ELI5: What is the difference between solid-state and lithium-ion batteries

A solid-state battery is like a cookie made entirely of hard chocolate, while a lithium-ion battery is like a cookie with a gooey chocolate center.

Imagine a battery is like a cookie that gives your toys or phone power.

• Lithium-ion batteries (the gooey cookie) are what we use in most of our phones, tablets, and electric cars today. They have a squishy, liquid or gel-like part inside, called the electrolyte, that helps the power move around. Think of it like melted chocolate in the middle of your cookie. This melted chocolate can sometimes leak or catch fire if the cookie gets too hot or damaged.

• Solid-state batteries (the hard chocolate cookie) are different because the squishy part is replaced with a solid material, like hard chocolate. This means there's no liquid to leak or catch fire, making them safer. They can also hold more power in the same space, like having a cookie packed with more chocolate chips!

• They're harder and more expensive to make right now.
• Imagine trying to build a whole cookie out of perfectly solid chocolate that still lets the power (chocolate flavor) flow smoothly – it's tricky!