Two-dimensional
MXene materials have received a great deal of attention
for their use in energy storage. However, MXene usually suffers from
severe self-restacking, which leads to the active sites being covered,
hinders the electrolyte ion transport, and thus affects the electrochemical
performance. In the present work, molybdenum trioxide with oxygen
vacancy (MoO3–x
) nanobelts as the
interspacer and active electrode material were introduced into Ti3C2T
x
, a member of MXenes
family, by the vacuum-assisted filtration method to form the self-standing
film. Conductive Ti3C2T
x
nanosheets bridge MoO3–x
nanobelts to facilitate electron transfer, and MoO3–x
nanobelts are randomly intercalated between Ti3C2T
x
nanosheets to
effectively prevent self-restacking of Ti3C2T
x
, provide pseudocapacitance, and promote
wettability. The Ti3C2T
x
/MoO3–x
-50% displays high
volumetric/gravimetric capacitance performances (1893.2 F cm–3 and 733.8 F g–1 at 1 A g–1 and
at 20 A g–1 with 1578.7 F cm–3 and 611.9 F g–1), outperforming reported Ti3C2T
x
, Ti3C2T
x
-based, or MoO3-based composites. Furthermore, Ti3C2T
x
/MoO3–x
-50% presents capacitance retention of 90.2% after 2000 cycles, showing
good cycling stability. The assembled Ti3C2T
x
/MoO3–x
-50%//Ti3C2T
x
/MoO3–x
-50% flexible solid-state supercapacitor
using a PVA/H2SO4 gel electrolyte displays high
volumetric/gravimetric energy densities (25.8 W h L–1 at 448.7 W L–1 and 10.0 W h kg–1 at 173.9 W kg–1) and good cycling stability. In
addition, the supercapacitor shows little significant capacitance
loss after 100th bending cycle of 180°, demonstrating excellent
flexibility. Such a self-standing Ti3C2T
x
/MoO3–x
composite film and its flexible solid-state symmetric supercapacitor
show great potential in wearable and portable electronic devices.