Lithium bis(oxalato)borate (LiBOB) was tested as an additive in propylene carbonate (PC)-rich electrolytes that uses LiPF6 as the conductive solute. At as low as 5% molar LiBOB showed a distinctive additive effect, i.e., its participation in the initial surface chemistry on graphitic anode surface effectively prevented exfoliation. This property of LiBOB provides an opportunity of formulating PC-rich electrolytes with improvements in rate capabilities and performances at both high and low temperatures, as compared with the electrolytes based on LiPF6 or LiBOB as the sole electrolyte solute. (c) 2005 The Electrochemical Society.