Nanosheets-in-nanotube Co3O4-carbon array design enables stable Li-ion storage

Carbon composite products with different structures have been developed and used as anode for lithium-ion batteries due to the superior elasticity of carbon, which can keep the morphology integrity of the electrode materials in the process of the multiple cycles. Herein, a novel structure of nanosheets-in-nanotube Co 3 O 4 /carbon arrays is fabricated by the method of modified chemical vapor deposition (CVD). The carbon nanotube (CNT) layer acting as an outside coater can efficiently prevent the electrode from fragmentation and consequently ensure its shape integrity. The specific structure shows the ultra-stable cycle life (850 mAh g −1 after 200 cycles at 0.5C) and high rate capability (694 mAh g −1 at 2C). The favorable electrochemical properties are contributed to the combination of the wrapped elastic carbon and the enclosed Co 3 O 4 nanosheets in the lithiation process, which is confirmed by an in situ transmission electron microscope.