Constructing graphitization-graded porous carbon using olive leaves as a carbon source for a high-performance zinc-ion hybrid capacitor

In this work, the Zn/OLPC-2 hard shell cells present a specific capacity of 176.2 mA h g −1 at 0.1 A g −1 . They achieve a cycle life of 15 000 times and a capacity retention of 96.8% at 10 A g −1 .