▎ 摘　　要

The energy density of electrochemical lithium ion capacitors can be effectively improved through implementing both high capacity cathode and high voltage electrolyte. Graphene is considered as one of the most promising cathodes for lithium ion capacitors because of its high electric conductivity, tunable surface functional groups and controllable pore structure. The development of 5-V organic electrolyte provides an opportunity to expand the stable working potential window of graphene cathodes. In this work, we explored the high-voltage electrochemical behavior of graphene cathodes in a 5-V organic electrolyte (3.0-5.0V vs Li/Li+). The prohibiting effect of small pores (< 5 nm) on electrolyte decomposition during cycling is noticed and correlated with the pore size of graphene powders. The results showed the excellent cycling stability (100% retention after 2000 cycles) of graphene cathodes abundant with pores smaller than 5 nm. This finding indicates a new strategy for practical improvement of graphene-related electrode applications. (C) 2016 Curtin University of Technology and John Wiley & Sons, Ltd.