Surface Modification of a Li[Ni0.8Co0.15Al0.05]O2 Cathode using Li2SiO3 Solid Electrolyte

Li2SiO3 was used as a coating material to improve the electrochemical performance of Li[Ni0.8Co0.15Al0.05]O-2 center dot Li2SiO3 is not only a stable oxide but also an ionic conductor and can, therefore, facilitate the movement of lithium ions at the cathode/ electrolyte interface. The surface of the Li2SiO3-coated Li[Ni0.8Co0.15Al0.05]O-2 was covered with island-type Li2SiO3 particles, and the coating process did not affect the structural integrity of the Li[Ni0.8Co0.15Al0.05]O-2 powder. The Li2SiO3 coating improved the discharge capacity and rate capability; moreover, the Li2SiO3-coated electrodes showed reduced impedance values. The surface of the lithium-ion battery cathode is typically attacked by the HF-containing electrolyte, which forms an undesired surface layer that hinders the movement of lithium ions and electrons. However, the Li2SiO3 coating layer can prevent the undesired side reactions between the cathode surface and the electrolyte, thus enhancing the rate capability and discharge capacity. The thermal stability of Li[Ni0.8Co0.15Al0.05]O-2 was also improved by the Li2SiO3 coating.