Studying Epoxy Composites from Battery Waste
A team of researchers from Spain recently studied the use of microparticles recovered from worn-out batteries as fillers for epoxy resins in an effort to recycle the material. According to the study, zinc alkaline batteries are one of the most popular sources of portable electrical energy, with more than 300,000 tons being consumed every year.
The study was recently published in the journal Materials by authors Isaac Lorero, Mónica Campo, Carmen Arribas, Margarita Gonzalez Prolongo, Felix Antonio López and Silvia G. Prolongo.
Battery Microparticle Research
The research team notes that recycling batteries is an important challenge today, adding that it was first identified by the European Commission on the Strategic Action Plan on Batteries: Building a Strategic Battery Value in Europe, in April 2019. In finding more effective recycling processes, recycled products should be used for the production of new batters or other applications.
An alkaline battery reportedly includes several valuable ingredients, including zinc oxide (ZnO), which can be used in many applications, such as electronics, solar cells, photocatalysis and sensors. However, according to the study, since ZnO particles are expensive to make, the recycling of these microparticles from waste can provide a sustainable and long-term solution.
Adding nanocomposites to coatings can be used for protective coatings or pigments, with structural composites for high thermal stability. Additionally, ceramic nanofillers can enhance thermal and mechanical properties, hardness and hydrophobicity of epoxy resins.
Using an epoxy thermosetting resin from Huntsman International LLC. (Houston), which was based on diglycidyl ether of bisphenol A and cured at 140 C (284 F) for 8 hours, the researchers created samples by pouring the epoxy into a two millimeter (0.08 inch) mold and cut into different specimens. Alongside the recycled ZnO battery microparticles, two other commercial ceramic oxide nanoparticles were tested: ZnO and TiO2.
Using Field Emission Gun Scanning Electron Microscopy (FEG-SEM) and Fourier Transform Infrared Spectroscopy (FTIR), the scientists looked at potential benefits of recycled ZnO as an epoxy resin filled compared to its commercial counterparts.
Researchers found that each of these microparticles have a different morphology and size. The geometry of the recycled ZnO was described by the team as similar to “desert roses,” which each petal acted as a nanosheet, whereas commercial ZnO rectangular parallelepipeds nanoparticles and commercial TiO2 are smaller spherical nanoparticles.
After testing, it was shown that the addition of ceramic fillers did not impact the thermoset’s thermal strength and mechanical stiffness. The recycled ZnO composite also had the same hydrothermal resilience as the original epoxy thermoset.
However, because of its roughness due to its flowerlike microparticles, the addition of the recycled battery filler exhibited hydrophilic properties. The water angle contact increased about 12% with the presence of ceramic particles, but the epoxy resin reinforced with the recycled ZnO microparticles exhibited the highest hydrophobicity at 35%.
When etched with acid stearic and acetic acid corrosion of the ZnO on the surface was induced, also enhancing the growth of the surface roughness. The presence of desert rose ZnO particles also enhances the lotus effect.