3D Porous Compact 1D/2D Fe2 O3 /MXene Composite Aerogel Film Electrodes for All-Solid-State Supercapacitors.

Abstract

2D MXene nanoflakes usually undergo serious restacking, that easily aggravates during the traditional vacuum-assisted filtration process; and thus, hinders the electrochemical performance of the corresponding film electrodes. Herein, 3D porous compact 1D/2D Fe2 O3 /MXene aerogel film electrode with an enhanced electrochemical performance is fabricated by freeze-drying assisted mechanical pressing. An introduction of 1D α-Fe2 O3 nanorods can not only alleviate the restacking of 2D MXene but also provide additional pseudocapacitance for the composite film system. Thus, the resulting Fe2 O3 /MXene aerogel film electrode shows an enhanced specific capacitance of 182 F g-1 (691 mF cm-2 ) at a current density of 1 A g-1 in 3 m H2 SO4 electrolyte as well as with 81.74% capacitance retention after 10000 charge-discharge cycles. Besides, the addition of 1D α-Fe2 O3 nanorods has a significant contribution in the volumetric capacitance of the composite aerogel film (150 F cm-3 ), which is 2.68 times that of the pure MXene aerogel film (56 F cm-3 ). Moreover, the fabricated all-solid-state symmetric supercapacitor (SSSC) delivers a superior areal energy density of 3.61 µWh cm-2 at a power density of 119.04 µW cm-2 . This rapid-forming 3D porous, binder-free, and freestanding aerogel film provides a progressive strategy for the fabrication of MXene-based electrode for supercapacitors.