Metal-organic frameworks derived germanium oxide nanosheets for large reversible Li-ion storage

•The GeO2 nanosheet is investigated as the Li-battery electrode for the first time.•Ge-organic framework is used as the precursor.•The GeO2 nanosheet shows large Li-storage capacity and very long cycle life.

A Ge-based metal-organic framework (MOF) precursor [C6H10(NH2)2Ge3O6] is used to fabricate two-dimensional GeO2 nanosheets in this work. The obtained micrometer-sized GeO2 nanosheet delivers superior lithium-storage capability during long cycling (an initial reversible capacity of 1315 mAh g− 1 at 100 mA g− 1 and the retained capacity of 1393 mAh g− 1 after 350 cycles). The observed large capacity and good cyclability have been mainly attributed to its nanosheet structure inherited from the MOF precursor, which can facilitate the electrolyte infusion and the lithium diffusion, maintain the structural stability, and alleviate the large volume change of the electrode during repetitive lithiation/delithiation process.

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