scale structure-conductivity relationship and extending the applications of mixed conducting materials to assistive technology.

Skin-Inspired Multi-Modal Mechanoreceptors for Dynamic Haptic Exploration.

Active sensing is a fundamental aspect of human and animal interactions with the environment, providing essential information about the hardness, texture, and tackiness of objects. This ability stems from the presence of diverse mechanoreceptors in the skin, capable of detecting a wide range of stimuli and from the sensorimotor control of biological mechanisms. In contrast, existing tactile sensors for robotic applications typically excel in identifying only limited types of information, lacking the versatility of biological mechanoreceptors and the requisite sensing strategies to extract tactile information proactively. Here, inspired by human haptic perception, a skin-inspired artificial 3D mechanoreceptor (SENS) capable of detecting multiple mechanical stimuli is developed to bridge sensing and action in a closed-loop sensorimotor system for dynamic haptic exploration. A tensor-based non-linear theoretical model is established to characterize the 3D deformation (e.g., tensile, compressive, and shear deformation) of SENS, providing guidance for the design and optimization of multimode sensing properties with high fidelity. Based on SENS, a closed-loop robotic system capable of recognizing objects with improved accuracy (≈96%) is further demonstrated. This dynamic haptic exploration approach shows promise for a wide range of applications such as autonomous learning, healthcare, and space and deep-sea exploration.

Deshielding Anions Enable Solvation Chemistry Control of LiPF6-Based Electrolyte toward Low-Temperature Lithium-Ion Batteries.

Severe capacity decay under subzero temperatures remains a significant challenge for lithium-ion batteries (LIBs) due to the sluggish interfacial kinetics. Current efforts to mitigate this deteriorating interfacial behavior rely on high-solubility lithium salts (e.g., Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), Lithium bis(fluorosulfonyl)imide (LiFSI))-based electrolytes to construct anion participated solvation structures. However, such electrolytes bring issues of corrosion on the current collector and increased costs. Herein, the most commonly used Lithium hexafluorophosphate (LiPF6) instead, to establish a peculiar solvation structure with a high ratio of ion pairs and aggregates by introducing a deshielding NO3 - additive for low-temperature LIBs is utilized. The deshielding anion significantly reduces the energy barrier for interfacial behavior at low temperatures. Benefiting from this, the graphite (Gr) anode retains a high capacity of ≈72.3% at -20 °C, which is far superior to the 32.3% and 19.4% capacity retention of counterpart electrolytes. Moreover, the LiCoO2/Gr full cell exhibits a stable cycling performance of 100 cycles at -20 °C due to the inhibited lithium plating. This work heralds a new paradigm in LiPF6-based electrolyte design for LIBs operating at subzero temperatures.

Pangolin-Inspired Stretchable, Microwave-Invisible Metascale.

Microwave-invisible devices are emerging as a valuable technology in various applications, including soft robotics, shape-morphing structures, and textural camouflages, especially in electronic countermeasures. Unfortunately, conventional microwave-absorbing metastructures and bulk absorbers are stretching confined, limiting their application in deformable or special-shaped targets. To overcome such limitations, a conceptually novel soft-rigid-connection strategy, inspired by the pangolin, is proposed. Pangolin-inspired metascale (PIMS), which is a kind of stretchable metamaterial consisting of an electromagnetic dissipative scale (EMD-scale) and elastomer, is rationally designed. Such a device exhibits robust microwave-absorbing capacity under the interference of 50% stretching. Besides, profiting from the covering effect and size-confined effect of EMD-scale, the out-of-plane indentation failure force of PIMS is at least 5 times larger than conventional device. As a proof of concept, the proposed device is conformally pasted on nondevelopable surfaces. For a spherical dome surface, the maximum radar cross-section (RCS) reduction of PIMS is 6.3 dB larger than that of a conventional device, while for a saddle surface, the bandwidth of 10 dB RCS reduction exhibits an increase of 83%. In short, this work provides a conceptually novel platform to develop stretchable, nondevelopable surface conformable functional devices.

