NOVELTY - The thermoelectric device comprises a first electrode (102), a second electrode (104), a first electrolyte composition, a second electrolyte composition, a connector (105) comprising mobile cations and mobile anions, and an ion reservoir including first and second ion reservoirs. The first electrolyte composition is connected to the first electrode by being present in ionic contact. The second electrolyte composition is connected to the second electrode by being present in ionic contact. The connector is present in ionic contact with the first and second electrolyte compositions.    USE - The thermoelectric device is useful: for generating electric current and temperature difference to charge a capacitor; as a temperature sensor (all claimed), a thermoelectric generator for converting temperature difference into electricity and a thermoelectric cooler/Peltier cooler for pumping heat with electrical power; in renewable power sources such as geothermal or solar heat sources; and for large areas and low-temperature applications.    ADVANTAGE - The thermoelectric device can be economically manufactured in an environmentally friendly manner with high efficiency and thermoelectric figure of merit.    DETAILED DESCRIPTION - The thermoelectric device comprises a first electrode (102), a second electrode (104), a first electrolyte composition, a second electrolyte composition, a connector (105) comprising mobile cations and mobile anions, and an ion reservoir including first and second ion reservoirs. The first electrolyte composition is connected to the first electrode by being present in ionic contact. The second electrolyte composition is connected to the second electrode by being present in ionic contact. The connector is present in ionic contact with the first and second electrolyte compositions such that an applied temperature difference over the electrolyte compositions or an applied voltage over the electrodes facilitates transport of ions to and/or from the electrodes via the electrolyte compositions. The first electrolyte composition comprises an anionic polymer and/or the second electrolyte composition comprises a cationic polymer. The first and second electrodes comprise a material having a specific capacitance of 10-1000 F/g. The ion reservoir is placed at the junction between the first electrolyte composition and the first electrode and/or at the junction between the second electrolyte composition and the second electrode. The first electrode, second electrode, first electrolyte composition, second electrolyte composition and/or connector is applied by liquid deposition techniques. The thermoelectric device is arranged on a flexible solid substrate. The thermoelectric device further comprises a first leg (101) connected to the first electrode, and a second leg (103) connected to the second electrode. The first and second legs are coupled via the connector. The first leg is connected to the first electrode by being in ionic contact. The second leg is connected to the second electrode by being in ionic contact. The connector is present in ionic contact with the first and the second legs. The first ion reservoir is present in ionic contact with the first leg. The first electrode and the second ion reservoir are present in ionic contact with the second leg and the second electrode. The first and second ion reservoirs and the connector are spatially isolated from each other. The first leg comprises the first electrolyte composition for transporting cations from the connector to the first ion reservoir. The second leg comprises the second electrolyte composition for transporting anions from the connector to the second ion reservoir. The first electrode comprises a layer of a first electrically conductive polymer composition capable of being reduced which is present in ionic contact with the first ion reservoir or oxidized which is present in direct contact with the first ion reservoir. The second electrode comprises a layer of a second electrically conductive polymer composition capable of being oxidized which is present in ionic contact with the second ion reservoir or reduced which is present in direct contact with the second ion reservoir. The first ion reservoir comprises the mobile cations. The first electrode and the second ion reservoir comprise the mobile anions. The connector comprises a cation and anion transporting composition in ionic contact with the first and the second legs. A polymeric electrolyte is configured as an ion transporting material in the thermoelectric device. A conductive polymer is reduced and/or oxidized in the electrodes of the thermoelectric device. INDEPENDENT CLAIMS are included for:    (1) a method for generating electric current; and    (2) a method for generating a temperature difference.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a thermoelectric generator.    First leg (101)    First electrode (102)    Second leg (103)    Second electrode (104)    Connector. (105)