Zhaoxin Yu, The Pennsylvania State University
A Super High Conducting Solid-State Electrolyte for Room-Temperature Sodium-Ion Batteries
Written by Armin VahidMohammadi
Beyond a doubt, battery systems beyond lithium-ion are one of the hottest research areas due to limited resources of lithium metal in the world and many different safety issues that are associated with current lithium ion batteries. One of the most promising candidates for lithium is sodium (Na). In the last talk of the morning session of the ES1 symposium, Zhaoxin Yu from The Pennsylvania State University presented work on solid-state sodium-ion batteries. The study introduced sulfide Na-ion solid state batteries where the system uses an electrolyte containing a mixture of Na, phosphorous, arsenic, and sulfur. Their electrolyte with the composition of Na3P1-xAsxS4 is a pure ionic conductor. It was explained that the As-substitution is a main reason for improved performance in their system and he went over the mechanism that is existing behind this change in the composition. Two factors were explained to affect the ionic conductivity of the solid-state electrolyte. One of them was the lattice expansion, and the other one was the sulfur and phosphorous bonding with Na atom. In low concentrations the lattice expansion is the dominating factor that increases the conductivity and in higher concentrations the stronger bonding between the sulfur and Na is the parameter that results in a decrease in the ionic conductivity. They had studied the moisture stability of their material as well.