Enabling high sodium storage performance of micron-sized Sn4P3 anode via diglyme-derived solid electrolyte interphase

Abstract

Sodium-ion batteries (SIBs) have great potential for large scale energy storage applications due to geopolitical abundance of sodium resource. However, the development of SIBs is hindered by the available anodes with high reversible capacity and long cycle life. Herein, we report that micron-sized Sn4P3 anode delivers superior sodium storage performance when used in combination with diglyme-based electrolyte. The first reversible capacity of Sn4P3 anode in diglyme-based electrolyte reaches up to 960.3 mAh/g at current density of 100 mA/g, and a record capacity after 100 cycles (i.e. 719.7 mAh/g) is achieved for Sn4P3-based anodes to date. Moreover, the initial Coulombic efficiency of the anode is 89.8%, which is one of the highest values among Sn4P3-based anodes. Ex-situ SEM and XPS study reveals that the outstanding performance is mainly enabled by the ether-derived solid electrolyte interphase, which preserves the integrity of electrode and constructs a robust interphase with favorable kinetics.