Ultrafast ionic diffusion of debossed carbon nanocomposites for lithium storage

Highlights: • Debossed carbon nanocomposites for lithium storage. • Well-dispersed metal nanoparticles in the carbon matrix. • Enhanced ionic diffusion ability and competent accommodation of volume change. • Improved electrochemical performance of ultrafast lithium storage. Owing to their superb mechanical durability resulting from the dramatic volume changes of the Sn nanoparticles and high electrical conductivity, carbon and tin (Sn) nanocomposites have received an increasing attention in view of their application as anode materials for lithium ion batteries (LIBs). However, due to the poor ionic diffusion capability for Li ions during the cycling, the low ultrafast performance for energy storage remains rather limited. In the present study, aiming to improve the ionic diffusion capability for Li ions, we suggest a novel design of the debossed structure of carbon and Sn nanocomposites by electrospinning, carbonization, and the debossing process. The electrode based on the debossed structure exhibits a noticeable cycling stability and high discharge capacity (677 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹), an excellent rate capability (482 mA h g⁻¹ at 2000 mA g⁻¹), and an outstanding ultrafast cycling stability (275 mA h g⁻¹ after 500 cycles at 2000 mA g⁻¹). Therefore, this novel design of the debossed structure based on carbon and Sn nanocomposites offers attractive effects, such as the effective accommodation of dramatic volume changes for the Sn nanoparticles, as well as an improved ionic diffusion performance of Li ions.