A LiCoO2 cathode modified by plasma chemical vapor deposition for higher voltage performance

Surface modification of the electrode dramatically improved the performance of a LiCoO2 electrode charged to 4.6 V.A diamondlike carbon thin film was deposited uniformly on the electrode surface using de plasma chemical vapor deposition. This surface treatment suppressed electrolyte decomposition du ring the charge process. When a coin-type cell using this electrode was cha rged to 4.6 V, the discharge capacity in the first cycle was 212 mAh/g and the charge-discharge efficiency was over 90% through five cycles. This trea tment suggests a new approach to the development of cathodes for lithium-io n secondary batteries. (C) 2000 The Electrochemical Society. S0013-4651(99) 09-083-7. All rights reserved.