Durable Near-Zero Wear Behavior Achieved by Polymer-Based Protic Ionic Liquids on Engineering Steel Surfaces.

Near-zero wear on engineering steel surfaces is a promising solution to extend the service life of mechanical equipment. However, most existing strategies offer only limited low wear under particular conditions and friction pairs. To address this, we design a polymer-based proton ionic liquid (PPILs) lubricant, leveraging the proton exchange between polyethylenimine, which is rich in active nitrogen groups, and bis(2-ethylhexyl) phosphate.

Gas Modulation Induced Ultra-Low Friction and Ultra-Strong Wear Resistance in Atomically Thin MoSe Single Crystals.

Atomically thin films exhibiting ultra-low friction and ultra-strong wear resistance are crucial for overcoming lubrication challenges in micro-nano electromechanical systems (M/NEMS). However, achieving these properties under conventional pressure conditions remains a major challenge. In this study, a novel strategy is presented to further reduce friction and enhance wear resistance by tuning the atmosphere composition.

A Fluorinated Anodic Aluminum Oxide Nanopores Coating Triboelectric Nanogenerator for Self-healing Triboelectrification and Anti-corrosion.

The triboelectric layer is a key component affecting the performance of a triboelectric nanogenerator (TENG). Herein, a TENG with a triboelectric layer possessing a fluorinated-anodic-alumina-nanopores structure was prepared. The nanopores structure can increase the contact area and thus increase the triboelectric output.

Ultrastrong eutectogels engineered via integrated mechanical training in molecular and structural engineering.

Ultrastrong gels possess generally ultrahigh modulus and strength yet exhibit limited stretchability owing to hardening and embrittlement accompanied by reinforcement. This dilemma is overcome here by using hyperhysteresis-mediated mechanical training that hyperhysteresis allows structural retardation to prevent the structural recovery of network after training, resulting in simply single pre-stretching training. This training strategy introduces deep eutectic solvent into polyvinyl alcohol hydrogels to achieve hyperhysteresis via hydrogen bonding nanocrystals on molecular engineering, performs single pre-stretching training to produce hierarchical nanofibrils on structural engineering, and fabricates chemically cross-linked second network to enable stretchability.

Target High-Efficient Ethylene Production from Dilute CO Enabled by Sustainable Contact Electrons.

The electrochemical CO reduction reaction (CORR) exhibits significant potential to efficiently convert CO into ethylene (CH). However, achieving high CH selectivity remains a considerable challenge due to the difficulty in effective C─C coupling and stringent requirements on CO purity. Herein, a novel contact-electro-catalysis method for CORR is presented by constructing dual-active-site catalysts on the electronegative tribolayer of a triboelectric nanogenerator (TENG), including single copper atom anchored polymeric carbon nitride (Cu─PCN) and CuO nanoparticle, achieving an outstanding CH Faradaic efficiency of 63.

Droplet-Based Triboelectric Nanogenerators with Needle Electrodes for Efficient Water Energy Harvesting.

With the advent of droplet-based triboelectric nanogenerators (D-TENGs), methods for converting raindrop kinetic energy to electrical energy have developed rapidly. However, current D-TENG designs suffer from slow solid-liquid interface separation speeds and susceptibility to liquid residues. These issues compromise the output performance of D-TENGs and limit their applications in high-power electrical appliances.

Constructing a Conductive Micro/Nano Network Within Interpenetrating Phase Composites for Triboelectric Nanogenerators.

Interpenetrating phase composites (IPCs) are gaining popularity because of their unique topological characteristics, which include their light weight and ability to conduct electricity. Herein, a novel metal‒polymer IPC composed mainly of a 3D nickel foam(NF) at the microscale and a polytetrafluoroethylene (PTFE) matrix are developed. Moreover, a nanonetwork composed of carbon nanotubes (CNTs) bridging the nickel skeleton and PTFE matrix is created within the IPC via a simple impregnation method.

Macro-Superlubricity Induced by Tribocatalysis of High-Entropy Ceramics.