Graphdiyne nanosheets as a platform for accurate copper(ii) ion detection via click chemistry and fluorescence resonance energy transfer.

A novel sensing platform for sensitive detection of copper(ii) ions (Cu2+) in living cells and body fluids was developed by taking advantage of the excellent fluorescence quenching ability of graphdiyne (GDY) and the high specificity of click chemistry for the first time.

Artificial Carbon Graphdiyne: Status and Challenges in Nonlinear Photonic and Optoelectronic Applications.

The creative integration of sp-hybridized carbon atoms into artificial carbon graphdiyne has led to graphdiyne with superior properties in terms of uniformly distributed pores, ambipolar carrier transport, natural bandgap, and broadband absorption. Consequently, graphdiyne, regarded as a promising carbon material, has garnered particular attention in light-matter interactions. Light-matter interactions play an important role in optical information technology and meet the increasing demand for various energy sources. Herein, the status and challenges in nonlinear photonic and optoelectronic applications of graphdiyne, which are still in the infancy stage, are summarized. Furthermore, the bottleneck and perspective of graphdiyne in these aspects are discussed. It is therefore anticipated that this review could promote the development of graphdiyne in photonic and optoelectronic fields.

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.

A facile approach for graphdiyne preparation under atmosphere for an advanced battery anode.

An explosion approach was developed for efficiently preparing graphdiynes (GDYs) at 120 °C in air without any metal catalyst. The GDYs show great superiority in terms of thermal stability, conductivity (20 S m-1) and surface area (up to 1150 m2 g-1), and can be applied as promising anodes for storing lithium/sodium ions.

Extraordinarily Durable Graphdiyne-Supported Electrocatalyst with High Activity for Hydrogen Production at All Values of pH.

We have used a scalable and inexpensive method to prepare a catalyst comprising graphdiyne nanosheet-supported cobalt nanoparticles wrapped by N-doped carbon (CoNC/GD); this unprecedentedly durable electrocatalyst mediated the hydrogen evolution reaction (HER) with highly catalytic activity over all values of pH. The durability of the CoNC/GD structure was evidenced by the catalytic performance being preserved over 36 000, 38 000, and 9000 cycles under basic, acidic, and neutral conditions, respectively-behavior superior to that of commercial Pt/C (10 wt %) under respective conditions. Such long-term durability has rarely been reported previously for HER catalysts. In addition, this electrode displayed excellent catalytic activity because the improved physical/chemical properties facilitated electron transfer in the composite. The combination of high durability and high activity at all values of pH for this nonprecious metal catalyst suggests great suitability for practical water splitting.

Controlling the Interface Areas of Organic/Inorganic Semiconductor Heterojunction Nanowires for High-Performance Diodes.

A new method of in situ electrically induced self-assembly technology combined with electrochemical deposition has been developed for the controllable preparation of organic/inorganic core/shell semiconductor heterojunction nanowire arrays. The size of the interface of the heterojunction nanowire can be tuned by the growing parameter. The heterojunction nanowires of graphdiyne/CuS with core/shell structure showed the strong dependence of rectification ratio and perfect diode performance on the size of the interface. It will be a new way for controlling the structures and properties of one-dimensional heterojunction nanomaterials.

Quantitative Detection of Visible Light on Hybrid Nanostructures of Two-dimension Porous Conjugated Polymers and Charge-Transfer Complexes by Field Emission.

We have developed a new method of in situ vapor-solid phase reaction for fabricating a kind of novel hybrid nanostructures of two-dimension (2D) porous conjugated polymers (PCPs) and charge-transfer complexes (CuTCNQ-TEPPM and CuTCNQF4 -TEPPM). These novel hybrid nanostructures have displayed excellent field emission properties and high stability. Due to the junction formed at the interface between the 2D porous conjugated polymers (PCPs) and charge-transfer complexes, the device exhibits quantitative detection and typical visible-light-dependent field emission property.