Lithium ion batteries (LIBs) have dominated the power market of portable electronics due to the long cycle life, high energy efficiency and low self-discharge properties. However, the energy and power densities of current commercial LiCoO2/Graphite-based LIBs are insufficient for applications in the large-scale energy storage technologies. Here, we report a nanostructured porous Fe2N conversion anode completely encapsulated in carbon microboxes that are prepared by a facile conversion reaction from polydopamin coated Fe2O3 microcubes. The resulting carbon microboxes not only protect the Fe2N from oxidation in the air, but also reduce the electrode−electrolyte contact area, yielding high Coulombic efficiency. In addition, the internal void spaces are ideal for accommodating the volume expansion of Fe2N during charge/discharge processes, and the carbon shells act as a barrier limiting most solid-electrolyte interphase formation on the surface of the carbon films instead of forming on individual particles. The optimal composite Fe2N@C structures exhibited excellent electrochemical performance, at a high rate of 10 A g-1 with a capacity retention of over 85% for 2500 cycles. This work provides new direction on designing and constructing protective layer for air unstable conversion materials for potential applications as lithium ion battery electrode materials with high capacity, rate capabilities and good cyclability.

Air-stable porous Fe2N encapsulated in carbon microboxes with high-rate and long-life lithium storage performance

254th National Meeting (2017)

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