To demonstrate the technology, the scientists printed a working heart-shaped battery onto a cup, another onto a paper eyeglass and even one in the form of the letters "PRISS", all of which were capable of powering LEDs.
Conventional Li-on batteries come in set shapes and sizes because of the way they're constructed. You need separator membranes to prevent the electrodes within the battery from coming into contact with each other. And the battery as a whole needs a robust case that doesn't leak because of the combustible liquid electrolyte within.
The researchers achieved their breakthrough by eliminating the need for traditional separator membranes. To do this, they created printable solid-state electrolytes that function as an ion-conducting medium.
"The new solid-state electrolytes are printable and also solidify after exposure to UV irradiation, eventually acting as an alternative separator membrane," Sang-Young Lee, a Professor at the Ulsan National Institute of Science and Technology (UNIST) in South Korea, told Gizmag.