3D Spatial Combination of CN Vacancy-Mediated NiFe-PBA with N-Doped Carbon Nanofibers Network Toward Free-Standing Bifunctional Electrode for Zn-Air Batteries.

ABSTRACT: Constructing flexible free-standing electrodes with efficient bifunctional performance is significant for improving the performance of flexible Zinc-air batteries. Herein, a flexible free-standing bifunctional electrode (N₂ -NiFe-PBA/NCF/CC-60) is constructed by the 3D spatial combination of CN vacancy-mediated NiFe Prussian Blue Analogue (NiFe-PBA) and N-doped carbon nanofibers (NCF) rooted on carbon cloth (CC). The in situ formed CN vacancies by N₂ -plasma activation tune the local coordination environment and electronic structure of Ni-Fe active sites in NiFe-PBA, thus improving the oxygen evolution reaction (OER) catalytic intrinsic activity, and restraining the loss of Fe element during OER process. The combination of NiFe-PBA and NCF presents a 3D interworking network structure, which exhibits a large specific surface and excellent electrical conductivity, thus guaranteeing sufficient, stable, and efficient oxygen reduction reaction (ORR)/OER active sites. Therefore, the N₂ -NiFe-PBA/NCF/CC-60 electrode delivers high-efficiency OER activity with a low overpotential (270 mV at 50 mA cm^-2 ) and excellent ORR performance with a positive potential of 0.89 V at 5 mA cm^-2 . The N₂ -NiFe-PBA/NCF/CC-60 based Zn-air batteries display outstanding discharge/charge stability for 2000 cycles. Meanwhile, the corresponding flexible Zn-air batteries with satisfactory mechanical properties exhibit a low voltage gap of 0.52 V at 1.0 mA cm^-2 .

SUBMITTER: Lai C 

PROVIDER: S-EPMC9008428 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature