A composite cell plate can include a polymer element laterally mated and interlocked, at a plurality of engagement points, with a resilient metal element. The cell plate can be used in an electrochemical cell. A method of forming a cell plate can include fitting a polymer element to a resilient metal element at a plurality of engagement points, and expanding the polymer of the polymer element such that the polymer element and the resilient metal element engage and interlock at the engagement points.