Probing the electrochemical evolutions of Na–CO2 nanobatteries on Pt@NCNT cathodes using in-situ environmental TEM

Na–CO batteries possess many virtues including low cost, abundant sodium-containing resources, and environment-friendly nature. Understanding the electrochemical reaction processes is fundamental for battery design and performance enhancement of Na–CO batteries. Using in-situ environmental transmission electron microscopy in CO gas, we directly probed the morphology evolution and phase transformations of the charge and discharge products with single Pt atom and nitride doped carbon nanotube (Pt@NCNT) cathode in a Na–CO nanobattery. The discharge reaction produces NaCO and carbon, which subsequently decomposed into Na ions and CO during charge. The discharge rate was boosted with the help of the single-atom Pt catalyst. Our work provides a fundamental insight into the governing principles on Na–CO battery design for better energy storage devices.