Aqueous hydrogel electrolyte systems with wide electrochemical stability window

An electrochemical cell comprising:

• (a) an anode comprising sulfur;
• (b) a cathode;
• and
• (c) an aqueous hydrogel electrolyte comprising between about 25 m and about 50 m of at least one metal salt, at least one solvent comprising between about 1% and about 100% water by weight, and at least one hydrophilic polymer so as to form a hydrogel having a hydrophilic polymer matrix, wherein the anode is capable of forming decomposition products, wherein the decomposition products comprise one or more metal polysulfides, wherein the decomposition products are phase-separated from the electrolyte, and wherein the aqueous hydrogel electrolyte floods the cell so as to define an internal pressure and a capacity retention of the cell of at least 62% over 200 cycles at 1 C.