Linking Renewable Cellulose Nanocrystal into Lightweight and Highly Elastic Carbon Aerogel

Compressible and elastic carbon aerogels with low density, excellent conductivity, high porosity, and chemical stability have attracted much attention in wearable energy storage and sensing devices. However, the mechanical performances of current carbon aerogels are usually limited due to undesirable structural engineering. Herein, an effective and sustainable route is proposed to fabricate a lightweight yet highly elastic carbon aerogel from a renewable nanounit. To realize this aim, mechanically strong cellulose nanocrystal (CNC) serves as the structural unit, while konjac glucomannan (KGM) links CNCs into continuous and orientally aligned layers with a wavy shape. The lamellar architecture and the interaction among CNC and KGM give rise to a lightweight carbon aerogel with ultrahigh structural stability and outstanding mechanical performance that is superior to those of graphene and carbon nanotube (CNT)-based carbon aerogels. Specifically, it can maintain 100% height and 90.6% stress after 10,000 cycles at 50% compression strain. It even can withstand a high compression strain of 90% for 1000 cycles with negligible structure deformation. The unique structure, outstanding mechanical performance, and highly sensitive current response enable the carbon aerogel to accurately detect human biosignals.