Electrochemical Properties of Li Metal Batteries with P(PEGMA)-Coated Lithium Trivanadate Cathode and Li Powder Anode

Abstract

Ionic conductive poly(poly(ethylene glycol) methyl ether methacrylate) (hereafter polymer) was coated onto a lithium trivanadate (LiV3O8) cathode by using an electrostatic spray deposition method in an effort to improve the ionic conductivity and prevent dissolution of vanadium into the electrolyte. The coating layer on the LiV3O8 electrode was identified by Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy. Polymer was uniformly coated on the LiV3O8 electrode with a thickness of about 40 nm. Lithium powder, synthesized by the droplet emulsion technique, was used as the anode. Electrochemical charge-discharge tests showed that the cell based on the polymer-coated LiV3O8 cell exhibited an initial specific capacity of 186 mAh/g and the capacity retentions of the polymer-coated LiV3O8 after 100cycles was 87%, which is far improved that of uncoated cell (65%). Also, the coated cell showed 81% of the capacity retention after 300 cycles at 2 C-rate. These results demonstrate that the polymer coating on LiV3O8 is effective for suppressing capacity fading at high C-rate.