Although the initial discharge and
charge capacities of carbon-supported SnO2 nanowires (1627 and
672mA h g1, respectively) are lower than that of non-supported
SnO2 nanowires due to the existence of carbon, it shows a lower
initial irreversible capacity loss of 58.7%. The second and sixtieth
discharge capacities of carbon-supported SnO2 nanowire arrays
are 722 and 554mA h g1, with the corresponding charge
capacities of 671 and 521mA h g1, respectively, giving rise to a
much higher Coulombic efficiency of 92.9% and 94.0%. Moreover,
the discharge capacity of carbon-supported SnO2 nanowires after
60 cycles is much higher than that of non-supported SnO2
nanowires, indicating an improved cycling performance, which is
evidenced by the comparative cycling performance curves shown
in Fig. 5c. The enhanced performance of carbon-supported SnO2
nanowire arrays is mainly ascribed to the presence of the carbon
support, which can serve as a buffering layer to better cushion the
stress, reduce the volume variation, and protect the SnO2
nanowires from severe structural degradation during the insertion-
deinsertion process of lithium ions. Additionally, the discharge
capacity of carbon-supported SnO2 nanowire arrays is also
slightly higher than that of similar materials synthesized within
the SBA-15 nanorods template [34]. The possible reason is that the
mesoporous carbon template used in this work has long
mesoporous channels and the derived SnO2 nanowires possess
high aspect ratio accordingly, which provide a direct expressway
for efficient Li+ transport. Moreover, the carbon supporting layer in
this work was obtained by calcination of phenolic resin under a
relatively high temperature of 800 C, which is helpful to enhance
the conductivity of the electrode