Porous Carbon Materials Prepared from Potassium Citrate for Zinc–Ion Capacitor: Effect of Preparation Method

Slow carbonization (SC) and fast carbonization (FC) methods were applied and compared during the preparation of carbon materials using potassium citrate as raw material. The porous carbon material obtained by the SC method (SCPC800) had a slightly higher specific surface area than that obtained by the FC method (FCPC800). When SCPC800 was applied in the construction of a zinc–ion capacitor (ZIC), the obtained ZIC displayed a high mass specific capacitance (MSC) value of 309.5 F g −1 and a specific energy of 155.2 Wh kg −1 at the 0.2 A g −1 current density. FCPC800 showed similar electrochemical performance as SCPC800. The ZIC with the FCPC800 as electrode exhibited an MSC value of 300.7 F g −1 with a specific energy of 150.8 Wh kg −1 at the 0.2 A g −1 current density. Meanwhile, the SCPC800 and FCPC800-based ZICs showed good rate capability and cycle stability. Compared with the SC method, the FC method showed a significant advantage in reducing sample preparation time, which can greatly increase the preparation efficiency and reduce energy consumption. Therefore, as an efficient method, the FC method showed broad application prospects in the preparation of carbon materials for ZIC. Graphical Porous carbon materials prepared from potassium citrate for zinc-ion capacitor