Fe 2 O 3 /nitrogen-doped carbon nanotube composites as positive electrode for high-performance asymmetric supercapacitors

By the simple hydrothermal and high-temperature carbonization, we report the design of a novel Fe 2 O 3 nanoparticles laden nitrogen-doped carbon nanotube composite (Fe 2 O 3 /NC) for high-performance energy storage. The homogeneous dispersion of Fe 2 O 3 nanoparticles on NC provides excellent electron transfer, and its porous structure with mesopore volume facilitates rapid ion transport. The Fe 2 O 3 /NC composite material has high specific capacity (840.9 C g −1 at 1A g −1 ) and good rate performance (85.1% of the capacitance retention from 1 to 10 A g −1 ). Furthermore, a wide working potential window (0–1.5V) was assembled by the asymmetric supercapacitor with Fe 2 O 3 /NC composite as the positive and NC as negative electrode, respectively. The asymmetric supercapacitor exhibits good rate capability (70% of the capacitance retention from 1 to 10 A g −1 ) and high energy density (46.5 Wh kg −1 at 765.8 W kg −1 ). More importantly, the assembled device demonstrates a splendid cycling performance (93.2% capacitance retention after 5000 cycles). The composites with remarkable capacitive performance inspire us to develop superior electrode materials for energy storage.