Developing new earth-abundant materials has been attracted more and more attention for energy storage applications. In this talk, I would like to talk about our recent work related to development of Aluminum ion battery (AIB). AIB was demonstrated recently based on Al foil anode, graphite cathode and ionic liquid electrolyte. Much remains to be done to increase the cathode capacity and to understand details of the anion-graphite intercalation mechanism. Here, we developed a freestanding film of natural graphite flakes bound by a binder as AIB cathode. The specific capacity and Coulombic efficiency of the battery was achieved ~110 mAh/g and ~98% respectively, at a current density of 99 mA-g-1 with clear discharge voltage plateaus ~2V. Furthermore, analytical results of coupled ex-situ XAS and density functional theory (DFT) indicated that the molecular structure of intercalants in the graphite layer could be constructed successfully, paving the way for better understanding the mechanism of anion de-/ intercalation in AIB.