Non‐Epitaxial Growth of Transition Metal Oxide Crystalline Nanorods on Laser‐Induced Graphene

Abstract Laser‐induced graphene (LIG) has driven significant advances in wearable electronics, advanced healthcare, and energy devices. However, achieving diverse functionalities and high‐performance for practical use requires integrating functional materials, which remains challenging due to poor synthesis results or complex chemical treatments. Herein, direct, seedless growth of transition‐metal‐oxide (MO) crystalline nanorods on LIG is demonstrated, even under lattice‐mismatch conditions, via a non‐epitaxial process. Ultrafast laser pyrolysis during LIG formation introduces nitrogen‐ and oxygen‐containing surface groups that facilitate the nucleation of MO during subsequent synthesis, enabling the selective growth of MO nanorods exclusively on LIG patterns without additional lattice‐matching or patterning steps. Through this non‐epitaxial growth, crystalline orthorhombic WO ₃ ·0.33 H ₂ O and β‐FeOOH nanorods are successfully synthesized on LIG micro‐patterns. As a proof‐of‐concept, LIG electrodes integrated with these crystalline MO nanorods are employed in all‐solid‐state micro‐supercapacitors, exhibiting significantly enhanced capacitive performance owing to the electrochemical reactivity of the MO nanorods, together with excellent mechanical and cyclic stability. Beyond this demonstration, the non‐epitaxial strategy offers a versatile route for harnessing the diverse functionalities of MO nanostructures, unlocking new possibilities in graphene‐based electronics.