Construction Of Nickel-based Transition Metal Nitride Materials And Their Application In Rechargeable Zinc-air Battery

Developing clean energy for sustainable development is pivotal to solve the energy crisis and environmental issues.Zinc-air batteries,as one of the representative of energy storage and conversion devices,have been extensively studied owing to their low cost,high safety performance,and easy miniaturization.However,the power-density of zinc-air batteries is severely constrained by the slow dynamics of ORR/OER on the air cathode.Currently,the noble metal-based catalyst（Pt,Ir,Ru）is deemed as the state-of-the-art benchmark catalyst for ORR/OER,but the high prices and poor bifunctional catalytic durability of noble-metal-based catalysts have significantly restricted their large-scare commercial application.Therefore,developing high-performance,low-cost,and high-stability bifunctional electrocatalysts to accelerate the ORR/OER is crucial for high-performance ORR/OER electrocatalysts to satisfy the needs of Zn-air batteries.In this paper,based on the physicochemical properties of transition metal nitrides,introducing heteroatoms and constructing heterostructure are utilized to optimize the electronic structure of transition metal nitride materials,improving their electrocatalytic performance,and broaden their application range in zinc-air batteries.The main contents are shown below:（1）Based on the versatile tunability of incorporated di-and tri-valent metal ions during the synthesize of layer double（multi-metal）hydroxide（LD（M）H）,Zn-doped Ni₃Fe N/nitrogen-doped graphene electrocatalytic materials are synthesized by rapid vacuum calcination and post thermal ammonolysis.The electronic interaction between the inserted Zn²⁺and Ni₃Fe N can change the electronic state on the surface of the material and optimize the adsorption/desorption characteristics of the intermediate,therefore,generating more catalytic active sites towards the ORR/OER reaction.The Zn-Ni₃Fe N/NG exhibits high ORR catalytic activity(E_1/2=0.86 V)and OER catalytic activity(E_j10=1.60 V),and theΔE value is 0.74 V.In addition,zinc-air battery with Zn-Ni₃Fe N/NG as the air cathode shows an excellent cycle life and a high-power density.（2）Based on the"3d electron synergistic effect",heterojunctions（Ni₄N/VN-NG）composed by early transition metal（V）and late transition metals（Ni）are synthesized by thermal aminolysis Ni V-LDH/GO/g-C₃N₄ precursor.Thanks to the electron coupling of Ni₄N and VN,the heterojunction interface can promote interfacial charge transfer between the different components and enhance the catalytic activity.Also,nitrogen-doped graphene can prevent the corrosion and aggregation of transition metal nanoparticles during the electrocatalytic reaction.The Ni₄N/VN-NG shows an excellent ORR catalytic activity(E_1/2=0.87 V)and OER catalytic activity(E_j10=1.62V),and theΔE value of Ni₄N/VN-NG is 0.75 V.Besides,the zinc-air battery with Ni₄N/VN-NG as the air cathode exhibits an excellent cycle life and a high-power density.（3）Inspired by the previous works,the Ni₃Fe N/VN-NG materials are synthesized to combine the advantages of Ni₃Fe N and heterostructure to enhance the catalytic performance of the electrocatalysts.Thanks to the electronic synergy effect between Ni₃Fe N and VN,Ni₃Fe N/VN heterostructure can generate abundant catalytic active sites on the heterogeneous interface.Benefiting by the excellent catalytic performance of Ni₃Fe N/VN and the strong interaction between the nanoparticles and the nitrogen-doped graphene substrate material,the Ni₃Fe N/VN-NG electrocatalyst exhibits an excellent ORR(E_1/2=0.87 V)and OER(E_j10=1.56 V)bifunctional electrocatalytic activity,and itsΔE value is 0.69 V.what is more,the zinc-air battery with Ni₃Fe N/VN-NG as the air cathode shows charge-discharge cycle stability of more than 200 h and a power density of up to 168 m W cm^–2 under practical operating conditions.