Enhancing electromechanical conversion and motion-monitoring application of pore-oriented cellulose nanocrystal/agarose aerogel modified with flexible heterojunction structures

Oriented-porous cellulose nanocrystal (CNC)-based aerogels excel in directional energy conversion but face reduced toughness, and triboelectric performance bottlenecks owing to the absence of electron acceptors. In this work, we crosslinked quaternary ammonium CNC with another flexible carboxymethyl agarose (AG-), via borate dynamic bonds, exploiting the electron-accepting traits of boron and electrophilic modifications to boost the mechanical and triboelectric performance of aerogels. These results demonstrate that the compressive resilience and modulus of CNC/AG aerogel are improved up to 70.79 % (after 10-cycle 20 % strain) and 18.77 kPa attributing to the borate cross-linking network and oriented structure. Furthermore, the electromechanical response sensitivity and output energy density of the CNC/AG aerogel increased by 6.06 times (to 7.51 V/Hz) and 28.3 times (to 1.87 W/m²), respectively. The structure characteristics of the CNC/AG aerogel reveal that the oriented structure and heterojunction of the CNC/AG aerogel with electron transfer pathways reduce dielectric losses. The COMSOL simulation also show that oriented pores increase the polarization and charge density of the CNC/AG aerogel, thereby improving the electromechanical conversion efficiency. This work offers a synergistic approach for toughening aerogels and generating heterojunctions via flexible modification, presenting significant potential for smart devices with energy-collection ability.