A wide range (y = 0.05–0.33) of Co-doped LiCoyMn2–yO4 spinels were synthesized and electrochemically characterized. These Co-doped spinels showed improved specific capacity and capacity retention over pure spinels. Electrochemical impedance spectroscopy and the linear polarization resistance technique were used to determine the transport and electrochemical kinetic parameters of Co-doped spinels. The presence of Co in the spinel inhibits the passivation process occurring on the surface of the cathode. Also, Co increases the exchange current density and facilitates the charge-transfer reaction of the active material. The lower self-discharge observed for Co-doped spinels was attributed to their low surface areas. The cumulative capacity loss estimated for a pure spinel resulting from self-discharge in the first 30 h was 3 and 6 times larger than those estimated for Co-doped spinels with y = 0.05 and y = 0.16 in LiCoyMn2–yO4, respectively.
Journal of the Electrochemical Society, 1998, pages 807-815.
© The Electrochemical Society, Inc. 1998. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in the Journal of the Electrochemical Society.
Publisher's link: http://dx.doi.org/10.1149/1.1838349DOI: 10.1149/1.1838349