What primarily defines the performance of an electrochemical cell?

The performance of an electrochemical cell is primarily defined by the concentration of the reactants because this parameter directly affects the cell's voltage, current, and overall efficiency. According to the Nernst equation, the cell potential is influenced by the concentration of the reactants and products involved in the electrochemical reactions. Higher concentrations of reactants typically lead to increased reaction rates and greater voltage output, ultimately enhancing the cell's performance.

While purity of the reactants can also influence the efficiency of the cell by reducing side reactions or enhancing conductivity, the concentration plays a more critical role in determining the extent of the electrochemical reactions that occur. The type of container may provide physical support for the cell but does not directly affect its electrochemical performance. Ambient temperature affects the kinetic energy of the molecules and can influence reaction rates, but the concentration of reactants remains a fundamental factor in defining cell performance.