Tendon-Inspired Multiscale Bamboo-Based Ionic Gel for High-Performance Flexible Energy Conversion

Naturally rigid cellulose is an ideal mechanical reinforcement for ionogels, but its presence often hinders the migration of gel ions, affecting its application in flexible self-powered electronics. Inspired by tendon hierarchy, we propose a three-step strategy (delignification, ionic-liquid induction, and UV-crosslinking) to reconstruct bamboo across molecular-nano-macro scales into a multiscale bamboo ionic gel with a hard-core/soft-shell architecture. Density functional theory calculations reveal carboxyl–hydroxyl–ion mediated triple hydrogen bonds significantly increase the interfacial binding between bamboo fiber and gel matrix. Consequently, the gel achieves a tensile strength of 100 MPa, a toughness of 17.25 MJ m⁻³ at 48% strain, and only ∼ 1% hysteresis variation over 1000 cycles. Furthermore, bamboo-fiber skeleton increase conductivity (1.43 mS cm⁻¹) by 472% compared to pure ionogel. It can be used as an electrode in a triboelectric device, generating an open-circuit voltage of 366 V and a peak power density of 99.98 µW cm⁻², enabling highly sensitive self-powered joint/gait monitoring. By incorporating machine learning, gel-based triboelectric devices can perform human-computer interaction tasks with up to 99% accuracy. This study successfully designed an ionogel with both high-mechanical strength and efficient ion transport capability using a biomimetic strategy, demonstrating its broad potential in flexible self-powered devices.