Electrochemical behavior of carbon-coated silicon monoxide electrode with chromium coating in rechargeable lithium cell

Abstract

The effects of Cr coating are studied with respect to improving the electrochemical characteristics of carbon-coated silicon monoxide anodes in rechargeable Li cells. The Cr coating is applied by ion beam sputtering. Analyses of the coating are carried out by EDX, SEM, TEM, and EPMA. A coin cell (CR2032) with a carbon-coated SiOx anode coated with Cr and a lithium cobalt oxide (LCO) cathode is assembled in an argon-filled glove box. The charged capacity of the Cr-coated SiOx-C/LCO cell is 1127 mAh g(-1) in the 1st cycle at 0.1 C, while that of the uncoated SiOx-C/LCO cell is 956 mAh g(-1). In addition, the Cr-coated SiOx-C/LCO cell has a discharged capacity of 733 mAh g(-1), which is higher than that of the uncoated cell (635 mAh g(-1)). Furthermore, the discharge capacity retention ratio (100th:2nd) of the Cr-coated cell is 75% while that of the uncoated cell is 69%. The rate capability of the Cr-coated cell is superior to that of the uncoated cell. Cr has good electrical conductivity, enabling more Li ions to be stored in the Cr-coated cell than in the uncoated cell. Investigations into the improved electrochemical characteristics are carried out through the analyses of impedance, voltage profile, and cycle data. (C) 2013 Elsevier B.V. All rights reserved.