Magnetic electrode traces ion flows to reveal battery life in real time
Scientists at the University of Buffalo experimenting with next-generation battery designs have demonstrated how magnetism might be used to bring a new level of precision to the way we monitor a battery's state of charge. The breakthrough hinges on a novel electrode design that induces shifts in a magnetic field as ions arrive and depart, which is said reveal battery life with a high degree of accuracy.
The team's advance stems from its investigations in a field known as magneto-ionics, which refers to an ability to use the transport of ions to control magnetism. The researchers see this phenomenon as a potential way to monitor the state of charge in lithium-ion batteries, which shuttle ions back and forth between a pair of electrodes as they are charged and discharged.
Using vanadium, chromium and cyanide, the scientists created a novel magneto-ionic material, which they deployed as a "molecular magnetic electrode" in a lithium-ion battery. The material changes its magnetism as lithium ions enter and leave, and by using a ferromagnetic resonance testing unit, they were able to measure those changes to reveal the battery's charge level.
According to the team, the ion-monitoring magnetic electrode exhibits a 2,000-percent increase in accuracy and more than 5,000-percent increase in response time over previous approaches. The scientists say the characteristics of the material make it ideal for use in rechargeable batteries, and offer a pathway toward real-time monitoring of a battery's charge state.
“The main goal of this project was working on the magneto-ionics, which uses ions to control the magnetism of materials," said Shenqiang Ren, who led the research. "As the lithium ions travel in or out of the material we are using, the material will change its magnetization. We can monitor the magnetism, and this enables us to indirectly monitor the lithium ions – the state of charge. We believe this is a new way to provide an accurate, fast, responsive sensing of state of charge."
The research was published in the Proceedings of the National Academy of Sciences.
Source: University of Buffalo