The electrolyte and the electrochemical cell define the environment and boundary conditions in which reactions occur. While electrodes determine where the reaction happens, the electrolyte controls how it happens, and the cell design governs mass transport, solution resistance (Rs), and product pathways.

Solvent choice, supporting electrolyte concentration, pH, atmosphere, and temperature all influence potential window, conductivity, interfacial structure, and reaction stability. At the same time, cell geometry — including electrode spacing, compartment design (open, sealed, H-type, flow), and convection conditions — directly affects iR drop, diffusion behavior, and reproducibility.

This section explores how electrolyte composition and cell configuration must be matched to experimental objectives, ensuring that measured data reflect controlled system behavior rather than uncontrolled boundary variations.