A High‐Performance Supercapacitor Based on KOH Activated 1D C70 Microstructures

Fullerenes are of tremendous interest from fundamental researches to applied perspectives in the past decades. However, their application in supercapacitors has been underdeveloped for a long time. Here, the KOH activation of C₇₀ microtubes is reported at high temperatures, which provides activated samples exhibiting excellent capacitive properties. The improved capacitive performance can be attributed to three aspects: the generation of macropores and micropores, the introduction of oxygen functionalities, and the formation of graphitic carbons from ellipsoidal fullerenes. The optimum activated state for supercapacitor application is achieved at 600 °C, at which the product exhibits the best electrochemical behavior with a gravimetric capacitance of 362.0 F g^?1 at 0.1 A g^?1 and excellent cycling stability with capacitance retention of 92.5% over 5000 cycles at 1 A g^?1.