Researchers from the National University of Science and Technology (NUST MISIS), Russia have claimed to devise a technology that can convert medical waste (including face masks) into flexible, cost-effective batteries. And because they have more benefits than traditional metal-coated batteries, applications include household, industrial and more.
“To create a battery of the supercapacitor type, the following algorithm is used: first the masks are disinfected with ultrasound, then dipped in ‘ink’ made of graphene, which saturates the mask. Then the material is pressed under pressure and heated to 140°C (conventional supercapacitor batteries require very high temperatures for pyrolysis-carbonation, up to 1000-1300°C, while the new technology reduces energy consumption by a factor of 10),” said Professor Anvar Zakhidov, scientific director of the infrastructure project ‘High-Performance, Flexible, Photovoltaic Devices Based in Hybrid Perovskites’ at NUST MISiS.
“A separator (also made of mask material) with insulating properties is then placed between the two electrodes made of the new material. It is saturated with a special electrolyte, and then a protective shell is created from the material of medical blister packs (such as paracetamol),” he added.
Pellet batteries created previously using a similar technology had a capacity of 10 watt-hours/kg. The recent development has taken that to 98 watt-hours/kg, providing more energy density and electrical capacity. The addition of nanoparticles of inorganic perovskite of CaCo oxide type to the electrodes has further increased the energy capacity to 208 watt-hours/kg.
The inclusion of graphene boosts the electrical capacity from 1000 farads per gram to 1706 farads per gram, which is high compared to the best-carbonised non-graphene electrodes.
In the future, the scientific team plans to apply the new technology for producing batteries for electric cars, solar power stations and other applications.
We studied the electrochemical performance of solid state supercapacitors (SCs) made with surgical face mask (FM) waste and blister packs recycled from paracetamol packaging. The Ca3Co4O9-δ (Calcium carbonate) oxide was also deposited on the Super-capacitors electrodes to store charge by redox reactions. The Calcium carbonate microparticles had a plate-like morphology and had sizes in the range of 1–4 µm. They also presented a monoclinic phase according to the analysis by the X-ray diffraction. The electrochemical characterization of the face mask-based super-capacitors was carried out and found maximum capacitance/energy density values of 1706.2 F g−1/208.4 Wh kg−1 and 816.8 F g−1/99.7 Wh kg−1 for the super-capacitors made with and without Calcium carbonate, respectively. Thus, incorporating the Calcium carbonate into the super-capacitors improved the energy density and capacitance by ≈108%. The best device made with Calcium carbonate also presented a moderate capacitance retention of 82.1% after 1500 cycles of charge/discharge and long discharge times of at least 10 h (at a maximum output voltage of 0.54 V). Additionally, the devices were subjected to pressing conditions by putting on them weights of 0.1–0.5 Kg and their capacitance retention was only reduced by 0.7–1.5%. The analysis by XPS, Absorbance and Raman measurements pointed out that the super-capacitors made with Calcium carbonate presented extra redox species of Co2+/Co3+ and oxygen vacancies on their electrodes; therefore, they could store charge by redox reactions. Hence, the results presented here revealed that highly efficient super-capacitors are possible to make from medical waste and this could help to decrease the environmental contamination by plastic residuals.
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