Single Wall Carbon Nanotube – LiCoO2 Lithium Ion Batteries

Abstract

ABSTRACTThe electrochemical cycling performance of high purity single wall carbon nanotube (SWCNT) paper electrodes has been measured for a series of electrolyte solvent compositions. The effects of varying the galvanostatic charge rate and cycling temperature on lithium ion capacity have been evaluated between 25-100 °C. The measured reversible lithium ion capacities for SWCNT anodes range from 600-1000 mAh/g for a 1M LiPF6 electrolyte, depending on solvent composition and cycling temperature. The solid-electrolyte-interface (SEI) formation and first cycle charge loss are also shown to vary dramatically with carbonate solvent selection and illustrate the importance of solvent alkyl chain length and polarity on SWCNT capacity. SWCNT anodes have also been incorporated into full battery designs using LiCoO2 cathode composites. An electrochemical pre-lithiation sequence, prior to battery assembly, has been developed to mitigate the first cycle charge loss of SWCNT anodes. The pre-lithiated SWCNT anodes show reversible cycling at varying charge rates and depths of discharge with the cathode system. The summary of data shows that the structural integrity of individual SWCNTs is preserved after cycling, and that free-standing SWCNT paper electrodes represent an attractive material for lithium ion batteries.