Electrochemical cell

A method of making a cathode suitable for a secondary electrochemical cell which comprises activating or preconditioning one or more oxides which have a spinel-type or oxospinel-type structure according to the formula

• AB.sub.2 O.sub.4
• wherein:
• at least one of A or B is a transition metal;
• and
• each of A and B is a di-, tri- or tetravalent cation of a metal selected from the group consisting in Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mg and Al to form therefrom a cathode which is in the form of a stable three dimensional framework structure, the structure, when in a secondary electrochemical cell with a compatible electrolyte and a compatible anode, being capable of reversible charge/discharge reactions while being stable with regard to other physical or chemical changes in structure the activation or preconditioning being electrical, and comprising subjecting the starting material to a plurality of charge/discharge cycles in an electrochemical cell wherein the starting material forms the cathode, and is coupled via a compatible electrolyte with a compatible anode, the electrolyte having an intrinsic electrolysis voltage threshold greater than the threshold voltage for activation of the cathode.