Highly reversible conversion reaction in Sn2Fe@SiOx nanocomposite: A high initial Coulombic efficiency and long lifetime anode for lithium storage

To achieve high reversibility of conversion reactions in SiOx-based anodes, a new class of Sn2Fe@SiOx hybrids is designed to build up insulated/metallic interfaces, in which the Sn2Fe forms electrically conductive network coated on the SiOx to enhance the kinetics and structure stability, demonstrating high initial Coulombic efficiency with average of ~ 78%, large stable capacities of 700 mAh g−1 at 200 mA g−1, and long lifetime more than 1000 cycles at high rate of 1 A g−1 with Coulombic efficiencies beyond 99%.252