Holographic Microbattery

Creation of miniature devices is on the rise. Many miniaturized devices like medical implants, flying insect-like robots, sensors, wireless transmitters and tiny cameras have been invented.

To give you an idea of the scale, this image shows the battery’s electrodes in a 2mm by 2mm square on a glass wafer sitting on a fingertip. (Image courtesy University of Illinois)

Recently, a team of engineers at the University of Illinois, Urbana-Champaign demonstrated that porous, three-dimensional electrodes can boost a lithium-ion microbattery’s power output by three orders of magnitude, as first reported in Chemical & Engineering News. But now the team has gone a step further, and has optimized the electrode structure with holograms, the three-dimensional interference patterns of multiple laser beams, in order to generate porous blocks that could used as a sort of scaffolding for building electrodes.

The result: a holographic microbattery that’s only 2mm wide and 10 micrometers thick, with an area of 4mm squared, and 12% capacity fade. The researchers said it’s compatible with existing fabrication techniques, and ideal for large-scale on-chip integration with all kinds of microelectronic devices, including medical implants, sensors, and radio transmitters. Batteries like this could power implants small enough to track certain aspects of someone’s health in real time, and without the comparatively vast bulk of existing blood glucose and cardiac monitors, just to cite one example.

This isn’t the first time we’ve seen such tiny microbatteries developed. Back in 2013, researchers 3D-printed a battery that’s just 1mm wide, and in 2014, we saw a graphene-based microbattery that could also power implants. But it’s arguably the most sophisticated and realistic design yet. On the slightly larger front, last month a team of Stanford researchers developed an aluminum graphite battery that could charge up a smartphone in just 60 seconds. But in the end, it may be no surprise that holograms help us engineer better batteries — after all, we could be living inside a hologram all this time.