Fabrication of MnO2@Porous Carbons with High Energy and Power Density and Their Application in Supercapacitors

• Published in: Advanced energy and sustainability research 2024-08, Vol.5 (8), p.n/a
• Main Authors: Cao, Yuan‐Jia, Lu, Cui‐Ying, Wang, Zhen, Bai, Rui, Liu, Guanghui
• Format: Article
• Language: English
• Subjects: electrochemical performance; impregnation method; MnO2/PC composite; supercapacitors
• ISSN: 2699-9412; 2699-9412
• DOI: 10.1002/aesr.202300164

MnO2@PCs (porous carbons) exhibiting high energy and power density are utilized as supercapacitor electrodes and prepared by impregnating porous carbons (PCs) derived from coal tar pitch (CTP) with KMnO4 as the manganese source. This study systematically investigates the impact of MnO2 loading on the microstructure and electrochemical performance in sample. It is found that the specific surface areas (SSA) of all MnO2@PCs significantly reduced compared to that of the PCs 2789 m2 g−1. The suggested mechanism might be a combination of the energy storage mechanism of dual layer capacitors with pseudo‐capacitance due to redox reactions of MnO2. Notably, MnO2@PCs‐0.0075 exhibits a maximum SSA of 1454.62 m2 g−1. Its specific capacitance reached 561 F g−1 at 0.5 A g−1, while the capacitance of the PCs increased by 81.5% to 309 F g−1. Remarkably, the Coulombic efficiency remained at 100%. The power density and energy density are determined in a two‐electrode test system to be 0.5 kW kg−1 and 58.01 Wh kg−1, respectively, at 0.5 A g−1. Concluding from these results and related literature, the MnO2 content significantly influences the electrochemical performance, suggesting that MnO2@PCs‐0.0075 could be a promising supercapacitor (SC) electrode material, provided its capacitance retention is enhanced. Preparation of porous carbon (PC) with high specific surface area (SSA) by KOH activation method using coal tar pitch (CTP) from Yulin, China as carbon precursor. CTP‐PC was impregnated in a reduced potassium permanganate solution to obtain MnO2@PC. Through various characterizations, it was found that PC has excellent electrochemical performance as an electrode material for supercapacitors (SC).