Rational Design Of Porous Carbon-Based Oxygen Electrocatalysts For High-performance Rechargeable Zinc-Air Batteries

Heteroatom doped graphitic carbons with unique physicochemical properties,such as good electrical conductivity and stability,exhibit highly promising applications in electrocatalysis,Zinc-air batteries,and fuel cells.The rational design of carbon-based bifucntioanl oxygen electrocatalysts as alternatives for noble metal-based electrocatalysts is of importance for fabricating high-performance rechargable Zn-air batteries.Herein,we developed simple yet efficient apporches to desiging hereroatom doped carbon-based electrocatalysts in order to regulate their porous strcture and composition for both oxygen reduction and oxygen evolution reactions.The good bifunctional catalytic activities of the as-prepared electrocatalysts enable the fabrication of rechargeable Zn-air batteries with good performance:1.To reveal the effect of nitrogen doping on the electrocatalytic activity of porous carbon materials,porous carbon electrocatalysts have been prepared by a thermal bubbling of the mixed glucose,ammonium chloride and cyanuric acid as carbon and nitrogen sources at elevated temperatures.With the comparison of catalytic activities of porous carbon electrocatalysts prepared at different temperatures the electrocatalytic activity were investigated.2.Polyaniline spheres with porous structure were synthesized by interfacial polymerization and the subsequent thermal carbonization leads to the formation of porous carbon spheres with nitrogen and phosphorus co-doping.The combination of density functional theory(DFT)calculation and experimental results revealed that porous structure is helpful to expose the edges with nitrogen and phosphorus dopants for enhanced catalytic activity,thus improving performance of Zinc-air batteries.3.The cooperative self-assembly method was used to synthesize the organic-inorganic precursors via the coordination and electrostatic interaction of polyethyleneimine(PEI)with amino functional groups,cobalt ions,and sodium lignosulfonate(SLS).The pyrolysis of such precursors resulted in the formation of hollow CoO nanoparticles in the porous carbon matrix co-doped with nitrogen and sulfur.The obtained composite electrocatalyst exhibited good bifunctional catalytic activity for ORR and OER,which allowed the fabrication of high-performance Zn-air batteries.