Abstract: The invention provides a high temperature electrochemical power storage cell which has a cathode compartment containing a molten alkali metal aluminium halide molten salt electrolyte and a cathode which comprises an electronically conductive electrolyte-permeable porous matrix. The matrix has, dispersed therein, an active cathode substance THal.sub.2 in which Hal is the halide of the electrolyte and T is a transition metal selected from Fe, Ni, Co, Cr, Mn and mixtures thereof, the matrix being impregnated with said molten electrolyte. The matrix comprises the transition metal T of the active cathode substance in porous form and the cathode includes, embedded in the matrix, a metallic current collector having a coating thereon which is chemically and electrochemically inert in the cell environment and is electronically conductive, the metal of the current collector being no more noble than any transition metal of the active cathode substance.