Tin-based
materials with high specific capacity have been studied
as high-performance anodes for energy storage devices. Herein, a SnO
x
(x = 0, 1, 2) quantum dots@carbon
hybrid is designed and prepared by a binary oxide-induced surface-targeted
coating of ZIF-8 followed by pyrolysis approach, in which SnO
x
quantum dots (under 5 nm) are dispersed
uniformly throughout the nitrogen-containing carbon nanocage. Each
nanocage is cross-linked to form a highly conductive framework. The
resulting SnO
x
@C hybrid exhibits a large
BET surface area of 598 m2 g–1, high
electrical conductivity, and excellent ion diffusion rate. When applied
to LIBs, the SnO
x
@C reveals an ultrahigh
reversible capacity of 1824 mAh g–1 at a current
density of 0.2 A g–1, and superior capacities of
1408 and 850 mAh g–1 even at high rates of 2 and
5 A g–1, respectively. The full cell assembled using
LiFePO4 as cathode exhibits the high energy density and
power density of 335 Wh kg–1 and 575 W kg–1 at 1 C based on the total active mass of cathode and anode. Combined
with in situ XRD analysis, the superior electrochemical
performance can be attributed to the SnO
x
-ZnO-C asynchronous and united lithium storage mechanism, which is
formed by the well-designed multifeatured construction composed of
SnO
x
quantum dots, interconnected carbon
network, and uniformly dispersed ZnO nanoparticles. Importantly, this
designed synthesis can be extended for the fabrication of other electrode
materials by simply changing the binary oxide precursor to obtain
the desired active component or modulating the type of MOFs coating
to achieve high-performance LIBs.