Enhanced oxygen reduction reaction for Zn-air battery at defective carbon fibers derived from seaweed polysaccharide

• Published in: Applied catalysis. B, Environmental Vol. 301; p. 120785
• Main Authors: Zhao, Xiaoliang, Yu, Xuezheng, Xin, Shishan, Chen, Shuai, Bao, Chaosheng, Xu, Wenqing, Xue, Jingfei, Hui, Bin, Zhang, Jianwei, She, Xilin, Yang, Dongjiang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2022; Elsevier BV
• Subjects: Algae; Batteries; Carbon; Carbon fibers; Catalysts; Catalytic activity; Chemical reduction; Defective carbon fiber; Defects; Density functional theory; Doping; Electrocatalysts; Energy levels; Fibers; Hybridization; Metal air batteries; Oxygen; Oxygen atoms; Oxygen reduction reaction; Oxygen reduction reactions; Polysaccharides; Seaweed polysaccharide; Seaweeds; Zinc-air batteries; Zinc-oxygen batteries; Defective carbon fiber; Zinc-air batteries; Seaweed polysaccharide; Oxygen reduction reaction
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120785

Carbon fibers with intrinsic carbon defects (D-CFs) were fabricated through heteroatoms doping and de-doping using seaweed polysaccharide as the precursor. When evaluated as oxygen reduction reaction (ORR) electrocatalyst, D-CFs display an initial potential of 0.92 V (vs. RHE) and a limiting diffusion current density of 5.38 mA·cm−2 in KOH electrolyte (0.1 M). The high peak power density of zinc-air batteries (ZABs) assembled by D-CFs is 238 mW·cm−2, that is much better than commercial Pt/C (154 mW·cm−2). In the light of density functional theory (DFT) results, enriched electrons in defects make the hybridization energy levels of active defective sites and adsorbed oxygen atoms rise to Fermi level, indicating that O2 molecules are inclined to be adsorbed onto defective carbon atoms. Therefore, abundant renewable seaweed sources, together with the excellent ORR catalytic activity, make D-CFs as the substitute of Pt/C catalyst for large-scale application of ZABs. Intrinsic carbon defects at carbon fibers change the electronic structure of carbon atoms. And then the enriched electrons in defects make the hybridization energy levels of active defective sites and adsorbed oxygen atoms rise to Fermi level. This results in that the O2 molecules are inclined to be adsorbed onto the defective carbon atoms. Thus, the defective carbon fibers reveal excellent performance in zinc-air battery, whose peak power density is as high as 238 mW∙cm−2. [Display omitted] •Carbon fibers with intrinsic defects were fabricated from marine biomass alginate.•Hybridization energy levels of defective sites and adsorbed oxygen atoms rise to Fermi level.•Defective carbon fibers reveal prominent performance of ORR and ZABs application.•The peak power density of defective carbon fibers is as high as 238 mW∙cm−2.