Liquid Metal/Wood Anisotropic Conductors for Flexible and Recyclable Electronics

Abstract Next‐generation electronics requiring high performance, recyclability, and low environmental impact are still in its infancy because of limited design strategies and materials. Herein, a facile approach for constructing liquid metal/wood anisotropic (LMWA) conductors via integration of gallium based LMs and delignified flexible wood (DF‐wood) is reported. Using a delignification treatment and a subsequent LM transfer process with patterns, a rigid and electrically insulating wood slice is converted into a flexible wood‐based LM conductor while retaining its original hierarchical porous structure. The LMWA conductor demonstrates a remarkable anisotropic electrical conductivity ( σ z / σ x ) on the order of 10 8 . Subsequently, the LMWA conductors are successfully applied as flexible four‐channel tactile sensor, which exhibits excellent tactile sensitivity. Moreover, by immersing in a deep eutectic solvent (DES) composed of choline chloride with oxalic acid to dissolve the LM circuit, recycling of the LM is achieved with efficiency up to 96%. This is the first time that a DES is used to recycle LM, leading to increased economic and environmental viability of these sustainable electronics. The present LMWA conductors, which have the potential for a scalable and feasible fabrication process, substantially extend the scope of next‐generation electronics toward flexible and recyclable systems.