Pinecone-like Silicon@Carbon Microspheres Covered by Al2O3 nano-petals for lithium-ion battery anode under high temperature

Abstract

Silicon anode has aroused ever-increasing attention for lithium ion batteries (LIBs) due to its superior features of high reversible capacity and avoidance of the fatal threat from dendrite, etc. However, silicon anode has been suffering the huge capacity degradation and poor cycle life derived from volume expansion upon lithiation/delithiation. Herein, a multi-dimensional structured engineering strategy has been adopted to generate a pinecone-like carbon microsphere filled with silicon particles, covered by Al2O3 nano-petals (Si@C@Al2O3), via a facile self-assembled method. Such a well-designed aluminum oxide and carbon coating can alleviate the volume expansion of silicon and improve electronic conductivity. The as-obtained pinecone-like Si@C@Al2O3 composites rendered an ultra-large reversible capacity of 1405 mA h g−1 at a current density of 5 A g−1 after 1000 cycles under a high temperature of 80 °C. Such an impressive performance could be ascribed to stable micro-structure and improved kinetics originating from integration effect from the covering of 2D Al2O3 nano-petals with abundant pores and compact carbon coating. Therefore, the silicon-based material is considered as a promising candidate for high-performance anodes for Li-ion batteries, especially under high temperature.