Enhanced Cycle Stability of Li_(1.2)Ni_(0.13)Mn_(0.54)Co_(0.13)O2 Cathode with Sodium Oxalyldifluoroborate Electrolyte Salt for Hybrid Li-Na Ion Battery

摘要

Sodium oxalyldifluoroborate(NaODFB)electrolyte is,for the first time,examined as the electrolyte for a hybrid Li-Na ion battery.The solvent is propylene carbonate(PC)in this report.Li_(1.2)Ni_(0.13)Mn_(0.54)Co_(0.13)O2(LNMCO)cathode exhibits better electrochemical performances in the NaODFB/PC electrolyte than those in the NaClO4/PC.The discharge capacity of LNMCO cathode shows a slight decrease from 202 mAhg~(-1)at the 10th cycle to 186 mAhg~(-1)at the 50th cycle in the NaODFB/PC,which is much better than that in the NaClO4/PC with a dramatically decreases from 190 mAhg~(-1)at the 27th cycle to 76 mAhg~(-1)at the 50th cycle.Moreover,in the NaODFB/PC,the LNMCO cathode attains a high discharge capacity of 151 mAhg~(-1)at the 200th cycle even at 0.5 C.The better reversible cycling performance of the LNMCO cathode in the NaODFB/PC is believed to be the formation of a more stable cathode solid electrode interphase based on scanning electron microscopy and X-ray photoelectron spectroscopy.