Biopolymer-Derived Carbon Materials for Wearable Electronics.

Advanced carbon materials are widely utilized in wearable electronics. Nevertheless, the production of carbon materials from fossil-based sources raised concerns regarding their non-renewability, high energy consumption, and the consequent greenhouse gas emissions. Biopolymers, readily available in nature, offer a promising and eco-friendly alternative as a carbon source, enabling the sustainable production of carbon materials for wearable electronics. This review aims to discuss the carbonization mechanisms, carbonization techniques, and processes, as well as the diverse applications of biopolymer-derived carbon materials (BioCMs) in wearable electronics. First, the characteristics of four representative biopolymers, including cellulose, lignin, chitin, and silk fibroin, and their carbonization processes are discussed. Then, typical carbonization techniques, including pyrolysis carbonization, laser-induced carbonization, Joule heating carbonization, hydrothermal transformation, and salt encapsulation carbonization are discussed. The influence of the processes on the morphology and properties of the resultant BioCMs are summarized. Subsequently, applications of BioCMs in wearable devices, including physical sensors, chemical sensors, energy devices, and display devices are discussed. Finally, the challenges currently facing the field and the future opportunities are discussed.