A potassium secondary cell was designed employing a potassium anode and a Prussian blue (PB)-based cathode. The electrolyte solution for the nonaqueous battery was 1M KBF4 in 3:7 EC/EMC. The potassium battery designed had some valuable advantages in comparison with similar lithium batteries. The cell design is simple, and both the material used and the procedure needed for the cell fabrication are cheaper. In addition, the cell has an excellent cyclability for more than 500 reversible cycles. There is only a negligible capacity fade for the battery performance at elevated temperatures. Moreover, the chemical diffusion coefficient of K+ in the cell is higher than that of Li+ in lithium batteries, which is due to a smaller Stoke’s radius of K+ in electrolyte solution (solvated ions). The results obtained from the experimental measurements and the prospective of this rechargeable cell suggest it as a promising alternative to lithium secondary cells.