Electrochemical and thermal properties of Co3(PO4)2- and AlPO4-coated LiNi0.8Co0.2O2 cathode materials were compared. AlPO4-coated LiNi0.8Co0.2O2 cathodes exhibited an original specific capacity of 170.8mAhg−1 and had a capacity retention (89.1% of its initial capacity) between 4.35 and 3.0V after 60 cycles at 150mAg−1. Co3(PO4)2-coated LiNi0.8Co0.2O2 cathodes exhibited an original specific capacity of 177.6mAhg−1 and excellent capacity retention (91.8% of its initial capacity), which was attributed to a lithium-reactive Co3(PO4)2 coating. The Co3(PO4)2 coating material could react with LiOH and Li2CO3 impurities during annealing to form an olivine Li x CoPO4 phase on the bulk surface, which minimized any side reactions with electrolytes and the dissolution of Ni4+ ions compared to the AlPO4-coated cathode. Differential scanning calorimetry results showed Co3(PO4)2-coated LiNi0.8Co0.2O2 cathode material had a much improved onset temperature of the oxygen evolution of about 218°C, and a much lower amount of exothermic-heat release compared to the AlPO4-coated sample.