Scientists find the main factors affecting the chemical and dynamic performance of lithium-sulfur batteries

The reporter learned from the University of Science and Technology of China that the team of academician Qian Yitai and the group of professor Wang Gongming studied the kinetic behavior of metal cobalt-based compounds in lithium-sulfur chemistry through a combination of experiments and theory The position of the anionic valence electron p-band center relative to the Fermi level is the main factor that affects the kinetic properties of the electron transfer reaction at the interface of lithium-sulfur batteries. The research results were published in the "Joule" magazine, a top international energy materials journal.

Lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical specific capacity, energy density, and low cost. However, the dissolution of lithium polysulfide, an intermediate product in the charging and discharging process, caused a shuttle effect, which severely limited its practical application.

Through research on the conversion kinetics, researchers have discovered that the prepared metal cobalt-based compounds exhibit completely different electrochemical kinetic behaviors.

DFT simulation results and simultaneous charge differential density analysis show that by attempting to correlate the p-band center position of the anion valence bands of different cobalt-based compounds with the kinetic properties of the electrochemical conversion of polysulfide compounds, it was found that the p-band center of the anion valence electron was changed The position relative to the Fermi level can effectively regulate the kinetics of the interface electron transfer reaction, thus becoming the main factor affecting the Li-S chemical kinetics. This achievement will play a guiding role in Li-S battery application research and development. (Reporter Wu Changfeng)

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