Ni_(3)FeN anchored on porous carbon as electrocatalyst for advanced Li-S batteries

Lithium-sulfur(Li-S)battery is one of the newgeneration energy storage systems with great potential.However,the development of Li-S battery now is hampered by the shuttle effect and depressed redox kinetics.Herein,we report a composite of Ni_(3)FeN nanoparticles anchored in grid-like porous carbon(PC)spheres as an effective cathode electrocatalyst with simultaneous polysulfide trapping and rapid polysulfides conversion in Li-S battery.The multi-cavity structure of PC with high-efficiency encapsulation ability can significantly improve sulfur utilization and confinement.Furthermore,Ni_(3)FeN nanoparticles embedded in PC cavities render highly active catalytic sites to promote the redox conversion of solvated poly sulfide,as revealed by the electrochemical results.Moreover,the catalytic mechanism is further analyzed through density functional theory calculations and in-situ Fourier transform infrared analysis.As a result,PC@Ni_(3)FeN@S cathode delivers an outstanding capacity of 1294mAh·g^(-1)at 0.1C and low decay rates of 0.10%per cycle over 500 cycles at 0.5C.

Mesoporous Ternary Nitrides of Earth?Abundant Metals as Oxygen Evolution Electrocatalyst

As sustainable energy becomes a major concern for modern society,renewable and clean energy systems need highly active,stable,and low-cost catalysts for the oxygen evolution reaction(OER).Mesoporous materials offer an attractive route for generating efficient electrocatalysts with high mass transport capabilities.Herein,we report an efficient hard templating pathway to design and synthesize three-dimensional(3-D)mesoporous ternary nickel iron nitride(Ni3FeN).The as-synthesized electrocatalyst shows good OER performance in an alkaline solution with low overpotential(259 mV)and a small Tafel slope(54 mV dec?1),giving superior performance to IrO2 and RuO2 catalysts.The highly active contact area,the hierarchical porosity,and the synergistic effect of bimetal atoms contributed to the improved electrocatalytic performance toward OER.In a practical rechargeable Zn–air battery,mesoporous Ni3FeN is also shown to deliver a lower charging voltage and longer lifetime than RuO2.This work opens up a new promising approach to synthesize active OER electrocatalysts for energy-related devices.