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Alternative‐Ultrathin Assembling of Exfoliated Manganese Dioxide and Nitrogen‐Doped Carbon Layers for High‐Mass‐Loading Supercapacitors with Outstanding Capacitance and Impressive Rate Capability
Author(s) -
Jeong JaeMin,
Park Seung Hwa,
Park Hong Jun,
Jin Se Bin,
Son Seon Gyu,
Moon JongMin,
Suh Hoyoung,
Choi Bong Gill
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202009632
Subject(s) - supercapacitor , materials science , capacitance , electrolyte , gravimetric analysis , chemical engineering , carbon fibers , electrode , manganese , electrochemistry , carbonization , nanotechnology , composite material , scanning electron microscope , composite number , metallurgy , organic chemistry , chemistry , engineering
Manganese dioxide (MnO 2 ) materials have received much attention as promising pseudocapacitive materials owing to their high theoretical capacitance and natural abundance. Unfortunately, the charge storage performance of MnO 2 is usually limited to commercially available mass loading electrodes because of the significantly lower electron and ion migration kinetics in thick electrodes. Here, an alternatively assembled 2D layered material consisting of exfoliated MnO 2 nanosheets and nitrogen‐doped carbon layers for ultrahigh‐mass‐loading supercapacitors without sacrificing energy storage performance is reported. Layered birnessite‐type MnO 2 is efficiently exfoliated and intercalated by a carbon precursor of dopamine using a fluid dynamic‐induced process, resulting in MnO 2 /nitrogen‐doped carbon (MnO 2 /C) materials after self‐polymerization and carbonization. The alternatively stacked and interlayer‐expanded structure of MnO 2 /C enables fast and efficient electron and ion transfer in a thick electrode. The resulting MnO 2 /C electrode shows outstanding electrochemical performance at an ultrahigh mass loading of 19.7 mg cm −2 , high gravimetric and areal capacitances of 480.3 F g −1 and 9.4 F cm −2 at 0.5 mA cm −2 , and rapid charge/discharge capability of 70% capacitance retention at 40 mA cm −2 . Furthermore, asymmetric supercapacitor based on high‐mass‐loading MnO 2 /C can deliver an extremely high energy of 64.2 Wh kg −1 at a power density of 18.8 W kg −1 in an aqueous electrolyte.