A facile method was employed to in situ prepare hierarchical mesoporous Fe3O4@C nanofoams through pyrolysis of a post-treated MIL-53(Fe) precursor. Well-defined carbon network-encapsulated ultrasmall and uniform Fe3O4 octahedrons can be obtained by controlling the pyrolysis temperature. This unique artificial shows the excellent lithium storage performance. A reversible discharge capacity of 861.9 mAh·g−1 is observed at 0.1 A·g−1 after 300 cycles. Even at a high current density of 1 A·g−1, the reversible discharge capacity can still reach 605.2 mAh·g−1 after 500 cycles. Good rate capability is also observed, as the specific discharge capacities are 833.6, 729.9, 666.8, 643.6 and 635.6 mAh·g−1 at current density of 0.2, 0.5, 0.8, 1.0 and 1.2 A·g−1, respectively. The attractive electrochemical performance of Fe3O4@C nanofoams should be attributed to the hierarchical foam-like structure, which can effectively relieve the volume change during the lithiation/delithiation process and facilitate fast lithium-ion and electron transport.

中文翻译：

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用于高性能锂存储的金属有机骨架衍生的分层 Fe3O4@C 纳米泡沫

采用一种简便的方法，通过热解后处理的 MIL-53(Fe) 前驱体，原位制备分级介孔 Fe3O4@C 纳米泡沫。通过控制热解温度，可以获得明确的碳网络包裹的超小且均匀的 Fe3O4 八面体。这种独特的人工显示出优异的锂储存性能。在 300 次循环后，在 0.1 A·g-1 下观察到 861.9 mAh·g-1 的可逆放电容量。即使在1 A·g-1的高电流密度下，500次循环后可逆放电容量仍可达到605.2 mAh·g-1。还观察到良好的倍率性能，因为在 0.2、0.5、0.8、1.0 和 1.2 A·g-1 的电流密度下，比放电容量分别为 833.6、729.9、666.8、643.6 和 635.6 mAh·g-1。