Rate capability improvement of polypyrrole via integration with functionalized commercial carbon cloth for pseudocapacitor

Rate capability of polypyrrole (PPy) was improved through additional doping by oxygen containing functional groups introduced in the substrate of functionalized carbon cloth (FCC). The PPy deposited on surfaces of carbon fibers in FCC displayed good rate capability, 70% of its capacitance (341.2 mF cm(-2) at 1 mA cm(-2)) can be retained when the charge/discharge current density increased 20 times to 20 mA cm(-2), while the PPy deposited on untreated carbon cloth (CC) could only retain 52% of its capacitance (308.7 mF cm(-2) at 1 mA cm(-2)). PPy/FCC also displayed excellent cycling stability, 96% of its initial capacitance can be retained after 10,000 charge/discharge cycles. The asymmetric supercapacitor (ASC) assembled by using PPy/FCC as anode and crumpled MnO2 nanosheets electrochemically deposited on carbon cloth (MnO2/CC) as cathode also displayed good rate capability. When the charge/discharge current density increased 10 times from 1 to 10 mA cm(-2), the ASC can retain 79% of its volumetric capacitance (from 1.78 to 1.41 F cm(-3)). The ASC demonstrated a high volumetric energy density of 0.80 mWh cm(-3) at 12.85 mW cm(-3). After 10,000 galvanostatic charge/discharge cycles, the ASC can retain 90.7% of its capacitance, demonstrating its good cycling stability. (C) 2016 Elsevier B.V. All rights reserved.