Title N/S-doped hierarchical porous bamboo carbon fibers with
ultra-large surface area and highly exposed active sites for flexible
zinc-air battery
Abstract
Facile mass transport channel and accessible active sites is crucial for
binder-free air electrode catalysts in rechargeable flexible zinc-air
battery (ZAB). Herein, a ZnS/NH3 dual-assisted pyrolysis strategy is
proposed to prepare N/S-doped hierarchical porous bamboo carbon cloth
(HP-NS-BCC) as binder-free air electrode catalyst for ZAB. BCC fabric
with abundant micropores is firstly used as flexible carbon support to
facilitate the heteroatom-doping and construct the hierarchical porous
structure. ZnS nanospheres and NH3 activization together facilitate the
electronic modulation of carbon matrix by N/S-doping and optimize the
macro/meso/micropores structure of carbon fibers. Benefiting from the
highly-exposed N/S-induced sites with enhanced intrinsic activity, the
optimized mass transport of biocarbon fibers, as well as the ultra-large
specific surface area of 2436.1 m2 g-1, the resultant HP-NS-BCC catalyst
exhibits improved kinetics for oxygen reduction/evolution reaction. When
applied to rechargeable aqueous ZABs, it achieves a high open-circuit
voltage of 1.516 V and a significant peak power density of 249.1 mW
cm−2. As binder-free air electrode catalyst, the flexible ZAB also
displays stable cycling over 500 cycles with a minimal voltage gap of
0.42 V, showcasing promising applications in flexible electronic
devices.