Nanoarchitecture Of Co/Fe-N-C Electrocatalysts For Zn-Air Batteries

Zinc-air battery,which has a very high theoretical specific energy density(1218 Wh kg^-1),has been regarded as a new generation of energy storage devices and has received widespread attention.At the same time,with the rise of flexible wearable electronic devices and the urgent demand for underwater power batteries,high safety and reliability of Zinc-air batteries are expected to achieve curve overtaking in the above application fields.In this paper,transition metal and nitrogen-doped carbon-based catalysts were prepared by template method and alkaline polymer gel electrolyte was prepared by starch grafting acrylamide,and its application in zinc-air battery was realized under different conditions.First,we prepared a bifunctional catalyst（Co/Fe-N-C）with stacked carbon nanotubes and carbon nanosheets using low-cost sodium chloride as template and melamine as carbon and nitrogen sources.When the molar ratio of Co to Fe is 2:1,the catalyst has the best catalytic activity of ORR and OER,and itsΔE value is only 0.72 V.The practical application of Co/Fe-N-C catalyst in Zinc-air batteries shows high power density and specific discharge capacity,and can work stably for 180 h in constant current charge and discharge tests.Secondly,we have prepared an alkaline polymer gel electrolyte（S-PAM）with high electrolyte retention and ionic conductivity by grafting acrylamide onto starch to improve the contact between electrolyte and electrode,which greatly improved the contact between the electrolyte and the electrode.The flexible Zinc-Air battery based on this electrolyte not only has high working potential and cycle stability,but also shows good bending resistance and hammer impact performance and keeps stable operation,which confirms the feasibility of applying Co/Fe-N-C catalyst and S-PAM electrolyte in flexible Zinc-Air battery.Finally,we designed and assembled a zinc-air cell assisted by a large area of gas diffusion layer.We verified that the large area gas adsorption layer can adsorb oxygen in water.The Zinc-Air battery with the aid of a large area gas adsorption layer was discharged steadily at a current density of 1 m A cm^-2 for 70 h.In the process of constant current charge and discharge,the polarization potential of the battery was only half of that of the traditional Zinc-air battery and showed good stability.