AbstractA high‐performance Al/graphite battery has been investigated, employing a natural graphite cathode (NG) and 1‐ethyl‐3‐methylimidazolium chloride (EMIMCl):AlCl3 as electrolyte. The employed graphite is characterized by excellent reversibility as revealed by electrochemical tests and ex‐situ XRD. The Al/EMIMCl:AlCl3/NG battery showed extraordinary performance in terms of rate capability, and cycle life. The cell delivered a capacity of 110 mAh g−1 at lower current values, retaining 90 % and 60 % of the capacity employing a current of 20 A g−1 and 50 A g−1, respectively (i. e., a complete charge‐discharge cycle in 35 and 9 seconds, respectively). Furthermore, the cycling test performed using a current of 20 A g−1 revealed an extremely long calendar life of half million of cycles. The practical applicability of the investigated Al/graphite system has been ascertained; this involved estimating the energy efficiency as a function of current rate and carefully calculating the practical energy densities that can be obtained from the system.