The electrochemical performance of polymer lithium-ion batteries was studied as a function of the hexafluoro propylene (HFP) content in the PVDF–HFP copolymers used as electrode binders and separator membranes. The HFP content in electrode binders was found to have a significant impact on the cycle life performance at elevated temperatures. Best results were achieved with a 5% HFP level, where good cycle life was demonstrated at 60°C, combined with good rate capabilities and low temperature performance. In contrast to electrode binders, the HFP content in separator membranes was found to have no significant impact on cell performance.