Seamless Stitching of Redox Windows to Enable High‐Voltage Resilient Solid Sodium Ion Batteries

Abstract

While sulfide solid electrolytes such as Na11Sn2PS12 can allow fast transport of Na+ ions, their utilization in solid sodium ion batteries is rather unsuccessful since they are not electrochemically compatible to both high‐voltage cathodes and sodium metal anode. In this work, we devise an effective approach toward realizing solid sodium ion batteries, using the Na11Sn2PS12 electrolyte and slurry‐coated NASICON‐type Na3MnTi(PO4)3@C as high‐voltage cathode, highly beneficial for low processing cost and high content/loading of active cathode matter. We report that through significantly improved integrity of electrolyte‐cathode interface, such solid sodium ion batteries can deliver outstanding cycling and rate performance, with a charge voltage resilience up to 4.1 V, a high cathode discharge capacity of 128.7 mAh g−1 against the Na3MnTi(PO4)3@C in cathode is achieved at 0.05 C, and capacity retention ratio of 82% with a rate of 0.1 C is realized after prolonged cycling at room temperature. Besides, we demonstrate that such a solid sodium ion battery can even perform at a sub‐zero Celsius temperature of −10°C, when the conventional control cell using liquid electrolyte completely fail to function. This work is to offer a dependable avenue in engineering next generation of safe solid ion batteries based on highly sustainable and much cheaper material resources.