Novel one-dimensional hollow carbon nanotubes/selenium composite for high performance Al-Se batteries.

Abstract

Herein, we successfully prepared one-dimensional nanowire with carbon-coated selenium (Se@CW) by using a simple wet chemical method, and obtained a one-dimensional hollow Se@C nanotube (Se@CT) after the subsequent calcination treatment. We have formed a new Al-Se secondary battery by using Se@CT as cathode and metal aluminum as anode in AlCl3/[EMIm]Cl electrolyte. It is believed that the oxidation intermediate of Se in Al-Se batteries may not only have 〖 Se 〗_ 2 ^ 2+ , but there may be other oxidation intermediates, such as Se4+, Se2+ and 〖 Se 〗_ 8 ^ 2+ etc. Therefore, Se@CT exhibits excellent electrochemical performance in Al-Se batteries. Its initial discharge specific capacity is as high as 447.2 mAh g-1 at a current density of 200 mA g-1, and the operating voltage is above 1.6 V. Its energy density approaches 708.8 Wh kg-1, and the capacity is still 162.9 mAh g-1 after 200 cycles at a current density of 500 mA g-1, and the corresponding capacity retention rate is up to 83.5 %. In addition, its electrochemical performance is far superior to that of Se@CMK-3 in Al-Se batteries and the electrochemical properties of carbon materials, oxides and sulfide electrode materials in some aluminum ion batteries, which will open up a new direction for the development of new secondary aluminum-based batteries.