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Hollow Hierarchical Carbon Spheres Decorated with Ultrathin Molybdenum Disulfide Nanosheets as High‐Capacity Electrode Materials for Asymmetric Supercapacitors
Author(s) -
Lin TsungWu,
Hsiao MinChien,
Wang AiYin,
Lin JengYu
Publication year - 2017
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201600764
Subject(s) - supercapacitor , materials science , molybdenum disulfide , electrode , graphene , electrolyte , nanocomposite , capacitance , power density , chemical engineering , composite number , electrochemistry , carbon fibers , oxide , nanotechnology , cathode , composite material , chemistry , metallurgy , power (physics) , physics , quantum mechanics , engineering
A hierarchically structured nanocomposite consisting of ultrathin MoS 2 nanosheets densely dispersed on the surface of hollow carbon spheres (MoS 2 @HCS) is prepared through a glucose‐assisted, one‐pot synthesis. When evaluated as the cathode material for supercapacitors, MoS 2 @HCS exhibits pseudocapacitive behavior in a KOH electrolyte. More importantly, the capacitive performance of MoS 2 @HCS can be further boosted by activating the composite electrode in a KOH solution. The activation process partially removes the carbonaceous materials covering the MoS 2 surface, which leads to more exposure of active electrode materials to the electrolyte. Activated MoS 2 @HCS exhibits a high specific capacitance value of 458 F g −1 at 1 A g −1 , which is approximately 2.5 times higher than that of the MoS 2 electrode. Furthermore, MoS 2 @HCS exhibits remarkable cycling stability, with a capacitance retention of about 86% over 1000 cycles at 8 A g −1 . To further demonstrate the practical applications of composite electrode, an asymmetric supercapacitor device (ASC) is fabricated by using activated MoS 2 @HCS and reduced graphene oxide as the positive and the negative electrodes, respectively. The fabricated device delivers a maximum energy density of 13.7 Wh kg −1 at a power density of 616 W kg −1 . Even at a high power density of 4.9 kW kg −1 , the ASC device can still retain 80% of the maximum energy density.