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New sodium oxide paves the way for advanced sodium-ion batteries

wallpapers News 2021-01-22
Skoltech researchers and their collaborators from France, the United States, Switzerland and Australia were able to create and describe a mixed oxide Na (Li1/3Mn2/3) O2, which is expected to be used as a cathode material for sodium-ion batteries. The lithium-ion battery can be refilled or even replaced every day.
Lithium-ion batteries are powering modern consumer equipment and driving a revolution in the field of electric transportation. But because lithium is very scarce and challenging from an environmental perspective, researchers and engineers are always looking for more sustainable and cost-effective alternatives.
One option is sodium-ion technology because sodium is much more abundant than lithium. However, Na-ion batteries are still difficult to provide high energy density and cycle stability. Therefore, laboratories all over the world are seeking the best design method for Na-based cathodes.
Skoltech professor and director of Energy Science and Technology Center Artem Abakumov and doctoral student Anatolii Morozov are members of the international team researching Renault's patented Na(Li1/3Mn2/3) O2 compound. The compound is expected to be a cathode material with high energy density, without voltage decay during multiple charging cycles, and with moisture stability.
"We have performed all transmission electron microscopy (TEM) studies using equipment on Skoltech's Advanced Imaging Core Facility. We have studied the crystal structure of Na(Li1/3Mn2/3)O2 through electron diffraction and scanned the transmission through atomic resolution Electron microscopy technology directly visualizes it. In addition, we have studied this material under various charge states through TEM, which allows us to track the evolution of its crystal structure during electrochemical cycling." Morozov said.
The research team found that the reversible specific discharge capacity of the new compound is 190 mAh/g, which is a relatively high value for cathode materials for sodium-ion batteries. Morozov also shows good capacity retention and humidity resistance, which is unusual for such compounds. "In addition, no significant voltage decay was observed during long-term cycles of Na(Li1/3Mn2/3)O2; this is the main disadvantage of similar lithium-rich layered cathode materials." Skoltech PhD student said.
However, despite these promising properties, Na(Li 1/3 Mn 2/3) O 2 still shows a large voltage hysteresis during charging and discharging, leading to a reduction in the energy efficiency of cathode materials may become a commercial implementation Obstacles. "We assume that the large voltage hysteresis is related to the migration of Mn within the structure. Therefore, in the future, it is necessary to develop a cation order model and find a way to control it to overcome this problem." Anatolii Morozov pointed out.
"The team used the Titan Themis Z electron microscope in our Advanced Imaging Core Facility (AICF), which can visualize individual atoms in a material's lattice and study its structure and its relationship with the properties of the material. However, top-of-the-line equipment is necessary, but not enough to achieve impressive scientific results. We believe that the skills of staff scientists and students are essential and have invested a lot of money in the development of these skills. With Professor Abakumov becoming AICF The close scientific collaboration between our team and Skoltech scientists is possible. This gives Skoltech a competitive advantage in implementing complex research projects or developing unique technologies.” said Yaroslava Shakhova, head of Skoltech’s advanced imaging core facilities.