A power cell (100A) has an electrolyte that includes a reodox pair comprising cerium. The electrolyte in preferred cells is an acid electrolyte that comprises a element ion complexed by an organic acid or a chelating agent, and contemplated electrolytes may further include a compound that reduces the hydrogen overpotential. Where the power cell comprises a plurality of cells (100B), preferred configurations may include glassy carbon as bipolar electrolytes.