The present invention relates to a process for the preparation of compounds of general formula (I) Lia-bM1bV2-cM2c(PO4)x  (I) wherein M1, M2, a, b, c and x have the following meanings: M1: Na, K, Rb and/or Cs, M2: Ti, Zr, Nb, Cr, Mn, Fe, Co, Ni, Al, Mg and/or Sc, a: 1.5-4.5, b: 0-0.6, c: 0-1.98 and x: number to equalize the charge of Li and V and M1 and/or M2, if present, wherein a-b is >0, to a compound according to general formula (I) as defined above, to spherical agglomerates and/or particles comprising at least one compound of general formula (I) as defined above, to the use of such a compound for the preparation of a cathode of a lithium ion battery or an electrochemical cell, and to a cathode for a lithium ion battery, comprising at least one compound as defined above.