Due to excellent electrochemical performances, mixed transition metal oxides (TMOs) as electrode materials have attracted scholarly attention. However, the issues of volume expansion, unstable structure, and low electrical conductivity have limited their development for lithium battery (LIB). Drawing on the strategy of MOFs derivation synthesis combined with low temperature hydrothermal method, this study successfully synthesized the three‐dimensional (3D) NiCo2O4@Fe2O3 with a flower‐like crossing channel and a surface crumpled structure. As anode for LIBs, NiCo2O4@Fe2O3 exhibits more reliable performance than Ni−Co oxides. Our experiments verified that the Ni−Co composite electrical conductivity and cycling stability were both improved by the Fe2O3 coating. Under the high current density of 1000 mA g−1, the capacity decay rate of NiCo2O4@Fe2O3 tends to be stable after 60 cycles, and the capacity remains at 945 mAh g−1 after 400 cycles. Besides, the specific crossing porous‐channel structure mode improved the composite's carrier transport efficiency, and coulombic efficiency reached 100 % after 400 cycles. Noteworthy is the fact that the crumpled surface structure formed by the 2D Ni−Co nanosheets promotes the construction of heterostructures, further enhances the interface capacitance effect, and strengthens the rating capacity.
Metal–Organic frameworks (MOFs) and their derivatives
have
been widely used in lithium-ion batteries (LIBs) since their introduction
because of their high porosity, large specific surface area, and structural
and functional versatility. In this paper, the Zn–Co MOF-derived
nanocages oxides with porous channel-crossing structure were successfully
prepared by a low-temperature calcination self-assembly strategy.
As anode of LIBs, the reduced graphene oxide (RGO)/ZnO/Co3O4 has excellent rating and cycling performances compared
to the RGO/Co3O4. The RGO/ZnO/Co3O4 electrode maintains a reversible capacity of about
900 mAh g–1 after 500 cycles, which is 1.5 times
higher than that of the RGO/Co3O4 electrode.
At high current density of 2 A g–1, the discharge
specific capacity of RGO/ZnO/Co3O4 is 500 mAh
g–1, which is 1.25 times that of RGO/Co3O4. The superior electrochemical performance is attributed
to its specific three-dimensional porous channel structure and internal
Zn/Co oxide semiconductor heterointerface structure, which increases
the effective active area of the electrode, improves the storage capacity
and carrier transport efficiency of Li+, and enhances the
overall structural stability as well as electrochemical activity.
In addition, the improved electrochemical performance cannot be achieved
without the synergistic effect of ZnO and Co3O4.
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