This is a guest blogpost by Aya Nader.
Using two dimensional oxide anodes with a controlled number of atomic layers is an effective way to prolong the cycle life of Na (sodium) ion batteries, scientists from Saudi Arabia have revealed in a new research. The advancement carries great potential for grid storage.
Batteries normally have two electrodes: anode and cathode. Anodes can be manufactured from different materials, including oxides, sulfides, and phosphides. Usually, oxide anodes such as tin monoxide (SnO) go through massive volume change and degrade significantly after use, seriously shortening the life cycle of a sodium ion battery. Typically, researchers mixed the oxide anodes with carbon-based materials such as graphene to mitigate this large volume change.
“However, the new approach stacks few atomic layers of two dimensional SnO anodes to suppress this volume change, making batteries that last more than 1000 cycles,” explains Husam N. Alshareef, principal investigator of the study and professor of functional nanomaterials and devices at King Abdullah University of Science and Technology (KAUST), Saudi Arabia.
They used two dimensional materials made up of sheets of atoms, or atomic layers, stacked on top of each other. The thinnest SnO nanosheet anodes (two to six SnO monolayers) exhibited the best performance according to their study, published in the journal Nano Letters. As the average number of atomic layers in the anode sheets increased (beyond 10), the battery performance degraded proportionally and remarkably, the study found.
Now, the researchers are trying to combine the SnO anodes with suitable cathode materials to create full cell sodium ion batteries. The idea is to use these batteries to power small devices, such as phones and other electronic devices, and test their cycling performance in more realistic conditions.
In addition, the scientists plan to try charging up the batteries using solar power. Practically, sodium ion batteries are candidates to replace lithium ion batteries, especially in stationary storage applications, as sodium is cheaper and more available than lithium.
“Our progress using SnO anodes has resulted in stable sodium ion batteries that offer competitive capacity for grid scale applications,” says Fan Zhang, PhD researcher and lead author of the study. “This is exciting because it means a more effective storage solution has been identified for grid storage applications.”