American engineers learned how to 3D print lithium-ion batteries, ready to be used on devices. With this technology, they created the prototype of a bracelet with an LED and sunglasses with adjustable attenuation. In the future, this technology can allow complex devices to be created quickly with integrated batteries, say the authors of the article in ACS Applied Energy Materials.
3D printing is used not only for the rapid creation of plastic prototypes but also to create complex high-quality devices. However, until now only a part of the necessary components can be printed for a complete device, and chips and batteries must be manufactured in other ways.
Benjamin Wiley and colleagues at Duke University and the University of Texas have developed a method to create fully functional lithium-ion batteries using a 3D printer. Since the aim of the engineers was to create a simple and affordable technology, they chose an inexpensive 3D printer with an approximate value of US $ 250, which prints objects using layers (FDM). The printer is designed to print with polylactide, however, this material has an extremely low ionic conductivity and is not suitable for creating a battery, so the engineers had to modify the composition of the printing material.
Hacking a 3D printer
The researchers examined a variety of materials, measured their properties and established the following diagram. First, the printer prints a layer of conductive graphene filament for 3D printers. An anode of a mixture of polylactide, graphene and lithium titanate is printed on top of it, there is an electrolyte chamber printed from pure polylactide, and above it is a cathode of a mixture of polylactide, lithium manganese and multi-layer carbon nanotubes. Finally, the printer prints the second filament collector composed of the metal polymer.
The engineers have demonstrated the effectiveness of the method and have created two prototype devices with it. One is a ring-shaped bracelet with a curved battery that can power the LED for one minute. The second prototype is sunglasses with variable darkening.
More than a month ago, the founder of Defense Distributed, Cody Wilson, launched an online store of three-dimensional printed firearms plans. All designs are sold for US $ 10 dollars. This price includes a patented USB drive called Defense Distributed, which contains a file with drawings and shipping to the US. Only registered users who live in the USA can purchase the plans. For some states, the purchase is blocked, as local authorities banned the circulation and production of printed weapons.