Preparation Of Transition Metal Sulfide/porous Carbon Composite Material And Its Application In Zinc-air Battery

With the gradual exhaustion of non-renewable resources such as fossil,and the increasing seriousness of environmental pollution,the development of energy storage devices has also received increasing attention.Zinc-Air Battery?ZAB?is one of the most promising energy storage devices.Oxygen reduction reaction?ORR?and oxygen precipitation reaction?OER?are two important reactions in zinc air battery,and the key to affect these two reactions is catalyst.The development of low-cost,highly active dual-function electrocatalysts is very important.Among them,porous carbon materials and transition metal sulfides exhibit excellent electrochemical and physical properties,and the use of these properties for design of bifunctional electrocatalyst will effectively improve the ORR/OER performance of the catalyst.Based on this,the design and preparation of Zn-air battery energy storage device based on porous carbon/transition metal sulfur compounds as electrocatalysts are studied.Research results and contents are as follows:?1?Herein,based on glucose as the carbon source and SiO₂ as the hard template,we prepared N,S co-doped porous carbon?NSC?.Due to the large specific surface area of NSC,Fe₇S₈ nanoparticles can be uniformly supported on NSC by adsorption and high temperature annealing.The obtained Fe₇S₈/NSC is the 3-dimensional interconnection network structure,and shows remarkable oxygen electrocatalytic activity,in terms of superior ORR activity to commercial Pt/C as well as comparable OER capability to RuO₂.Besides,when evaluated as the cathode catalyst for a homemade ZAB,Fe₇S₈/NSC also displays a superior peak power density of 135mA·cm^-2 and high cycling stability over 65 hours?195 cycles?at a current density of10 mA cm^-2.?2?Rational design of efficient,cost-effective and robust bifunctional oxygen electrocatalysts for oxygen reduction reaction?ORR?and oxygen evolution reaction?OER?is of vital significance to the large-scale application of rechargeable Zn-air battery?ZAB?.Herein,we demonstrate a novel and simple method for preparing nitrogen and sulfur co-doped interconnected carbon nanofiber network?NSCF?from fish bone,which is a carrier for improving catalytic activity.In order to further improve the bifunctional catalytic activity,we composited it with?Fe,Co,Ni?₉S₈ and CoS₂ nanoparticles.It was found that?Fe,Co,Ni?₉S₈/NSCFs are more suitable as cathode materials for batteries.The?Fe,Co,Ni?₉S₈/NSCFs shows large specific surface area(750 m² g^-1),well-defined interconnected nanofibers network structure with high conductivity,synergistic chemical coupling effects between?Fe,Co,Ni?₉S₈and NSCFs with doped heteroatoms of N and S.As expected,in alkaline medium,excellent catalytic activity and outstanding durability toward both ORR and OER are obtained.Moreover,the homemade all-solid-state ZAB based on?Fe,Co,Ni?₉S₈/NSCFs displays outstanding battery capacity and power density together with excellent durability and flexibility.As an additional advance,a digital display screen powered by?Fe,Co,Ni?₉S₈/NSCFs-based rechargeable ZAB works steadily at twisted,extruded,combusting,and punctured states,making our bifunctional electrocatalysts attractive for wearable energy storage applications.