Mesoporous carbon nanosheet-assembled flowers towards superior potassium storage

Abstract Potassium-ion batteries (PIBs) are attracted tremendous interest for large-scale energy storage systems (ESSs) owing to their economic merits. However, the main challenges of the PIBs are sluggish K-ion diffusion and large volume variations in the potassium repeated intercalation/deintercalation. Herein, mesoporous carbon nanosheet-assembled flowers (abbreviated as F-C) are designed as an original anode for superior-performance PIBs. Specifically, the F-C anode exhibits a high K-storage capacity (e.g., 381 mA h/g at 50 mA/g during the 2nd cycle), excellent rate performance (e.g., 101 mA h/g at 2.0 A/g) and superior long cycle capability. Such excellent K-ion storage property is largely benefited from the large surface area (∼141 m2/g) and reasonable pore volume (0.465 cm3/g), which not only stimulates rapid K-ions diffusion and relieves the huge volume strain, but also exposes extensive active sites for K-ion capacitive storage.