There are a lot of problems with batteries: conflict mining, limited useful life, and difficulties transporting them when the stored energy is suddenly, catastrophically released. At the same time, we use them for all kinds of applications, in ways that are only increasing. 3D-printing startup Sakuu developed a solid-state battery that stands to solve some of these problems.

The idea of 3D printing batteries sounds crazy, but it results in a much safer battery. The Sakuu batteries are currently about 3mAH, or the equivalent of 3x AAA alkaline batteries.

The printed battery still uses a lithium metal anode, so mining is still required. Where traditional lithium-ion batteries use a liquid electrolyte to separate the anode and cathode, Sakuu uses a ceramic electrolyte, which is safer, preventing them from catching on fire. Sakuu claims to be able to print the metal and ceramic at the same time.

This isn’t a production-ready process yet. The printer is still a prototype, and Sakuu is working on scaling it up to an automated laser printer now.

Notably, Sakuu isn’t the only group working on solid state printed batteries. Blackstone Technology, announced in April that it printed its first working solid-state battery cell. They demonstrated it powering a small LED strip.

The benefits to printing batteries are safety, and packaging – instead of cylinders, or joined squares of flat batteries, it will be possible to print them in odd shapes, filling curves, and taking better advantage of space in the mechanical enclosure they’re powering.

3D printed batteries aren’t without some problems to overcome. The printers are slow, and early in development. Dendrites are little metal fingers that grow on the anode in batteries, increasing with each cycle, and reducing the life of the battery. Over time, the dendrite fingers pierce the electrolyte, causing fire.

There’s work being conducted at Harvard to supress dendrite growth by layering materials with varying stability between anode and cathode to catch the dendrites. So far, they claim 10,000 cycles on a battery without dendrites degrading the battery.

Dendrite suppression would be a huge gain for battery longevity everywhere, and it’s a technology we’re going to need. 3D printed technology is interesting, but even if it overcomes other factors, speed for production is still a concern.

You might say, with all these problems to be solved, what’s the point? The point is this: we are already a battery-reliant society in most of the world. Improvements that seem insignificant or unscalable today lead to improvements over all. Transport is a problem due to fire risk. Cycle life is a problem due to dendrites. By working on solutions for these problems today, batteries of the future may be safer and longer-lived before needing recycling.