氮化钛纳米颗粒作为锂氧电池正极催化剂的电化学行为

Electrochemical behavior of TiN nanoparticles as the cathode catalyst for lithium-oxygen batteries

采用直流电弧等离子体法在氮气和氢气气氛下制备氮化钛纳米颗粒,作为锂氧电池正极催化剂。通过透射电镜(TEM)、X射线衍射(XRD)等对材料进行微观结构表征,结果显示纳米氮化钛呈现立方结构,晶粒尺寸为30.00～60.00 nm,晶化程度良好。氮化钛纳米颗粒作为锂氧电池正极催化剂,电流密度为50 mA/g时,放电比容量达到3 037 mAh/g;在定容500 mAh/g,电流密度为75 mA/g时,电池可稳定循环,能量效率维持在62%左右。此外,充放电循环后电极片的XRD、SEM结果证明锂氧电池的主要反应为过氧化锂的生成与分解。

The titanium nitride nanoparticles were prepared by DC arc-discharge method and served as the cathode catalyst for lithium-oxygen batteries. Various analytical methods, including X-ray diffraction, Transmission Electron Microscopy and etc., are used to characterize the microstructure and morphology of the TiN nanoparticles. The results show that the TiN nanoparticles had a cubic structure with good crystallinity. Its grain size varied from 30 to 60 nm. The rotating disk electrode(RDE) test shows that the TiN nanoparticles had dual catalytic properties of both oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). As the cathode catalyst for the lithium-oxygen batteries, the TiN electrode delivered 3 037 mAh/g discharge specific capacity at a current density of 50 mA/g. The energy efficiency of the battery could maintain in 62% at a limited capacity of 500 mAh/g and a current density of 75 mA/g. Furthermore, XRD and SEM results of the cycled TiN electrode show that the main reaction of lithium-oxygen batteries was the formation and decomposition of lithium peroxide.