High performance calcium ion battery
calcium ion battery, photovoltaics, energy, technology, 2022
Researchers from Rensselaer Polytechnic Institute in the United States have developed a special class of materials for calcium ions. Providing ways to easily insert them into the battery electrodes.
Against a backdrop of rising prices and predicted shortages of lithium-ion battery materials, the search for cheap, abundant, safe and sustainable battery chemistries has never been more critical. Calcium has been considered in batteries. But the larger size and higher charge density of its ions, relative to lithium, have posed challenges for their introduction into electrode materials.
Now, researchers from Rensselaer Polytechnic Institute in the United States have reported progress in addressing this issue and unlocking the potential of high-performance calcium ion batteries.
"The calcium ion is divalent. And therefore an ion insertion will yield two electrons per ion during battery operation," said Nikhil Koratkar, the John A. Clark and Edward T. Crossan Professor of Engineering at Rensselaer. "This enables a high-performance calcium ion battery with reduced mass and volume."
However, the larger size and higher charge density of calcium ions relative to lithium impairs diffusion kinetics and cycling stability, he added. The team has overcome this problem by developing oxide structures that contain large open spaces (heptagonal and hexagonal channels). In their work, a calcium ion battery using orthorhombic and trigonal molybdenum vanadium oxide (MoVO) polymorphs to host calcium ions is presented.
The results of the research
The researchers demonstrated that calcium ions can be rapidly moved in and out of the material. With these pathways acting as 'conduits' for reversible and rapid ion transport. The findings show that MoVO provides one of the best performances reported to date for calcium ion storage.
Specifically, for MoVO, a specific capacity of ∼203 mAh g -1 was obtained at 0,2 C, and at a 100-fold faster rate of 20 C, a capacity of ∼60 mAh g -1 was achieved. Trigonal and orthorhombic polymorphs also promoted cyclic stability and reversibility. These findings were recently published in the Proceedings of the National Academy of Sciences (PNAS).
"Calcium-ion batteries may one day, in the not-too-distant future, replace lithium-ion technology as the battery chemistry that powers our society," says Koratkar. "This work may lead to a new category batteries high-performance calcium-based solutions that use earth-abundant and safe materials and are therefore affordable and sustainable. Such batteries could find widespread use in portable and consumer electronics, electric vehicles, as well as grid and grid storage. renewable energy sources».
