A metal free battery could be a game changer in the ecological footprint of battery powered devices. Our daily life as we know it would be not imaginable without batteries. There is no doubt about that. The remote powering of a huge variety of devices has brought comfort and convenience to mankind. It has influenced the way we communicate with smartphones and laptops, the way we organize our household with cleaning robots, and is going to change the whole mobility sector from internal combustion powered vehicles to electric cars, planes and scooters.
However, this enormous gain in convenience has its price. Batteries contain elements, metals and minerals that are often mined under tremendous negative impact on the environment. And also can be a source of global conflict. Only about 30% of the global lithium resources can actually be mined, for example. The remaining 70% are stored non-accessibly. Batteries also contain a variety of other materials, such as cobalt or lead. In total there are more than 20 different rare minerals used in state of the art battery production. Which leads to the question of ecological usefulness of battery powered vehicles. The current study results on how much CO2 per Kilowatt hour (kWh) is produced by an electric car, vary between 39 kg CO2e/kWh to 196 kg CO2e/kWh. In this example, an electric vehicle with a 40 kWh battery has the same emissions as driving a modern day diesel car that consumes five liters of diesel per 100 km between 11,800 km and 89,400 km. And that is, before the electric car has been moved for even 1 meter! In addition, lithium based batteries are dangerous, due to their flammable nature.
Can a metal free battery be a solution to ecological problems?
Scientists at Texas A&M University are currently researching the components of a different kind of battery — a metal-free, water-based battery — which has the potential to reduce the flammable nature of current batteries. Also, the number of metallic elements used in the production process can greatly be reduced. The findings of the current research of Texas A&M University have been released in the cell reports for physical science.
“This work enables the future design of metal-free aqueous batteries. By going metal-free, we can address the pressing global demand for strategic metals used in batteries, and by going aqueous, we replace the flammable volatile electrolyte with water.”Dr. Jodie Lutkenhaus, professor and Axalta Coating Systems Chair in the Artie McFerrin Department of Chemical Engineering at Texas A&M
The basic function principle behind the metal free, water based battery is a very sensitive measurement technique called electrochemical quartz crystal microbalance. This is achieved via dissipation monitoring. The Texas A&M researchers were able to determine how electrons, ions and water transfer in the electrode as it is charged and discharged.
Image credit: Texas A&M University
“With this information, we showed that enhanced electrode-water interactions lead to improved energy storage performance,” Lutkenhaus said.
The energy storage capacity that was achieved in the current state of a water based, metal free battery was lower than that of traditional Li-ion batteries. But the research still has a long way to go. And the current results have the potential to lead the way to a more sustainable and less volatile battery in the future. The potential use cases for a sustainable battery, that uses less energy and rare materials are extremely broad. Nearly every battery design that is built around lithium ions today, could be replaced with a metal free battery.
“By using completely different materials, such as we do with polymers here, we remove metals from the picture completely. My favorite aspect of this work is our ability to deeply characterize the molecular transport processes associated with this redox polymer. Only in the last few years have we been able to resolve such effects on this time and mass scale.”Dr. Jodie Lutkenhaus, professor and Axalta Coating Systems Chair in the Artie McFerrin Department of Chemical Engineering at Texas A&M
For the future, Lutkenhaus said they will need to identify a broader variety of polymers that are compatible with the current battery design.
“Once we have that, we can produce a high-performance, full-cell for practical use,” she said.
This project is supported by the U.S. Department of Energy-Basic Energy Sciences program.
Image credit: Getty images