Comparisons of graphite and spinel Li1.33Ti1.67O4 as anode materials for rechargeable lithium-ion batteries

The aim of this work was to compare the electrochemical behaviors and safety performance of graphite and the lithium titanate spinel Li1.33Ti1.67O4 with half-cells versus Li metal. Their electrochemical properties in 1 M LiPF6/EC + DEC (1:1 w/w) or 1 M LiPF6/PC + DEC (1:1 w/w) at room and elevated temperatures (30 and 60 degrees C) have been studied using galvanostatic cycling. At 30 degrees C graphite has higher reversible capacity than Li1.33Ti1.67O4 when using the LiPF6/EC + DEC as electrolyte. At 60 degrees C graphite declines in cell capacity yet Li1.33Ti1.67O4 remains almost unchanged. In a propylene carbonate (PC) containing electrolyte, graphite electrode exfoliates and loses its mechanical integrity while Li1.33Ti1.67O4 electrode is very stable. An accelerating rate calorimeter (ARC) and microcalorimeter have been used to compare the thermal stability of lithiated lithium titanate spinel and graphite. Results show that Li1.33Ti1.67O4 may be used as an alternative anode material offering good battery performance and higher safety. (c) 2005 Elsevier Ltd. All rights reserved.