Abstract
? 2022 Elsevier B.V.This work reports the synthesis and electrochemical properties of activated carbon nanofibers (ACNF) composited with Li2FeSiO4 for supercapacitors. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller analyzer (BET), transmission electron microscopy (TEM), and thermal gravimetric analyzer (TGA). The electrochemical properties were tested using a variety of techniques, such as cyclic voltammetry (CV), galvanostatic charge-discharge (GDC), and electrochemical impedance spectroscopy (EIS). The structural transformation during charging and discharging processes was studied by in-situ time resolved X-ray absorption spectroscopy (in-situ TRXAS). The ACNF/Li2FeSiO4 presented monoclinic structure with space group of P21/n, although there was a small impurity of FeO. The structural transformations of iron upon cycling in the + 2 to + 3 state were responsible for high capacity of ACNF/Li2FeSiO4 materials. The maximum specific capacitance of 158 Fg?1 at 2 mVs?1 and 201 Fg?1 at 0.25 Ag?1 with the corresponding specific energy of 17.8 Whkg?1 and specific power of 99.7 Wkg?1 were observed. Moreover, this composite material exhibited an excellent cycle performance through maintaining over 85% of its initial capacitance after 1000 cycles. The interesting electrochemical properties of ACNF/Li2FeSiO4 composite nanostructure make it a potential candidate for supercapacitors.
NSTL
Elsevier