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High‐Stacking‐Density, Superior‐Roughness LDH Bridged with Vertically Aligned Graphene for High‐Performance Asymmetric Supercapacitors
Author(s) -
Guo Wei,
Yu Chang,
Li Shaofeng,
Yang Juan,
Liu Zhibin,
Zhao Changtai,
Huang Huawei,
Zhang Mengdi,
Han Xiaotong,
Niu Yingying,
Qiu Jieshan
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201701288
Subject(s) - supercapacitor , materials science , stacking , capacitance , graphene , electrode , current density , nickel , nanotechnology , wetting , chemical engineering , electrolyte , composite material , chemistry , organic chemistry , metallurgy , physics , quantum mechanics , engineering
The high‐performance electrode materials with tuned surface and interface structure and functionalities are highly demanded for advanced supercapacitors. A novel strategy is presented to conFigure high‐stacking‐density, superior‐roughness nickel manganese layered double hydroxide (LDH) bridged by vertically aligned graphene (VG) with nickel foam (NF) as the conductive collector, yielding the LDH‐NF@VG hybrids for asymmetric supercapacitors. The VG nanosheets provide numerous electron transfer channels for quick redox reactions, and well‐developed open structure for fast mass transport. Moreover, the high‐stacking‐density LDH grown and assembled on VG nanosheets result in a superior hydrophilicity derived from the tuned nano/microstructures, especially microroughness. Such a high stacking density with abundant active sites and superior wettability can be easily accessed by aqueous electrolytes. Benefitting from the above features, the LDH‐NF@VG can deliver a high capacitance of 2920 F g −1 at a current density of 2 A g −1 , and the asymmetric supercapacitor with the LDH‐NF@VG as positive electrode and activated carbon as negative electrode can deliver a high energy density of 56.8 Wh kg −1 at a power density of 260 W kg −1 , with a high specific capacitance retention rate of 87% even after 10 000 cycles.