Copper conductive inks are attracting immense interest given their augmenting contribution to the field of printed electronics, while its high-temperature conducting performance is indispensable. This study highlights a copper-based printable ink with high electrical conductivity at elevated temperatures for an increased operating life and capable of adhering to any geometric surface. The in situ formed copper−graphene printed conductor displays an electrical conductivity of 8 × 10 5 S/m and maintains its stability up to 650 °C. Furthermore, high-temperature Cu sensor electronics are fabricated by using 3D printing, which paves the way for the resistance thermometer sensors and flexible electronics applications.

Printed copper materials have been attracting significant attention prominently due to their electric, mechanical, and thermal properties. The emerging copper-based flexible electronics and energy-critical applications rely on the control of electric conductivity, current-carrying capacity, and reliability of copper nanostructures and their printable ink materials. In this review, we describe the growth of copper nanostructures as the building blocks for printable ink materials on which a variety of conductive features can be additively manufactured to achieve high electric conductivity and stability. Accordingly, the copper-based flexible hybrid electronics and energy-critical devices printed by different printing techniques are reviewed for emerging applications.

Polymer dielectrics, an insulating material ubiquitous in electrical power systems, must be ultralight, mechanically and dielectrically strong, and very thermally conductive. However, electric and thermal transport parameters are intercorrelated in a way that works against the occurrence of thermally conductive polymer electric insulators. Here, we describe how solution gel-shearing-strained polyethylene yields an electric insulating material with an outstanding in-plane thermal conductivity of 10.74 W m −1 K −1 and an average dielectric constant of 4.1. The dielectric constant and loss of such sheared polymer electric insulators are nearly independent of the frequency and a wide temperature range. The gel-shearing aligns ultrahigh-molecular weight polymer crystalline chains for the formation of separated and aligned nanoscale fibrous arrays. Together with lattice strains and the presence of boron nitride nanosheets, the dielectric polymer shows high current density carrying and high operating temperature, which is attributed to greatly enhanced heat conduction.

Recent advances in the field of flexible electronics have garnered immense attention. Flexible pressure sensors with high sensitivity and the capability of being additively manufactured are becoming crucial for monitoring signals pertaining to various stimuli. Herein, we describe a conformal resistive pressure sensor by direct writing of metal nanowires onto flexible ceramics for impact sensing and pressure monitoring under extreme environments. The conformal pressure sensor shows a sensitivity of 1.45 kPa −1 for static pressures as low as 49 Pa to 4905 Pa, a fast response time of 70 ms, and high cyclic stability and reliability (>1000 cycles). It can also be utilized for wireless detection of impacts and pressure impacts as a consequence of laser shockwaves with resulting dynamic pressures ranging from 0.17−0.29 MPa. The printed pressure sensor also displays the capability of detecting the pulse and providing vital information regarding the arterial physical situation in a noninvasive way. The findings shown here detail the capability of sensor electronics with the capability of additive manufacturing for next-generation flexible hybrid electronics.

Copper has attracted immense interest in advanced electronics attributed to its abundance and high electrical and thermal characteristics. However, the ease of oxidation when subjected to heat and humidity drastically limits its material reliability under extreme environments. Here, we utilize copper nanoplates as a building block to achieve a thermally stable (upwards of 1300 °C), antioxidation, and anticorrosion-printed conductor, with the capability of additively manufacturing on Corning flexible Alumina Ribbon Ceramic. We elucidate the printed copper nanoplates with a low sheet resistance of 4 mΩ/sq/mil by means of a surfacecoordinated formate that inculcates high oxidation and corrosion resistance on a molecular level. In addition, an in situ copper− graphene conversion leads to a hybridized conductor displaying stability at elevated temperatures up to 1300 °C with high ampacity. Further mechanistic studies reveal high-temperature stability from in situ graphene conversion for copper and graphene interfaces, and preferential stacking of copper nanoplates, distinctly suited for emerging high-temperature flexible electronics.