Electrochemically exfoliated graphite as a highly efficient conductive additive for an anode in lithium‐ion batteries

Abstract

Abstract In this study, the electrochemical characteristics of an anode fabricated using exfoliated graphite (EG), which is mass‐produced using an electrochemical method, are evaluated to verify the potential of EG as a conductive additive. EG exhibits high electrical conductivity because of the sp2 bonding on the two‐dimensional plane; this conductivity provides a stable electrical pathway and promotes electron transfer in the anode. Furthermore, the small number of graphene layers in EG provide excellent mechanical properties (elastic modulus, tensile strength), which suppresses the volume expansion of the anode during lithiation; therefore, EG‐based anode exhibits high capacity retention and charge/discharge cycle stability. The EG with a large specific surface area improves energy density by decreasing the amount of the additive by more than 70% compared to conventional conductive additives and by simultaneously increasing the amount of the active material. The capacity of the electrode with 3.0 wt% EG reaches 376 mAh/g even after 200 cycles at 0.2 C and 99% of its initial reversible capacity. The rate performance of the electrode with 3.0 wt% EG was about 370 mAh/g at 5.0 C. These results confirm that EG can be used as a conductive additive to overcome the limitations of existing commercial conductive agents.

Keywords

• anodes
• conductive additives
• exfoliated graphene
• lithium‐ion batteries