As a new high-voltage cathode candidate for post 4 V cathodes, ordered-olivine LiCOPO4 and fluoride phosphate, Li2CoPO4F were synthesized by solid-state reaction. Their structures were identified by neutron diffraction. The 5 V 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. (c) 2005 Elsevier B.V. All rights reserved.