Magnesium oxide powder (CAS number 1309-48-4) is a metal oxide that consists of Mg2+ and O2- ions in a cubic crystal lattice. With a large bandgap of approximately 7.8 eV, MgO serves as a hole-blocking layer in perovskite solar cells and dye-sensitized solar cells. MgO effectively blocks charge recombination during the charge transport process from the perovskite layer to the negative electrode. This results in an 11% increase in power conversion efficiency when a thin MgO layer is employed. Additionally, MgO is a superior substrate compared to SnO2 for the growth of perovskite (CsPbIBr2), reducing the formation of interface δ-phase perovskite.
Magnesium oxide powder also finds its application in lithium sulfur (Li-S) batteries. MgO can efficiently capture dissolved polysulfides, thereby enhancing the reversibility of Li-S battery cells. MgO-functionalized Li-S battery cells demonstrate an initial discharge capacity of 980 mAh/g, compared to 729 mAh/g in control cells. Furthermore, after 200 cycles, the capacity retention remains at 78.3%.