Conductive traces printed onto compatible flexible substrates to interconnect conventional silicon-based components and printed components are key building blocks and technologically unique to flexible hybrid electronics (FHE). This form of innovative integration offers durability, flexibility, conformity, and low-temperature processing of particular relevance to applications in fields such as wearable medical devices, IoT, solar cells, communications, aerospace, and defense. [1-7] Moreover, it enables new use of materials and a wide range of applications and functionalities. This facilitate in producing low power-consumption devices allowing for rapid and large volume production at low cost. [8,9] Printed traces are fabricated using techniques such as screen printing, inkjet printing, precision dispensing, and aerosol jet printing (AJP), depending on key ink properties including the ink viscosity. [10] Among these, AJP is probably the most attractive method for fabrication of printed electronics. Fine features down to 10 μm trace width and spacing, large stand-off distances, a large ink matrix, and design flexibility are the key advantages of AJP technique. [11] AJP process starts by atomization of an ink either pneumatically (used in this study) or ultrasonically, depending on the ink viscosity and solid content size and percentage (Table 1). In the pneumatic atomizer, an inert gas (nitrogen) is applied into the ink container to form mists/aerosols of the ink (around 1-5 μm diameter). Then the aerosol flow is carried out using a carrier gas to the deposition head passing by the virtual impactor where the aerosols are filtered based on their inertia. In the deposition head, a surrounding sheath gas flow (nitrogen) is used to collimate and direct the aerosols flow stream into the substrate. Figure 1 summarizes the working principle of the pneumatic atomization. The AJP print quality is governed by many factors including ink and substrate properties and their interaction,

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Advanced materials, electrically conductive and oxidation resistant, are frontrunners for technological advancements in cutting‐edge high‐temperature electronics. Rational design and manufacturing of hierarchical material structures is indispensable to achieve such disparate functionalities. Here, high‐temperature copper–graphene conductors, through additive manufacturing, which prohibits oxygen adsorbates and serves as the barrier for oxygen migration to enable electric stability and reliability at high temperatures, are reported. The combination of graphene and alumina surface passivation enables the electric stability of copper–graphene under thermal impact above 1000 °C. The findings shown here, the synergistic combination of high conductivity and oxidation resistance, enunciate the passivation capabilities for additively manufactured flexible electronics operating under harsh conditions.

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