Electrolyte concentration effects on Zn-Cu galvanic cells: Powering LEDs through redox optimisation

Abstract

This study investigated the effect of electrolyte concentration on the performance of Zn-Cu galvanic cells and their ability to power LEDs with different voltage requirements. Three half-cells were constructed using Zn and Cu electrodes, each immersed in electrolyte solutions of different molarities. Each configuration was tested individually and in series to assess voltage output and LED activation. Results showed that higher molarity solutions produced slightly higher voltages, and connecting cells in series increased total voltage. While single cells could not power any LEDs, series connections of two and three cells successfully powered low- and high-threshold LEDs, respectively. These findings highlight key redox and electrochemical principles relevant to practical energy applications. Electrochemical systems based on similar reactions are essential in medical implants, electric vehicles, and next-generation energy storage technologies, where efficient and reliable power delivery is at the heart of these applications.