The substitution of Co for Fe in Pnma-Li2FePO4F i.e. Li2Fe1−xCoxPO4F (x = 1/8, 2/8, 3/8, 4/8, 5/8, 6/8, 7/8) are stable enough as new cathode materials and with the concentration of Co increases the discharge potential of the materials can increase.
The Li–Mn–O phase diagram as a function of the chemical potential of Li and O and the pH.