The effect of ZnO and MgO coatings by a sono-chemical method, on the stability of LiMn _1.5Ni _0.5O ₄ as a cathode material for 5 v li-ion batteries

This work demonstrates the effect of coating LiMn _1.5Ni _0.5O ₄ with MgO and ZnO by a sono-chemical method. It was found that the sonochemical process results in a coating that serves as a buffer, yet allows the easy transport of Li ions to and from the active mass. Both the ZnO and MgO coatings modify the particles' surface chemistry and help to inhibit the dissolution of Mn and Ni ions from the active mass into the solution phase at elevated temperatures and thus managed to improve the stability of LiMn _1.5Ni _0.5O ₄ as an high voltage cathode material. MgO was found to be more effective than ZnO in this regard. The MgO coated cathodes demonstrated better electrochemical performance than the uncoated material. Lastly, the ZnO-coated material indicated a reduction in thermal stability in standard solutions, while the MgO coating did not affect the materials thermal stability.