SINGLE-, DOUBLE- AND MULTI-WALLED CARBON NANOTUBES AS ELECTRICALLY CONDUCTIVE ADDITIVES IN LITHIUM-ION BATTERY CATHODES

Abstract

The paper presents a comparative study of the characteristics of lithium iron phosphate positive electrodes with various types of commercially available carbon nanotubes – single-walled (SWCNT), double-walled (DWCNT) and multi-walled (MWCNT). Electrochemical characteristics of the cathode materials were investigated using electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements. Cyclic stability at various current densities was estimated. The best electrochemical characteristics are exhibited by cathode materials with SWCNT (advantage over DWCNT at discharge rates higher than 10C) and DWCNT (advantage over SWCNT during prolonged cycling). During cycling at a current density of 1C, the greatest loss of capacity was demonstrated by the MWCNT-based electrode. At the same time, the electrodes with SWCNT and DWCNT demonstrated satisfactory capacity retention after 50 charge/discharge cycles: over 94 and over 98%, respectively.