Researchers at Cornell University have developed a new application for the element indium to enhance the efficiency of lithium batteries, a fundamental component of electric vehicles.
Indium is a chemical element commonly used in touch screens, televisions, and solar panels. In a study published in Joule
on January 26, led by Shuo Jin and his team at Cornell, indium was identified as a battery component enabling rapid charging and long-term energy storage. Using the study's findings, researchers at Cornell developed a battery that can be charged in less than five minutes.
Although the development of electric vehicles is essential for reducing greenhouse gas emissions, their cost often remains prohibitive for most consumers. However, the new battery represents a step towards better accessibility of electric vehicles, according to Professor Lynden Archer, Dean of the Cornell College of Engineering. "[Electric vehicle manufacturers] have focused on building bigger batteries for greater travel range," said Lynden Archer. "[These bigger batteries] cost a lot more... the industry ends up producing specialized products that only a portion of society can afford."
Indium stands out as a unique battery component because of its unusually fast solid-state diffusivity for lithium. This solid-state diffusivity refers to the ability of a material - in this case, charged lithium atoms - to move through the solid materials of the positive electrode, where electricity flows in the battery. This flow of charged lithium atoms creates an electrical current that is then stored as energy for later use. Thanks to an indium anode allowing for quicker lithium ion diffusion, the battery charges in just a few minutes.
Furthermore, indium helps to distribute charged lithium atoms evenly, which maintains the integrity of the electrode, especially through repeated charging cycles. The more stable the electrode of a battery is, the less often the battery needs to be replaced. "[The balance between rapid diffusivity and even distribution] is the secret to designing very fast-charging batteries that last a long time," added Lynden Archer.
An indium battery can be charged and used repeatedly over hundreds of cycles while retaining its performance capacities, which is important for the sustainability of a car battery. The more a battery can be used before being repaired or replaced, the more it offsets the environmental impacts of its initial production.
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Although it enhances charging efficiency and battery life, indium is heavy. A heavier battery means a heavier car, which is much less efficient and generally requires a lot more power to travel the same distances. To address this weight concern, Lynden Archer and his team mixed indium with aluminum, a much lighter but chemically similar element. Because the two share important characteristics, mixing the two elements could solve the weight problem without compromising the beneficial properties of indium.
However, significant work remains before batteries using indium can be incorporated into cars. To fully charge a new lithium and indium battery in just five minutes, stations would need to provide electrical current approximately five to six times higher than what is currently possible.
The research team plans to continue examining the capabilities and limitations of indium and other similar elements. They hope to reduce the need for large electric vehicle batteries and make electric vehicles accessible to a broader range of consumers. By discovering other materials that could further improve car batteries, Lynden Archer hopes to contribute to lighter, easier-to-manufacture, and less expensive electric cars.