Background: High performance carbon papers made from renewable carbon materials
have the potential to boost the development of electrochemical energy technologies.
Method: Free-standing and binder-free biocarbon papers have been successfully prepared through a
simple one-step carbonization of thin sheets of pre-densified balsa wood. They exhibit an electrical
conductivity of 0.16 S/cm and a carbon content higher than 95 wt%. The Brunauer-Emmett-Teller
(BET) studies show that the biocarbon possesses a hierarchical porous structure characteristic of approximately
72% mesopores and 28% micropores with an average pore size of approximately 5.1 nm.
On the surfaces of biocarbon papers, several functional groups associated with C-O, C=C, C=O, and
N-O bonds were detected by the Fourier-transform infrared spectroscopy (FTIR) method. The X-ray
diffraction and Raman studies show that the crystalline microstructures of the biocarbon are characterized
by shorter stacks and larger atomic layer spacing compared to regular amorphous carbons.
Results: A supercapacitor comprising of two biocarbon paper electrodes exhibited excellent highrate
performance in sulfuric acid electrolyte, signaled by a rectangular current-voltage response
even at scan rates higher than 10 V/s. Furthermore, no obvious performance decay was observed
upon 20000 successive potential cycles. The results above suggest that the balsa-wood derived bio
carbon papers could be a new class of promising electrodes for electrochemical applications.