After 2 years Covid-hiatus, the open day of Saarland University and the INM – Leibniz Institute for New Materials returned full swing on May 21st. Our team was all amped up to tell our visitors all about energy materials, water remediation, and why there is no cooler profession than being a material scientist / chemist / engineer. We discussed what an old factory ruin (of the “Blaufabrik”) in Sulzbach has to do with sodium-ion car batteries and why there is Lithium in Saarland mine water (and how to get it out). Naturally, most people were interested in our “build your own battery” station. This year, the age span from 4 to 70 and the CR2032 coin cells were equipped with Kynol activated carbon, 1 M aqueous potassium iodide solution, glass fiber separator, and a lot of positive energy. We charged them up to 1.2 V and powered a small fan to show to people: making batteries may be magical but is no mystery. I am very grateful to my wonderful team, especially Dr. Samantha Husmann, Dr. Emmanuel Pameté, Dr. Sarah Saleem, Stefanie Arnold, Behnoosh Bornamehr, Amir Haghipour, Mohammad Torkamanzadeh, and of course Christine Hartmann and Petra Lück for their support to make this day a resounding and wonderful success. And yes, our science Lego models were a big hit with many visitors (independent of their age). I am already excited about next year’s open day! Ready, set… go!