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Self‐Assembled Nickel Pyrophosphate‐Decorated Amorphous Bimetal Hydroxides 2D‐on‐2D Nanostructure for High‐Energy Solid‐State Asymmetric Supercapacitor
Author(s) -
Chodankar Nilesh R.,
Dubal Deepak P.,
Ji SuHyeon,
Kim DoHeyoung
Publication year - 2019
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.201901145
Subject(s) - materials science , supercapacitor , electrode , amorphous solid , bimetal , electrochemistry , capacitance , nickel , chemical engineering , nanostructure , bimetallic strip , layered double hydroxides , nanosheet , nanotechnology , hydroxide , composite material , metallurgy , chemistry , crystallography , metal , engineering
To obtain a supercapacitor with a remarkable specific capacitance and rate performance, a cogent design and synthesis of the electrode material containing abundant active sites is necessary. In present work, a scalable strategy is developed for preparing 2D‐on‐2D nanostructures for high‐energy solid‐state asymmetric supercapacitors (ASCs). The self‐assembled vertically aligned microsheet‐structured 2D nickel pyrophosphate (Ni 2 P 2 O 7 ) is decorated with amorphous bimetallic nickel cobalt hydroxide (NiCo‐OH) to form a 2D‐on‐2D nanostructure arrays electrode. The resulting Ni 2 P 2 O 7 /NiCo‐OH 2D‐on‐2D array electrode exhibits peak specific capacity of 281 mA hg −1 (4.3 F cm −2 ), excellent rate capacity, and cycling stability over 10 000 charge–discharge cycles in the positive potential range. The excellent electrochemical features can be attributed to the high electrical conductivity and 2D layered structure of Ni 2 P 2 O 7 along with the Faradic capacitance of the amorphous NiCo‐OH nanosheets. The constructed Ni 2 P 2 O 7 /NiCo‐OH//activated carbon based solid‐state ASC cell operates in a high voltage window of 1.8 V with an energy density of 78 Wh kg −1 (1.065 mWh cm −3 ) and extraordinary cyclic stability over 10 000 charge–discharge cycles with excellent energy efficiency (75%–80%) over all current densities. The excellent electrochemical performance of the prepared electrode and solid‐state ASC device offers a favorable and scalable pathway for developing advanced electrodes.