Purdue University engineers use microwave plastics to increase the life of lithium-sulfur batteries

Engineers at Purdue University (West Lafayette, Indiana, USA) have discovered a way to reduce the amount of plastic in landfills while improving batteries. The method includes placing an ink-free plastic immersed in a sulfur-containing solvent in a microwave oven and then charging the battery as a carbon holder.

Lithium-sulfur batteries are known as the next-generation batteries to replace the current lithium-ion battery varieties. According to a press release issued by Purdue, lithium-sulfur batteries are cheaper and more energy-intensive than lithium-ion batteries, which is an important feature of lithium-ion batteries from electric vehicles to laptops.

The disadvantages of lithium-sulfur batteries have not lasted for too long, and can be used for about 100 charge cycles.

Researchers at Purdue University are partnered by Naval Enterprise Partners in collaboration with National University's University of Excellence and Purdue University's Energy Research Institute to increase lifespan through a process that can easily recycle plastics. According to a recent paper published in the ACS Applied Materials and Interfaces Division, placing sulfur-soaked plastics in a microwave oven converts the material into an ideal material, extending the life of the battery to 200 charge and discharge cycles.

Vilaspol, an associate professor at Purdue University's School of Chemical Engineering, said: "No matter how many times you recycle plastic, plastics are left on the earth." "We have been trying to get rid of it for a long time, which is at least one value added. Ways.

“Because lithium-sulfur batteries are becoming more popular, we want to have a longer life,” Bohr added.

Low-density polyethylene (LDPE) helps solve the long-standing problem of lithium-sulfur batteries - a phenomenon known as the polysulfide shut-off effect that limits the duration of time between charges. When a current is applied to a lithium-sulfur battery, lithium ions migrate to sulfur and undergo a chemical reaction to produce lithium sulfide. The by-product polysulfide of this reaction tends to return to the lithium side, preventing lithium ions from migrating into the sulfur. This will reduce the battery's charging capacity and its useful life.

"The easiest way to block poly sulfides is to place a physical barrier between lithium and sulfur," said Patrick King, assistant researcher in chemical engineering research at Purdue University.

Purdue pointed out that previous studies have attempted to make such barriers with biomass, such as banana peels and pistachio shells, because pores in biomass-derived carbon have the potential to capture poly sulfides. “Every material has its own benefits, but the biomass is well preserved and can be used for other purposes,” Bohr said.

Instead, the researchers thought of how to incorporate plastic into the carbon scaffold to inhibit polysulfide shuttles in the cell. Past studies have shown that LDPE combines with sulfonated groups to produce carbon.

The researchers immersed a plastic bag in a sulfur-containing solvent and placed it in a microwave oven to provide a rapid increase in the temperature required to convert to low-density polyethylene. Heat promotes sulfonation and carbonization of the plastic and causes a higher density of pores that capture polysulfide. The LDPE plastic can then be made into a carbon scaffold to separate the lithium and sulfur of the better button cell.

"Plastic-derived carbon from this process includes negatively charged sulfonate groups, which are also possessed by poly sulfides," Kim said. Sulfonated LDPE is made into a carbon scaffold, thus inhibiting polysulfide by having a similar chemical structure.

"This is the first step to increase battery capacity retention," Pol said. “The next step is to use this concept to make larger batteries.”

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