Enhancing rate and stability performance of O3-type NiFeMnTi-based layered oxides via Sb/Co dual-doping

Abstract

O3-type layered metal oxides have been consider as a highly suitable cathode materials for Na-ion batteries (SIBs) due to their distinct advantages of high capacity, simple synthesis and affordable price. Nonetheless, the rapid capacity attenuation and the sluggish Na+ diffusion kinetic seriously impede their practical application. Herein, a dual-doping strategy of incorporating Stibium (Sb) and cobalt (Co) elements to a quaternary oxide cathode material (Na(Ni0.3Fe0.2Mn0.5)0.9Ti0.1O2) was proposed to further ameliorate the rate capability and the cycle stability. Because of the enlarged Na and TM interlayer spacing, Sb/Co dual-doping is verified to provide a higher Na+ diffusion rate and a more stable structure. Furthermore, Co doping is found to inhibit the formation of Ni2O3 and Na0.7MnO2 impurities triggered by Sb doping. The modified Na(Ni0.3Fe0.2Mn0.5)0.8Ti0.1Sb0.05Co0.05O2 electrode represents a high discharge specific capacity of 171.6 mAh g-1 at 0.1C within the voltage range from 2.0 V to 4.3 V, and an excellent rate capability of 82.0 mAh g-1 at 5C. More significantly, it shows a splendid capacity retention of 74.69 % over 300 cycles at 1C.