TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Construction: The active or other components include a mobile reactant, the flow (14) of which into the chemical reaction zone is at least locally inhibited as soon as positive pressure builds up (or could build up) inside the container, specifically when the temperature within the container is at least locally above or below a threshold value. Reaction inhibition is preferably at least partially reversible. Inhibition is specifically carried out using (a) a coating on the electrodes which at least locally modulates the reaction and/or (b) a separator layer (12) between the electrodes, which at least locally inhibits flow of at least one reactant along the layer. The separator layer is of porous inorganic material, preferably containing particulate material(especially polymer and/or wax) fusing at or above a threshold temperature to block the pores or reduce the pore size. The pores of the separator specifically fill with the mobile reactant (due to capillary action), so that only a relatively small fraction of the total amount of this reactant in this device is present outside the pores. Alternatively the separator has little or electrical conductivity; consists of an at least partially permeable carrier (specifically of organic material, especially a non-woven of polymeric material (particularly polyethylene terephthalate); and is coated on one side with inorganic material, which is preferably ion-conductive in the -40 to +200 degrees C temperature range and in the form of particles of maxiumum diameter below 100 nm.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The device includes at least one electrode (specifically a cathode) containing (a) a complex lithium (Li) phosphate compound of formula LiMPO4 (I), preferably having an olivine structure (especially a super-ordered olivine structure) and/or (b) one or more of Li manganates (specifically spinel-type LiMn2O4), Li cobaltates (specifically LiCoO2), Li nickelates (specifically LiNiO2) and/or Li mixed oxides containing manganese, cobalt and nickel.M = first-row transition metal cation, preferably manganese (Mn), iron (Fe), nickel (Ni) and/or titanium (Ti), especially Fe.The separator is coated on one side with inorganic material(s) selected from oxides, phosphates, sulfates, titanates, silicates and/or aluminosilicates of zirconium, aluminum and/or Li, especially zirconia (ZrO2).    TECHNOLOGY FOCUS - POLYMERS - Preferred Materials: The device includes a separator (12) based on a polyethylene terephthalate non-woven. EXAMPLE - No relevant example given.