Preparation of Novel Biodegradable Cellulose Nanocrystal Proton Exchange Membranes for Direct Methanol Fuel-Cell Applications

The material processing procedure of cellulose nanocrystals (CNCs) was investigated for use as a proton exchange membrane (PEM) of direct methanol fuel cells (DMFCs). The CNCs were prepared from pulp via the sulfuric acid hydrolysis homogenization method. Novel biodegradable and environmentally friendly PEMs with good proton conductivity and mechanical properties were successfully prepared by grafting cytidine monophosphate, taurine, and cysteine onto CNC backbones. The DMFC operation test demonstrated that the modified films had a good power output performance and lower methanol permeability comparable to those of the available commercial membrane, which was nonbiodegradable and involved toxic fluorination. Their high performance and environmental friendliness indicated that the modified films might have potential applications in DMFCs.