Electrochemically Stable Sodium Metal-Tellurium/Carbon Nanorods Batteries

Electrochemical metal cells utilizing tellurium and sodium chemistry are being extensively explored for developing advanced high-performance batteries. The daunting challenges, however, still remain with low rate capability/volumetric capacity, unclear redox reaction processes, and the notorious sodium dendrites. Here, a cell design that features a novel Te/carbon nanorods cathode and a tailored ether-based electrolyte is reported. It is the first report of Na metal-Te full batteries with performance comparable to those of reported Na-S and Na-Se batteries at low ratings. By using the semimetal Te instead of the insulating S or Se, the Na-Te batteries actually outperform reported Na-S and Na-Se batteries at high ratings. Ab initio molecular dynamics simulations, UV-vis spectrum, ex situ X-ray photoelectron spectroscopy, and scanning electron microscopy results clearly reveal a three-step redox process and stability of the Na metal-Te cells. These comprehensive results demonstrate the feasibility of practical Na metal-Te batteries with high volumetric energy density and a viable cell fabrication cost.