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Na 0.35 MnO 2 /CNT Nanocomposite from a Hydrothermal Method as Electrode Material for Aqueous Supercapacitors
Author(s) -
Zhang BaiHe,
Yu Feng,
Zhang Lei,
Wang Xiaowei,
Wen Zubiao,
Wu YuPing,
Holze Rudolf
Publication year - 2014
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201400344
Subject(s) - supercapacitor , nanocomposite , materials science , electrolyte , aqueous solution , capacitance , chemical engineering , electrode , electrochemistry , power density , nanotechnology , chemistry , power (physics) , physics , quantum mechanics , engineering
A Na 0.35 MnO 2 /CNT nanocomposite is prepared by a simple and low energy consumption hydrothermal method. Its electrochemical performance as an electrode material for asymmetric supercapacitors with aqueous Na 2 SO 4 solution is investigated. In this nanocomposite less than 2 wt‐% of CNTs are intermingled with the Na 0.35 MnO 2 nanowires. Quite obviously the introduced CNTs efficiently improve the rate performance of the composite. When the current density increases from 0.1 to 10 A · g –1 , the capacitance decreases only slightly from 163 to 125 F · g –1 . When assembled into an asymmetric aqueous supercapacitor using activated carbon as the counter electrode and an aqueous electrolyte solution of 0.5 mol · L –1 Na 2 SO 4 , Na 0.35 MnO 2 /CNT shows an energy density of 33.5 Wh · kg –1 at a power density of 3 kW · kg –1 based on the weights of the two electrode materials, higher than those for simple Na 0.35 MnO 2 , with an energy density of 28.7 Wh · kg –1 at a power density of 3 kW · kg –1 only. The Na 0.35 MnO 2 /CNT nanocomposite presents excellent cycling behavior, no capacitance fading after 10000 cycles, even when dissolved oxygen is not removed from the electrolyte solution. The results are very promising for practical applications of this electrode material since sodium is much cheaper than lithium and its natural resources are rich.