This is how used masks are converted into batteries comparable to lithium batteries

The coronavirus crisis may become the great ally of the energy storage crisis, or so a group of scientists have discovered after taking advantage of used masks in new batteries.

As important as face masks are in our current pandemic-ridden world, they have a huge impact on the environment. Now scientists have demonstrated a novel method of disposing of old masks: using them to make low-cost batteries.

Masks have proven to be the most useful defense in the war against SARS-CoV-2, but unfortunately they have a very high environmental cost, since they all have to be thrown away after a while of use, because they do not they can reuse.

A 2020 study estimates that up to 129 billion masks were used per month during the early phases of the pandemic. These end up in landfills and oceans, or are burned, giving off toxic gases.

To alleviate this environmental pressure, scientists are finding ways to recycle masks into useful things like asphalt for roads. And on that line a new study has discovered that with proper treatment, batteries can be made.

First of all, the researchers disinfected the masks with ultrasound and then immersed them in an ink made from graphene. The masks are then compressed and heated to 140°C, forming conductive balls that work like electrodes in a battery.

These are separated with an insulating layer also made from old masks, then all soaked in an electrolyte, and finally covered with a protective shell made from another type of medical waste: medication blister packs.

Mask cleaning is only part of the equation, and it wouldn’t do much good if the batteries weren’t good. But they are surprisingly effective, since the team claims to have achieved an energy density of 99.7 watt-hours per kilogram (Wh/kg).

This is close to the energy density of lithium-ion batteries, ranging from 100 to 265 Wh/kg. The researchers further improved the battery by adding nanoparticles of a calcium cobalt oxide perovskite to the electrodes.

The energy density thus more than doubled to a respectable figure of 208 Wh/kg. The most efficient version of the battery retained 82% of its capacity after 1,500 cycles and was able to supply power for more than 10 hours at a voltage of up to 0.54 V.

The team claims that these batteries have other advantages as well. The use of waste products means that they are low cost, and can be made thin and flexible, and even disposable if necessary.