Metal Oxide Interlayer for Long-Lived Lithium-Selenium Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-selenium (Li-Se) batteries offer high theoretical energy density but suffer from polyselenide dissolution and shuttle effects, leading to capacity fading.
• Improving the electrochemical performance and cycle stability of Li-Se batteries is crucial for their practical application.

Purpose of the Study:

• To develop a novel Li-Se hybrid cell incorporating alkali activated carbon and a tungsten oxide interlayer.
• To investigate the impact of the carbon material and tungsten oxide interlayer on the electrochemical performance and cycle stability of Li-Se cells.

Main Methods:

• Fabrication of a Li-Se full cell utilizing an alkali activated carbon cathode and a tungsten oxide interlayer.
• Electrochemical characterization, including capacity measurements, cycle testing, and Li-ion diffusion coefficient determination.

Main Results:

• The Li-Se hybrid cell with 70% Se loading achieved a reversible capacity of 625 mAh g_Se^-1, outperforming the pristine Se cell (505.8 mAh g_Se^-1).
• The tungsten oxide interlayer effectively suppressed polyselenide dissolution and shuttle, reducing capacity fading.
• The Li-oxide@separator/Se-alkali activated carbon cell demonstrated reversible capacities of 808 mAh g_Se^-1 initially and 510 mAh g_Se^-1 after 100 cycles.

Conclusions:

• Alkali activated carbon significantly enhances the capacity of Li-Se cells.
• The tungsten oxide interlayer acts as an effective barrier against polyselenide crossover, improving cycle stability.
• The combined use of carbon and tungsten oxide offers a promising strategy for developing high-performance and durable Li-Se batteries.