As a part of my RET experience at Notre Dame, I’m tasked with creating activities which embody concepts related to the research I’ve done in the program. I though I’d share what I’d come up with this summer.
One of the most important aspects of research for me is the ability to see where science is heading and then translate that information into experiences that my students can explore in my classroom. There are always limits to the translatability of research into the classroom; constraints on equipment are often the limiting factor. This summer’s work with Li-ion cells has been a challenge, but I feel good about the outcome.
My goal was to attempt to mimic the solid-state electrolyte we use in the creation of the Li-ion batteries. In the lab this meant making nanopowder, heating, pressing, sintering, loading with cathode and anode material, and then testing. I knew this cycle of work would not be useful for my students, so instead I focused on the fundamentals; what did I want my students to leave the experience with in terms of understandings? In essence, I want them to:
- Understand that batteries store chemical energy, which is converted into electrical energy through a redox process.
- Understand that different cathode and anode materials will result in different electrical potentials and be able to suggest alternative cathode/anode combinations to improve a batteries voltage output.
- Use simple circuits in conjunction with electrochemical cells to do work.
- Describe the nanoscale processes occurring during a batteries discharge and operation.
My solution was an activity that removed the traditional mess involved with the creation of wet-cells in electrochemistry. Instead of using aqueous solutions of ionic salts and porous cups, I chose to use the wonderful conductive dough developed at the University of St. Thomas (check out their Squishy Circuits TED Talk to get an idea of the possibilities that this dough can provide!) to serve as the electrolyte. The dough is pliable and lasts for several weeks unrefrigerated and is made of simple ingredients, keeping the cost of this lab low.
Students use the dough to make a modified aluminum-air battery, commonly known as the “burrito battery“. The construction of the battery is simple, and can be done in less than 15 seconds, leaving more time for students to discuss applications and optimize solutions to problems (such as to light a particular color of LED).
While this lab activity is quite structured, there are many opportunities for modification to make the lab more open-ended. Consider the following questions that students could answer using the basic setup provided within the lab:
- What is the relationship between dough thickness and battery performance?
- Is carbon the only acceptable cathode material?
- How do you maximize current from this cell?
- How do you maximize voltage from this cell?
In addition, I modified a section of CK-12’s opensource text for use specifically with this lab as well as created a detailed lesson plan if you’d like to try this lab activity with your students. If you do give it a whirl, please let me know how it goes!