By Michael Irving
January 30, 2022
Facebook
Twitter
Flipboard
LinkedIn
Discarded face masks could soon be recycled into batteries
Photo credit: Depositphotos
VIEW 1 IMAGES
Personal protection equipment (PPE) is one of our most
crucial defenses in the war against SARS-CoV-2, but unfortunately it needs to
be disposable to provide maximum protection. That of course adds up to a huge
burden of waste, with a 2020
study estimating that up to 129 billion face masks were used each
month during the early stages of the pandemic. These end up in landfill, oceans
and other environments, or are burned, giving off toxic gases.
To relieve this pressure, scientists are finding ways to
recycle masks into useful things, such as road
materials. And in that vein, a new study has now found that with the right
treatment, they actually make fairly decent batteries.
First, the researchers disinfected the masks using
ultrasound, then dipped them into an ink made of graphene. Next, the masks are
compressed and heated to 140 °C (284 °F), forming conductive “pellets” that
work as the electrodes of a battery. These are separated by an insulating layer
that’s also made of old masks, then the whole thing is soaked in an electrolyte
and finally covered in a protective shell that’s made of a different type of
medical waste – drug blister packs.
Of course, cleaning up face masks is only part of the equation,
and it wouldn’t be much help if the batteries weren’t any good. But they’re
surprisingly effective, with the team claiming that they achieved an energy
density of 99.7 watt-hours per kilogram (Wh/kg). That’s approaching the energy
density of the ubiquitous lithium-ion battery, which ranges between 100 and 265
Wh/kg.
The researchers improved the battery even further by adding
nanoparticles of a calcium-cobalt oxide perovskite to the electrodes. This more
than doubled the energy density, bringing it up to a respectable 208 Wh/kg. The
best-performing version of the battery retained 82 percent of its capacity
after 1,500 cycles, and could deliver energy for more than 10 hours at a
voltage up to 0.54 V.
The team says that these batteries have a number of other
benefits too. Using waste products means they’re low-cost, and they can be made
thin and flexible, and even disposable if need be (although that might undercut
the original intention somewhat).
The research was published in the Journal of Energy Storage.
Source: National
University of Science and Technology