3 a and 3 b can for example be platinum (Pt), chromium (Cr), gold (Au) or titanium (Ti) based. [0017] The positive electrode 4 can be formed by LiCoO2, LiNiO2, LiMn2O4, CuS, CuS2, WOySz, TiOySz, V2O5 or V3O8 and lithium forms of these vanadium oxides and metal sulfides.