Pseudo-Solid-State Bipolar Zn–I ₂ Batteries: A Laboratory Experiment for Teaching Ionic Transport and Bipolar Cell Configuration in Advanced Solid-State Batteries

The rapid expansion of the battery industry has created an urgent need for graduates equipped with modern knowledge of solid-state battery systems. However, most teaching laboratories still rely on simple liquid-electrolyte cells. Herein, we introduce a three-session (∼13 h) graduate laboratory module based on an accessible Zn–I2 platform that models key features of solid-state electrolytes and bipolar battery configurations; both are essential for next-generation solid-state battery design. Students begin by synthesizing a pseudo-solid-state single-ion hydrogel electrolyte and comparing its ionic conductivity and cation transference number to those of a traditional liquid electrolyte. These results are then used to introduce Sand’s time analysis for dendrite initiation and to correlate transference number with metal anode deposition morphology. Using the same hydrogel electrolyte, students assemble monopolar, 2-stacked and 3-stacked bipolar Zn–I2 coin cells, measure open-circuit voltages, perform LED-lighting demonstrations, and conduct galvanostatic cycling to quantify output voltage and energy-density improvements from bipolar stacking. Pre- and postlab exercises, together with detailed safety guidelines reinforce both conceptual understanding and safe experimental practices. These hands-on experiences are expected to help cultivate the skilled workforce needed for emerging solid-state battery industries.