Effect of AlPO4 coating on the electrochemical properties of LiNi0.8Co0.2O2 cathode material

The AlPO4-coated layered LiNi0.8Co0.2O2 samples were prepared, and characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, differential scanning calorimetry, X-ray photoelectron, electrochemical impedance spectroscopy and electrochemical test. It is found that the AlPO4 layer is amorphous with the thickness of 5 nm. The AlPO4-coated LiNi0.8Co0.2O2 cathode material has increased reversible capacity, stabilized cycling performance, improved high-temperature performance, which are attributed to can minimize the harmful side reactions within the batteries by placing a protective barrier layer between the oxidizing cathode material and liquid electrolyte and the decrease of electrochemical impedance.