Effect of Carbon Content on Electrochemical Performance of LiFePO₄/C Thin Film Cathodes

摘要

Submicron-sized hydrothermal-grown LiFePO4 particles were added into sucrose-water solutionfollowed with annealing in 600 for 3 hours in nitrogen to form thin, binder-free and high energyLiFePO4/C composite film cathodes and the effects of carbon content on the microstructure andelectrochemical properties of such films were investigated. Carbon from sucrose pyrolysis served asboth conducting additive and adhesion binder. The structure characters of the LiFePO4/C films wereanalyzed by XRD, SEM, BET, etc. and the electrochemical properties of the films were studied. It wasfound that 23wt% carbon content could effectively improve the conductivity of the LiFePO4 materialand keep the films intact. The coherent LiFePO4/C composite film cathode is capable of delivering-1 -1 -1 lithium-ion intercalation capacity of 141 mAh g and 131 mAh g at current density of 85 mA g [0.5-1 C] and 170 mA g [1 C], respectively, with a good cyclic stability.