A Hybrid Electrode of Co(3)O(4)@PPy Core/Shell Nanosheet Arrays for High-Performance Supercapacitors

Herein, combining solverthermal route and electrodeposition, we grew unique hybrid nanosheet arrays consisting of Co(3)O(4) nanosheet as a core, PPy as a shell. Benefiting from the PPy as conducting polymer improving an electron transport rate as well as synergistic effects from such a core/shell structure, a hybrid electrode made of the Co(3)O(4)@PPy core/shell nanosheet arrays exhibits a large areal capacitance of 2.11 F cm(−2) at the current density of 2 mA cm(−2), a ~4-fold enhancement compared with the pristine Co(3)O(4) electrode; furthermore, this hybrid electrode also displays good rate capability (~65 % retention of the initial capacitance from 2 to 20 mA cm(−2)) and superior cycling performance (~85.5 % capacitance retention after 5000 cycles). In addition, the equivalent series resistance value of the Co(3)O(4)@PPy hybrid electrode (0.238 Ω) is significantly lower than that of the pristine Co(3)O(4) electrode (0.319 Ω). These results imply that the Co(3)O(4)@PPy hybrid composites have a potential for fabricating next-generation energy storage and conversion devices. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s40820-015-0069-x) contains supplementary material, which is available to authorized users.