Macroscale superlubricity has attracted considerable attention as a promising strategy to minimize frictional energy dissipation and achieve near-zero wear. However, realizing macroscale superlubricity with prolonged durability remains an immense challenge, particularly on engineering steels. Current superlubricants render steel surfaces susceptible to corrosion, causing severe wear and superlubrication failure.

Macroscale Superlubrication Achieved with Shear-Thinning Semisolid Lubricants.

Macrosuperlubric materials are pivotal for reducing friction and wear in engineering applications. However, current solid superlubricants require intricate fabrication and specific conditions (e.g.

High-Output Triboelectric Nanogenerator Achieved through Conductive Layer Strategy for Motion Step Sensing.

As an emerging high-efficiency energy conversion device, improving the output of triboelectric nanogenerators (TENGs) is still a key method to promote practical application of TENGs. This paper systematically investigated the influence of component composition, thickness, and surface morphology of the metal conducting layer on the performance of triboelectric nanogenerators. It has been established that these three factors have a significant influence on the output performance of TENGs.

Contact-electro-catalytic CO reduction from ambient air.

Traditional catalytic techniques often encounter obstacles in the search for sustainable solutions for converting CO into value-added products because of their high energy consumption and expensive catalysts. Here, we introduce a contact-electro-catalysis approach for CO reduction reaction, achieving a CO Faradaic efficiency of 96.24%.

A high-performance triboelectric nanogenerator with dual nanostructure for remote control of switching circuit.

Preparing nanostructured surfaces has been considered an effective method to improve the output of triboelectric nanogenerators (TENGs), but how to quickly prepare materials with a nanostructured surface for TENGs has always been a challenge. Here, polypropylene nanowires and electrospun nylon 11 nanofibers were successfully prepared through a simple and time-saving method with a high success rate. Compared with a flat TENG, the output performance of a dual nanostructured TENG is enhanced by more than 5 times.

Revamping Triboelectric Output by Deep Trap Construction.

High output performance is critical for building triboelectric nanogenerators (TENGs) for future multifunctional applications. Unfortunately, the high triboelectric charge dissipation rate has a significant negative impact on its electrical output performance. Herein, a new tribolayer is designed through introducing self-assembled molecules with large energy gaps on commercial PET fibric to form carrier deep traps, which improve charge retention while decreasing dissipation rates.

Visualization of Charge Dynamics when Water Droplets Bounce on a Hydrophobic Surface.

Visualizing the motion of water droplets and understanding their electrification behavior holds significance for applications related to droplet transport, self-cleaning, and anti-icing/deicing and for providing a comprehensive explanation of the solid-liquid triboelectrification mechanism. Here, by constructing microcolumnar structures on the polytetrafluoroethylene surface, a water droplet-based single electrode triboelectric nanogenerator was fabricated for visualizing charge dynamics when a water droplet bounces on a hydrophobic surface. The motion state of the water droplet is closely linked to its electrification behavior through the integration of a high-speed camera and an ammeter.

High-Output Single-Electrode Droplet Triboelectric Nanogenerator Based on Asymmetrical Distribution Electrostatic Induction Enhancement.

Droplet-based triboelectric nanogenerators (D-TENGs) have recently gained much attention due to their great potential in harvesting energy. However, the output performance of conventional single-electrode droplet-based TENGs is limited owing to low induced electrification efficiency. The asymmetric distribution of electric fields on both sides of the electrode edge enhances the electrostatic induction process and improves the output performance of D-TENG.

Monolayer NbSe Favors Ultralow Friction and Super Wear Resistance.

The urgent demand for atomically thin, superlubricating, and super wear-resistant materials in micro/nanoelectromechanical systems has stimulated the research of friction-reducing and antiwear materials. However, the fabrication of subnanometer-thick films with superlubricating and super wear-resistant properties under ambient conditions remains a huge challenge. Herein, high-quality monolayer (ML) NbSe (∼0.

