Facile Fabrication of Hybrid Copper–Fiber Conductive Features with Enhanced Durability and Ultralow Sheet Resistance for Low‐Cost High‐Performance Paper‐Based Electronics

The accelerating arrival of the Internet of Things (IoT) era creates a rapidly growing demand for paper‐based electronics due to their low cost, light weight, flexibility, and environmental friendliness. However, manufacturing high quality circuits with ultralow sheet resistance on cellulose paper remains a challenge. Here, a method is proposed to easily fabricate hybrid copper–fiber highly conductive features on low‐cost cellulose paper with strong adhesion and enhanced bending durability. A functional coating for fast surface modification of cellulose paper via an in situ cross‐linking mechanism between pyridine and epoxy groups is developed to enhance copper–fiber adhesion and protect paper in alkaline electroless deposition bath. Thanks to the unique porous structure of cellulose paper, the electroless copper deposition occurs in a 3D manner in the inkjet‐printed area, and forms a flexible copper–fiber hybrid structure ≈90 µm thick with sheet resistances as low as 0.00544 Ω sq⁻¹. To demonstrate its potential applications in the IoT industry, a functional battery‐free circuit and a high‐performance planar antenna for radio frequency identification are fabricated and tested using the proposed method.