Construction of three‐dimensional crumpled Ni‐Co TMOs for electrochemical energy storage

Abstract

AbstractDue 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.