Toward uniform and ultrathin carbon layer coating on lithium iron phosphate using liquid carbon dioxide for enhanced electrochemical performance

Abstract

In this communication, uniform and ultrathin carbon coating on LiFePO4 (LFP) particles are performed using liquid carbon dioxide (l-CO2)-based free-meniscus coating. The uniform and conformal coverage of the carbon layer on LFP with a thickness of 33 nm, and a uniform distribution of carbon on the entire surface of the LFP particle are confirmed. The carbon-coated LFP (C-LFP) with a carbon content of 1.9 wt.% obtained using l-CO2-based coating exhibits a discharge capacity of 169 mAh g(-1) at 0.1 C and 71 mAh g(-1) at 30 C, while much lower discharge capacity of 146 mAh g(-1). at 0.1 C and 17 mAh g(-1) at 30 C is observed when C-LFP with an optimized carbon content of 6.0 wt.% is prepared using conventional aqueous-based coating. Crown Copyright(C) 2014 Published by Elsevier B.V. All rights reserved.