Abstract
Nanocellulose is a promising new membrane material for fuel cells, with much lower cost and environmental impact compared with Nafion or Aquivion. It is mechanically strong, is an excellent hydrogen barrier and has reasonable proton conductivity.Here, sulfonation of cellulose nanofibers is performed to enhance the conductivity (up to 2 × 10− 3 S cm− 1) without compromising the membrane integrity, and fuel cells are fabricated with 30 µm-thick “paper” membranes. The hydrogen crossover current is two orders of magnitude lower than for Nafion fuel cells with equivalent thickness, but the power density is rather low.Spray-coating is used to deposit 8 µm-thick membranes directly onto the electrocatalyst layer, in a process analogous to 3D printing or additive manufacturing. The resulting paper fuel cell has high current density (> 0.8 A cm− 2) and power density (156 mW cm− 2) under standard measurement conditions (H2/air; 80°C; 95% RH; 0.1 MPa), attributed to decreased membrane resistance. The cost of the spray-painted cellulose membranes is calculated to be ~ 50 $ m− 2, which is much lower than that of Nafion, even without taking into consideration economies of scale. This new concept in electrochemical energy conversion paves the way for the mass production of affordable, recyclable fuel cells.Graphic abstract
Highlights
Polymer electrolyte fuel cells (PEFCs) are one technology helping us to move away from fossil fuels and towards a hydrogen economy, powered by renewable energy
The retention of the fibrous structure even after sulfonation is expected to contribute to mechanical stability of S-cellulose nanofibers (CNFs) membranes, as compared to cellulose nanocrystals (CNCs)
Sulfonated cellulose nanofiber (S-CNF) paper was investigated as a replacement for Nafion in fuel cells for the first time
Summary
Polymer electrolyte fuel cells (PEFCs) are one technology helping us to move away from fossil fuels and towards a hydrogen economy, powered by renewable energy. PEFCs fuelled by hydrogen have already been commercialized in stationary residential applications and as fuel cell vehicles (FCVs) in Japan (Sasaki et al 2016). PEFCs currently are far more expensive than conventional combustion engines or batteries, partly due to the high cost of the fuel cell stack (as well as the hydrogen storage system) (Sun et al 2010; Eberle et al 2012). This high cost hampers their widespread distribution, limiting their potential impact on CO2 and PM2.5 emissions.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
