Polypyrrole-encapsulated Fe2O3 nanotube arrays on a carbon cloth support: Achieving synergistic effect for enhanced supercapacitor performance

It is highly attractive to design Fe2O3-based nanocomposite anodes for supercapacitors (SCs). Herein, polypyrrole-encapsulated Fe2O3 nanotube arrays grown on carbon cloth (Fe2O3 NTs@PPy/CC) were fabricated by combination of sacrificial template and electrodeposition methods. Such Fe2O3 NTs@PPy/CC exhibits boosted pseudocapacitance and stability. In 1 M Na2SO4, it delivers a specific capacitance of 237 mF cm(-2) at 1 mA cm(-2), and still retains 80% of initial capacity at 10 mA cm(-2) even after 10,000 cycles. The theoretical calculation results reveal that PPy exhibits a strong adhesion on the surface of Fe2O3, and then effectively stabilizes the electrode structure. The interface between Fe2O3 and PPy possesses more stable Na+ storage sites to substantially enhance pseudocapacitance. The interactions of Fe2O3 nanotube arrays and conductive polymers can simultaneously cause faster ion transfer, more surface charge storage, and higher structural stability for Fe2O3. The asymmetric aqueous supercapacitor devices consisted of Fe2O3 NTs@PPy and MnO2 electrodes with maximum operating potential of 2.0 V achieve a high areal energy density of 59.4 mu Wh cm(-2) (24.2 Wh kg(-1)) at a power density of 1 mWh cm(-2) (408.2 W kg(-1)) along with good stability. This work seeks a deeper insight for synergistic effect between PPy and Fe2O3, and offers a novel strategy to design the nanostructured composite with enhanced interface area for energy storage. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study successfully designed and prepared Fe2O3-based nanocomposite anodes for supercapacitors, with high specific capacitance and cycling stability. The surface encapsulation of PPy effectively enhanced the pseudocapacitive performance of Fe2O3. Additionally, the interface between Fe2O3 and PPy constructed more stable Na+ storage sites, significantly enhancing the capacitance energy storage capacity. By interacting with conductive polymers, faster ion transfer, more surface charge storage, and higher structural stability were achieved.