[n]Phenacenes: Promising Organic Anodes for Potassium-Ion Batteries

As an alternative to Li-ion batteries, K-ion batteries have attracted attention because of the abundant potassium reserves, low prices, and environmental friendliness of K resources. In the present work, using the first-principles calculations, we predict [n]phenacenes as promising intercalation-type anode materials for K-ion batteries that are superior to graphite. [n]Phenacenes have a small volume expansion ratio of <50% and a high theoretical specific capacity of >700 mAh/g during the K intercalation. The electron transfer upon the K intercalation results in a good electrical conductivity and a low average open-circuit voltage. Finally, the low diffusion barrier of K ions in [n]phenacenes implies a rapid charge/discharge rate performance. All these results suggest that aromatic [n]phenacenes are promising anode materials for K-ion batteries.