Compact Sn/C composite realizes long-life sodium-ion batteries

Sodium-ion batteries are considered as a promising low-cost alternative to commercial lithium-ion batteries. However, the harsh preparation conditions and unsatisfactory electrochemical performance of most sodium-ion batteries anode materials limit their commercial applications. Herein, we develop a new alloying/dealloying method for producing nano-scale tin from freezing point to room temperature. Due to the unique surface properties of tin particles, a tin/carbon composite with a compact structure is obtained. When coupled with a diglyme-based electrolyte, tin/carbon composite (contains 60 wt.% tin) exhibits a reversible capacity of 334.8 mAh·g−1 after 1,000 cycles at 500 mA·g−1. An as-prepared tin/carbon anode∥high-load vanadium phosphate sodium full cell (N/P ratio: 1.07) shows a stable cycle life of 300 cycles at 1 A·g−1. The achievement of such an excellent performance can be ascribed to the carbon conductive network and robust solid electrolyte interphase film, which facilitates the fast transportation of electrons and Na ions. This work provides a new idea to prepare other alloyed anode materials for high-performance sodium-ion batteries.