An egg holders-inspired structure design for large-volume-change anodes with long cycle life

Silicon has been considered as a potential alternative of anodes for advanced lithium ion battery as it possesses high capacity and abundance. However, it encounters excessive volume expansion and inferior electoral conductivity, which imposes restrictions on its further development. In order to address these two problems, yolk-shell structure is employed, in which there is a suitable void for the expansion with a shell to protect the core and promote the conductivity. Here, by the inspiration from the egg holders and inverse-opal structure, an egg-stacking-like Si/C composite (ES) anode with spherical air holes was fabricated to gather the yolk-shell particles in a 3D carbon network with abundant channels allowing electrolyte to enter the material, which can facilitate the cycling performance. The half-cell battery assembled with these anodes presents high capacity and good rate performance, with a capacity reduction of only 2-7% per current density. And the cycling performance of ES anode is also praiseworthy that it delivers a high reversible discharge capacity of 2175 mAh g(-1) after 300 cycles at 0.5 A g(-1). This kind of structure design is expected to be applicative for most of large-volume-change anodes. (C) 2019 Elsevier B.V. All rights reserved.