The present invention relates to an aqueous polymer electrolyte comprising: a) water in a range of ≥ 5 wt% to ≤ 95 wt%, b) a metal ion component comprising a metal cation selected from the group consisting of Li+, Na + , K + , Mg 2+ , Al 3+ , Ca 2+ , Fe 2+ , Fe 3+ and Zn 2+ , and c) a polymer component comprising repeat units according to the following formula (I) : -[C(X 1 )(X 2 )-C(Y 1 )(Y 2 )-Z]- wherein: X 1 , X 2 are selected, the same or independently from the other, from the group consisting of -H, -OH, -CH 3 , -NH 2 , -CH 2 OH and -C 6 H 9 (OH) 2 ; Y 1 , Y 2 are selected, the same or independently from the other, from the group consisting of -H, -CH 3 , -NC 4 H 6 O, -CONH 2 , -COOH, -COO - , C 6 H 10 SO 2 O - and -C 6 H 10 SO 2 OH; Z is an optional element selected from the group consisting of -O-, -CH2~, -CO- and methyl cellulose; wherein the metal ion component and the polymer component together amount to a content range of ≥ 5 wt% to ≤ 95 wt%, all wt% referring to a total amount of the aqueous polymer electrolyte of 100 wt%.