A pinecone-inspired nanostructure design for long-cycle and high performance Si anodes

Abstract

Inspired by pinecone, here we develop a novel kind of direct chemical vapour deposition (CVD) derived graphene-encapsulated porous Si nanoparticles (NPs) on graphene foam (GF). The CVD derived graphene sheets on the surface of Si NPs are partly overlapped, act as the squamae of a pinecone, preventing the direct exposure to the electrolyte. When the Si NPs expand, a sliding between the graphene layers occurs, providing an effective way to accommodate the volume expansion and stabilize the solid electrolyte interphase. As a result, the pinecone-like graphene-encapsulated Si electrodes exhibit a high capacity of 1600 mA h g⁻¹ at a current density of 2100 mA g⁻¹ after 300 cycles and a capacity higher than 800 mA h g⁻¹ at a current density of 8400 mA g⁻¹.