Transition metal oxides have vastly limited practical application as electrode materials for lithium-ion batteries (LIBs) due to their rapid capacity decay. Here, a versatile strategy to mitigate the volume expansion and low conductivity of Fe3 O4 by coating a thin carbon layer on the surface of Fe3 O4 nanosheets (NSs) was employed. Owing to the 2D core-shell structure, the Fe3 O4 @C NSs exhibit significantly improved rate performance and cycle capability compared with bare Fe3 O4 NSs. After 200 cycles, the discharge capacity at 0.5 A g-1 was 963 mA h g-1 (93 % retained). Moreover, the reaction mechanism of lithium storage was studied in detail by ex situ XRD and HRTEM. When coupled with a commercial LiFePO4 cathode, the resulting full cell retains a capacity of 133 mA h g-1 after 100 cycles at 0.1 A g-1 , which demonstrates its superior energy storage performance. This work provides guidance for constructing 2D metal oxide/carbon composites with high performance and low cost for the field of energy storage.
Keywords: core-shell structures; electrochemistry; hydrothermal synthesis; lithium-ion batteries; nanostructures.
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