Zn_4Sb_3 Nanotubes as Lithium Ion Battery Anodes with High Capacity and Cycling Stability

摘要

Rational design and synthesis of nanostructured materials have been attracting significant research interest in developing new rechargeable lithium ion batteries (LIBs) with higher energy capacity and longer cycle life.An ideal electrode candidate should allow for high lithium storage capability, fast Li~+ diffusion rate, good structure flexibility, simple production procedure and reliable safety.It has been proposed that electrodes with nanoscale, hollow structures, and efficient transport pathways for ions and electrons can serve as promising candidates for enhanced battery capacity and life.Among many Li-storage compounds, Sb-based intermetallic compounds, such as Co-Sb, Mn-Sb, and Zn-Sb,are attractive anode materials, due to their high theoretical capacities and suitable operating voltages. For instance, orthorhombic ZnSb with a puckered layer structure provides stacked hexagonal channels for lithium insertion,and hexagonal Zn_4Sb_3 has relatively low density and more space for lithium insertion compared to pure Zn and Sb.These zinc antimonide compounds are typically synthesized via heat treatment or high-energy mechanical milling techniques,which can rapidly transform the micron-sized Zn and Sb powder into sub-10 nm particles. However, the charge transport across nanoparticles towards current collectors is mainly by hopping, limiting the electrode capacity. In addition, the volume change of those Sb-based intermetallic compounds during the Li~+ insertion/extraction often results in severe electrode pulverization and thus dramatic capacity loss.