A stable room temperature sodium sulfur battery
High energy rechargeable batteries based on earth abundant materials are important for mobile and stationary storage technologies. Rechargeable sodium sulfur batteries able to operate stably at room temperature are among the most sought after platforms because such cells take advantage of a two electron redox process to achieve high storage capacity from inexpensive electrode materials. Here we report a room temperature sodium sulfur battery that uses a microporous carbon sulfur composite cathode, and a liquid carbonate electrolyte containing the ionic liquid 1 methyl 3 propylimidazolium chlorate tethered to SiO2 nanoparticles. We show that these cells can cycle stably at a rate of 0.5 C (1 C=1675, mAh g 1) with 600 mAh g 1 reversible capacity and nearly 100% Coulombic efficiency. By means of spectroscopic and electrochemical analysis, we find that the particles form a sodium ion conductive film on the anode, which stabilizes deposition of sodium. We also find that sulfur remains interred in the carbon pores and undergo solid state electrochemical reactions with sodium ions.
Nature communications