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Abstract Ti/TiN coatings are used in a wide range of engineering applications due to their superior properties such as high hardness and toughness. Doping Al into Ti/TiN can further enhance properties and lead to even higher performance. Therefore, studying the atomic‐level behavior of the TiAl/TiAlN interface is important. However, due to the large number of possible combinations for the 50 mol% Al‐doped Ti/TiN system, it is time‐consuming to use the DFT‐based Monte Carlo methods to find the optimal TiAl/TiAlN system with a high work of adhesion. In this study, we use a graph convolutional neural network as an interatomic potential, combined with reinforcement learning, to improve the efficiency of finding optimal structures with a high work of adhesion. By inspecting the features of structures in neural networks, we found that the optimal structures follow a certain pattern of doping Al near the interface. The electronic structure and bonding analysis indicate that the optimal TiAl/TiAlN structures have higher bonding strength. We expect our approach to significantly accelerate the design of advanced ceramic coatings, which can lead to more durable and efficient materials for engineering applications. 

Abstract Graphene-based electrodes have been extensively investigated for supercapacitor applications. However, their ion diffusion efficiency is often hindered by the graphene restacking phenomenon. Even though holey graphene is fabricated to address this issue by providing ion transport channels, those channels could still be blocked by densely stacked graphene nanosheets. To tackle this challenge, this research aims at improving the ion diffusion efficiency of microwave-synthesized holey graphene films by tuning the water interlayer spacer towards the improved supercapacitor performance. By controlling the vacuum filtration during graphene-based electrode fabrication, we obtain dry films with dense packing and wet films with sparse packing. The SEM images reveal that 20 times larger interlayer distance is constructed in the wet film compared to that in the dry counterpart. The holey graphene wet film delivers a specific capacitance of 239 F/g, ~82% enhancement over the dry film (131 F/g). By an integrated experimental and computational study, we quantitatively show that the interlayer spacing in combination with the nanoholes in the basal plane dominates the ion diffusion rate in holey graphene-based electrodes. Our study concludes that novel hierarchical structures should be further considered even in holey graphene thin films to fully exploit the superior advantages of graphene-based supercapacitors. 

Abstract High‐performance electrical conductors at higher temperatures are increasingly needed in aerospace, electric vehicles, and military applications. This study develops an innovative multilayered graphene–metal composite conductor, significantly surpassing the maximum temperature limit of conventional copper (≈90 °C for commercial wires). This approach involves integrating fine copper (Cu) wire with functional shells to exploit the high electrical conductivity and chemical inertness of silver (Ag) and graphene (G), as well as excellent anti‐oxidation of nickel (Ni). Three different composite conductors, namely, NiGCu, NiAgCu, and NiAgGCu, are synthesized, characterized, and compared to quantify their overall performance and investigate the functionality of each shell. This work highlights the importance of the G layer. For example, NiAgGCu has 29.3% lower resistivity than NiAgCu, 34% lower resistivity than NiGCu, and 18.7% higher current density limit than NiAgCu after exposure to 550–850 °C. Both molecular dynamics (MD) and finite elements (FE) simulations are performed to reveal the detailed mechanisms of unprecedented thermal stability. These theoretical studies suggest that the embedded continuous graphene layer, even with its unavoidable defects, is attributed to significant performance enhancements up to 850 °C. The results present possible strategies to address current technical bottlenecks for high‐performance electrical conductors in harsh environments.