High Voltage Carbon‐Based Cathodes for Non‐Aqueous Aluminium‐Ion Batteries**

Abstract Four different forms of carbon: activated carbon (AC) from human hair, AC from hemp fibers, a carbon fullerene extract consisting of C 60 and C 70 fullerene (CFEx) and Super‐P carbon black were tested and compared as cathodes for non‐aqueous aluminium‐ion batteries (AIBs). These materials differ in their general structure, porosity and morphology. Fullerenes display a crystalline structure, whereas hemp fibers, Super‐P and hair are amorphous in nature. Of all materials, AC obtained from hair recorded the highest specific capacity after 50 cycles at 103 mAh g −1 with a Coulombic efficiency of ∼90 % at a current rate of 50 mA g −1 . Both hemp fibers and Super‐P achieved their highest specific capacities at 56 mAh g −1 and 84 mAh g −1 respectively. CFEx recorded its highest capacity at 78 mAh g −1 and maintained it for 50 cycles. The cells were charged and discharged to 2.45 V and 0.2 V respectively.