The thermoelectric power of the Li+/Li couple was measured in a LiCl-KCl eutectic melt at 633-773 K. The obtained value, 0.089 mV K-1, gives the single electrode Peltier heat for the reaction Li+ + e(-) reversible arrow Li as - 5.8 kJ F-1 at 673 K (endothermic cathodic reaction). The single electrode Peltier heat for the reaction 1/2H(2) + e(-) reversible arrow H-in a molten LiCl-KCl-LiH system has been calculated using the temperature dependence of the equilibrium potential of the H-2/H-couple measured with reference to the Li+/Li potential, which gives 5.8 kJ F-1 (exothermic cathodic reaction) under the condition of hydrogen pressure of 1.0 atm, H- ion concentration of 0.01 (anion fraction) and 673 K. The single electrode Peltier heats for formation of Pd-Li alloys have been also evaluated. (C) 2004 Elsevier Ltd. All rights reserved.