Macroscale Superlubricity with Ultralow Wear and Ultrashort Running-In Period (∼1 s) through Phytic Acid-Based Complex Green Liquid Lubricants.

Liquid superlubricity has attracted much attention, due to its ability to significantly reduce friction on the macroscale. However, the severe wear caused by the long running-in period is still one of the bottlenecks restricting the practical application of liquid superlubricating materials. In this work, the obtained polyethylene glycol-phytic acid (PEG-PA) composite liquid lubricants showed outstanding superlubricating properties (μ ≈ 0.

Deep Trap Boosted Ultrahigh Triboelectric Charge Density in Nanofibrous Cellulose-Based Triboelectric Nanogenerators.

For their use in self-powered implantable or wearable electronics, cellulose nanofiber (CNF)-based triboelectric nanogenerators (TENGs) have drawn a lot of attention. However, the low triboelectric charge density (TECD) hinders its further application as a tribolayer for TENGs. In this work, a sulfonated cellulose nanofiber was prepared as an electropositive tribolayer for TENGs to obtain ultrahigh electrical output performance.

Gas-liquid two-phase flow-based triboelectric nanogenerator with ultrahigh output power.

Solid-liquid triboelectric nanogenerators (SL-TENGs) have shown promising prospects in energy harvesting and application from water resources. However, the low contact separation speed, small contact area, and long contacting time during solid-liquid electrification severely limit their output properties and further applications. Here, by leveraging the rheological properties of gas-liquid two-phase flow and the Venturi-like design, we circumvent these limitations and develop a previously unknown gas-liquid two-phase flow-based TENG (GL-TENG) that can achieve ultrahigh voltage and volumetric charge density of 3789 volts and 859 millicoulombs per cubic meter, respectively.

Control of triboelectrification on Al-metal surfaces through microstructural design.

The instantaneous discharge of accumulated static charge due to contact electrification can cause irreversible damage to electrostatic-sensitive systems. Despite major advances in reducing tribo-charges, the problem remains intractable. Here, four alumina microstructures are fabricated on aluminum (Al) by combining chemical etching and anodic oxidation, and the effects of surface composition and structure on the triboelectric performance are studied by assembling them with a polytetrafluoroethylene membrane into a solid-solid triboelectric nanogenerator.

A β-cyclodextrin enhanced polyethylene terephthalate film with improved contact charging ability in a high humidity environment.

Moisture in the environment can severely decrease the contact charging properties of polymers, which usually reduce the output of solid-solid triboelectric nanogenerators (TENGs), hindering their further practical applications. To solve this problem, in this paper we fabricated a new type of polyethylene terephthalate (PET) based TENG, which can work stably in a high humidity environment with high output performance. The surface of the PET film is modified with β-cyclodextrin to introduce hydroxyl groups, which increase the ability to form hydrogen bonds with water molecules in a high humidity environment, immobilizing water molecules to participate in contact charging.

Quantifying Wetting Dynamics with Triboelectrification.

Wetting is often perceived as an intrinsic surface property of materials, but determining its evolution is complicated by its complex dependence on roughness across the scales. The Wenzel (W) state, where liquids have intimate contact with the rough surfaces, and the Cassie-Baxter (CB) state, where liquids sit onto air pockets formed between asperities, are only two states among the plethora of wetting behaviors. Furthermore, transitions from the CB to the Wenzel state dictate completely different surface performance, such as anti-contamination, anti-icing, drag reduction etc.

A New Reversible Thermosensitive Liquid-Solid TENG Based on a P(NIPAM-MMA) Copolymer for Triboelectricity Regulation and Temperature Monitoring.

Intelligent and highly precise control of liquid-solid triboelectricity is of great significance for energy collection and electrostatic prevention. However, most of the traditional methods are irreversible and complex, greatly limiting their applicability. Here, a reversible thermosensitive liquid-solid triboelectric nanogenerator (L-S TENG) is assembled based on P(NIPAM-MMA) (PNM) copolymer for tunable triboelectrification.