Facile synthesis of porous waist drum-like α-Fe 2 O 3 nanocrystals as electrode materials for supercapacitor application

In this work, we first report the facile synthesis of porous waist drum-like α-Fe 2 O 3 nanocrystals in high yield by hydrothermal method for supercapacitor application. The as-prepared porous waist drum-like α-Fe 2 O 3 nanocrystals have an equatorial diameter of 100–130 nm and length of 150–200 nm, which are self-assembled by numerous nanoparticles. The formation mechanism of the porous waist drum-like α-Fe 2 O 3 nanocrystals was proposed according to a series of time-dependent experiments. The specific surface area and pore size of the porous waist drum-like α-Fe 2 O 3 nanocrystals were measured to be 28.6 m 2 g −1 and 1.7 nm, respectively. Electrochemical measurements indicate that the porous waist drum-like α-Fe 2 O 3 nanocrystals electrode exhibits noticeable pseudocapacitive properties with a high specific capacitance up to 234 F g −1 at 2 A g −1 as well as good cycling stability and high capacitance retention of 84.6% after 2000 charge–discharge cycles. The excellent pseudocapacitive performance could be due to the unique nanostructure of the porous waist drum-like α-Fe 2 O 3 nanocrystals, which can provide fast ion/electron transfer.