As a new high-voltage cathode candidate for post 4V cathodes, ordered-olivine LiCoPO4 and fluoride phosphate, Li2CoPO4F were synthesized by solid-state reaction. Their structures were identified by neutron diffraction. The 5V discharge profiles were demonstrated using coin-type cells. Two important issues for commercial use, metal dissolution and oxygen release at elevated temperatures, were also tested with an atomic absorption spectrophotometer and differential scanning calorimeter, respectively.