Study: As important as face masks are in our current pandemic-battling world, they have a huge impact on the environment. Now scientists have demonstrated a new method for disposing of old masks – using them to make low-cost, flexible, and efficient batteries.
Personal Protective Equipment (PPE) is one of our most important defenses against SARS-CoV-2, but unfortunately, it needs to be disposable to provide maximum protection. This certainly adds to a huge burden of waste, with a 2020 study estimating that 129 billion face masks were used every month during the early stages of the pandemic. These end up in landfills, oceans, and other environments, or are burned, releasing toxic gases.
To relieve this pressure, scientists are looking for ways to recycle masks and turn them 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 for quite a good battery.
First, the researchers disinfected the masks using ultrasound, then dipped them in an ink made from graphene. Next, the mask is compressed and heated to 140 °C (284 °F), forming conductive “pellets” that serve as the battery’s electrodes. These are separated by an insulating layer that is also made from the old mask, then the whole thing is soaked in an electrolyte and finally covered in a protective shell which is different from a different type of medical waste – drug blister pack gets made.
Of course, cleaning the face mask is only part of the equation, and it wouldn’t be of much help if the battery wasn’t good. But they are surprisingly effective, with the team claiming they have achieved an energy density of 99.7 watt-hours per kilogram (Wh/kg). This is approaching the energy density of the ubiquitous lithium-ion battery, which is between 100 and 265 Wh/kg.
The researchers improved the battery even further by adding nanoparticles of calcium-cobalt oxide perovskite to the electrodes. This more than doubled the energy density, bringing it to a respectable 208 Wh/kg. The best-performing version of the battery retains 82 percent of its capacity after 1,500 cycles and can provide energy for more than 10 hours at voltages up to 0.54 V.
The team says that there are many other benefits of these batteries. Using waste products means they are low cost, can be made thin and flexible, and can also be made disposable when needed.
Source: NewAtlas
