When two insulating, neutral materials are contacted and separated, they exchange electrical charge ¹ . Experiments have long suggested that this ‘contact electrification’ is transitive, with different materials ordering into ‘triboelectric series’ based on the sign of charge acquired ² . At the same time, the effect is plagued by unpredictability, preventing consensus on the mechanism and casting doubt on the rhyme and reason that series imply ³ . Here we expose an unanticipated connection between the unpredictability and order in contact electrification: nominally identical materials initially exchange charge randomly and intransitively, but—over repeated experiments—order into triboelectric series. We find that this evolution is driven by the act of contact itself—samples with more contacts in their history charge negatively to ones with fewer contacts. Capturing this ‘contact bias’ in a minimal model, we recreate both the initial randomness and ultimate order in numerical simulations and use it experimentally to force the appearance of a triboelectric series of our choosing. With a set of surface-sensitive techniques to search for the underlying alterations contact creates, we only find evidence of nanoscale morphological changes, pointing to a mechanism strongly coupled with mechanics. Our results highlight the centrality of contact history in contact electrification and suggest that focusing on the unpredictability that has long plagued the effect may hold the key to understanding it.

MXenes are a 2D materials (2DM) class with high industrialization potential, owing to their superb properties and compositional variety. However, ensuring high etching efficiency in the synthesis process without involving toxic, hazardous or non‐sustainable chemicals are challenging. In this work, an upscalable electrochemical MXene synthesis is presented. This novel protocol uses a non‐toxic and sustainable sodium tetrafluoroborate/hydrochloric acid (NaBF ₄ /HCl) electrolyte and increases etching efficiency by applying cathodic pulsing via pulse voltammetry. Hydrogen bubble formation restores electrochemical activity, and effectively supports 2D‐sheet removal, allowing continuous etching at higher yields in situ. In detail, yields of up to 60% electrochemical MXene (EC‐MXene) with no byproducts from a single exfoliation cycle are achieved. EC‐MXene had an excellent quality with high purity as assessed using chemical mapping by scanning electron microscopy with energy dispersive electron spectroscopy (SEM/EDX) and surface termination analysis performed with X‐ray photoelectron spectroscopy (XPS) and, for the first time, with low energy ion scattering (LEIS). Further properties of EC‐MXenes such as dimensions and adhesion energy of single flakes, vibrational peaks, and interlayer spacing are provided by atomic force microscopy (AFM), X‐ray diffraction (XRD), Raman spectroscopy (Raman), and transmission electron microscopy (TEM) respectively. Pulsed electrochemical synthesis is key to surface reactivation at the electrodes' interface, which results in improved exfoliation and quality of EC‐MXenes. This paves the way for scaling up and green industrialization of MXenes.

The aeronautical industry demands facile lightweight and low-cost solutions to address climate crisis challenges. Graphene can be a valid candidate to tackle these functionalities, although its upscalability remains difficult to achieve. Consequently, graphene-related materials (GRM) are gathering massive attention as top-down graphite exfoliation processes at the industrial scale are feasible and often employed. In this work, environmentally friendly produced partially oxidized graphene nanosheets (POGNs) reduced by green solvents such as l-Ascorbic Acid to rGNs are proposed to deliver functional coatings based on a glass fiber composite or coated Al2024 T3 for strategic R&D questions in the aeronautical industry, i.e., low energy production, de-icing, and water uptake. In detail, energy efficiency in rGNs production is assessed via response-surface modeling of the powder conductivity, hence proposing an optimized reduction window. De-Icing functionality is verified by measuring the stable electrothermal property of an rGNs based composite over 24 h, and water uptake is elucidated by evaluating electrochemical and corrosion properties. Moreover, a mathematical model is proposed to depict the relation between the layers' sheet resistance and applied rGNs mass per area, which extends the system to other graphene-related materials, conductive two-dimensional materials, and various substrates. To conclude, the proposed system based on rGNs and epoxy paves the way for future multifunctional coatings, able to enhance the resistance of surfaces, such as airplane wings, in a flight harsh environment.

An airplane is statistically struck by lightning every year. The need for lightweight aircraft to reduce the production of carbon dioxide has significantly reduced the presence of metals in favour of composites, resulting in lower lightning strike protection efficiency. In this perspective, we critically review the state of technologies in lightning strike protection solutions based on carbon materials, graphene, and MXenes. Furthermore, we comment on possible future research directions in the field.

The degradation and aging of carbon felt electrodes is a main reason for the performance loss of Vanadium Redox Flow Batteries over extended operation time.

The industrial production of tungsten powder is carried out by the reduction of tungsten oxide powder via hydrogen. In this process, the size of the W particles is limited to particle sizes larger than 100 nm. To get below this limit, alternative processes are needed. In the current work, the possibility of preparing W powder below 100 nm via a vapour phase reduction of volatile WO₂(OH)₂ by hydrogen was investigated. The process consists of two stages. In the first stag,e WO₂(OH)₂ is formed by reacting WO₃ with water vapour at temperatures of 1000–1100 °C. In the second stage, WO₂(OH)₂ is reduced by hydrogen at about 1000 °C to form metallic tungsten. The influence of process parameters such as furnace temperature, humidity and gas flow on the WO₂(OH)₂ evaporation and formation of tungsten powder was investigated. The characterization of the resulting powders was performed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). By optimization of the reaction conditions, powder with a metallic tungsten content of about 70 at% besides tungsten oxides was produced with metal particle sizes down to 5 nm. Further optimization should lead to a high tungsten content and a high product yield. Due to the small particle size, applications in catalysis might be possible, although an industrial realization of the process seems unrealistic at moment.