Improvement of the Cycling Performance of LiNi_(0.6)Co_(0.2)Mn_(0.2)O2 Cathode Active Materials by a Dual-Conductive Polymer Coating

摘要

LiNi_(0.6)Co_(0.2)Mn_(0.2)O2 cathode materials were surface-modified by coating with a dual conductive poly (3,4- ethylenedioxythiophene)- co-poly (ethylene glycol) (PEDOT-co-PEG) copolymer, and their resulting electrochemical properties were investigated. The surface-modified LiNi_(0.6)Co_(0.2)Mn_(0.2)O2 cathode material exhibited a high discharge capacity and good high rate performance due to enhanced transport of Li~+ ions as well as electrons. The presence of a protective conducting polymer layer formed on the cathode also suppressed the growth of a resistive layer and inhibited the dissolution of transition metals from the active cathode materials, which resulted in more stable cycling characteristics than the pristine LiNi_(0.6)Co_(0.2)Mn_(0.2)O2 cathode material at 55 °C.