What is a primary reason that a cell cannot be electrically recharged?

A primary reason that a cell cannot be electrically recharged is that the reactions involved are not reversible. In electrochemical cells, certain types, such as primary cells (like alkaline batteries), utilize chemical reactions that proceed in one direction. Once the reactants are converted into products during discharge, the chemical pathways cannot be reverted to regenerate the original materials needed for another discharge cycle. This irreversibility arises from the specific chemistry involved, which often leads to a stable product that does not easily convert back to its original reactants.

This characteristic defines primary batteries, making them suitable for single-use applications where high energy density is needed without the requirement for recharging. In contrast, rechargeable cells, or secondary cells, employ reversible reactions that allow the flow of current to be reversed, enabling the original reactants to be restored.

Understanding this concept helps clarify the limitations of certain electrochemical systems and emphasizes the importance of reaction reversibility in the design and application of batteries.