The invention concerns an electrochemical cell in thin films and aqueous electrolyte, with an emissivity that varies as a function of an applied control voltage. It is formed of the following flexible elements, superimposed and respectively in intimate contact:
a first current collector (11) in electrically conducting material and intended to be connected to a first potential of the control voltage,
a porous counter electrode (12) formed of a mixture of PVDF-HFP, PEO and a powder of a compound comprising complementary ions of an insertion material,
a porous separator (13) formed of a mixture of PVDF-HFP and PEO,
a second current collector (14) in electrically conducting material, intended to be connected to a second potential of the control voltage and capable of being traversed by ions,
a porous electronic conduction layer (15) formed of a mixture of PVDF-HFP, PEO and a powder of an electrically conducting material,
a porous active layer (16) formed of a mixture of PVDF-HFP, PEO and a powder of an insertion material.