Non-aqueous redox flow batteries

A non-aqueous redox flow battery (RFB) comprising:

• a positive compartment in which a positive electrode is placed and in which a non-aqueous liquid positive electrolyte is made to flow;
• a negative compartment in which a negative electrode is placed and in which a non-aqueous liquid negative electrolyte is made to flow;
• an ion exchange membrane placed between the positive compartment and the negative compartment;
• wherein:
• said non-aqueous liquid positive electrolyte comprises a solution of copper triflate or tetrafluoroborate complexes [Cu(I) or Cu(II)] in at least one organic solvent;
• said non-aqueous liquid negative electrolyte comprises a solution of at least one benzothiadiazole having general formula (I):
• wherein:
• R1 and R2, equal or different from each other, represent a hydrogen atom;
• or represent a C1-C20 alkyl group, linear or branched, saturated or unsaturated;
• or represent a —O—R3 group wherein R3 is selected from C1-C20 alkyl groups, linear or branched, saturated or unsaturated, or R3 is selected from —(CH2)nCOOR4 groups wherein R4 is selected from C1-C20 alkyl groups, linear or branched, saturated or unsaturated, and n is an integer comprised between 1 and 10, or R3 is selected from —(CH2)nOR4 groups wherein R4 and n have the same meanings reported above, or R3 is selected from —(CH2CH2O)nR4 groups wherein R4 and n have the same meanings reported above, or R3 is selected from —(CH2)nCN groups wherein n has the same meanings reported above, or R3 is selected from —(CH2)nNR4R5 groups wherein R4 and n have the same meanings reported above and R5 is selected from C1-C20 alkyl groups, linear or branched, saturated or unsaturated, or R3 is selected from —(CH2)nCONR4R5 groups wherein R4, R5 and n have the same meanings reported above, saturated or unsaturated, or R3 is selected from —(CH2)nSi(R4)3 groups wherein R4 and n have the same meanings reported above, or R3 is selected from —(CH2)nSi(OR4)3 groups wherein R4 and n have the same meanings reported above;
• provided that at least one of R1 and R2 is different from hydrogen and at least one of R1 and R2 is in position 2 of the phenyl;
• in at least one organic solvent.