Researchers gain fresh insights into battery electrode

The new findings explain the high power and long cycle life of such batteries, the researchers claim.

The findings, which appear in a paper in Nano Letters, were co-authored by MIT postdoc Jun Jie Niu, research scientist Akihiro Kushima, professors Yet-Ming Chiang and Ju Li, and three others.

The electrode material studied, lithium iron phosphate (LiFePO4), is considered a promising material for lithium-based rechargeable batteries and has been demonstrated in applications ranging from power tools to large-scale grid storage.

The MIT researchers found that inside this electrode, during charging, a solid-solution zone (SSZ) forms at the boundary between lithium-rich and lithium-depleted areas, the region where charging activity is concentrated, as lithium ions are pulled out of the electrode.

Li said in a statement that this SSZ has been theoretically predicted to exist, but the MIT team observed it directly for the first time in transmission electron microscope (TEM) videos taken during charging.