Ion-conducting polymer electrolyte films based on poly (ethylene oxide) (PEO) complexed with potassium bromate (KBrO3) are prepared by a solution-cast technique. Several experimental techniques such as differential scanning calorimetry (DSC), dc-conductivity and transference number measurements are employed to characterise this polymer electrolyte system. The conductivity–temperature plots show two regions in the temperature range of study and transport number data which indicate that the charge transport in this electrolyte system is predominantly due to ions. Using these polymer electrolyte films, solid-state electrochemical cells are fabricated and their discharge characteristics are examined for a constant load of 100kΩ. Several cell parameters associated with the cells are evaluated and reported.