High-Performance Potassium-Tellurium Batteries Stabilized by Interface Engineering

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium-tellurium (K-Te) batteries offer potential for high performance due to tellurium's conductivity.
• Fundamental understanding of K-Te reaction mechanisms and cathode design is lacking.

Purpose of the Study:

• To elucidate the reaction pathway and cathode structure in K-Te batteries.
• To enhance the stability and performance of K-Te battery systems through interface engineering.

Main Methods:

• Utilized X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction to characterize reaction products.
• Employed atomic layer deposition to apply an ultrathin aluminum oxide (Al2O3) coating on the tellurium electrode.

Main Results:

• Identified a two-step reaction pathway: Te -> K2Te3 -> K5Te3 in carbonate electrolytes.
• The Al2O3 coating facilitated a stable solid electrolyte interphase (SEI) layer, reducing active material loss.
• Achieved remarkable cycling stability with <0.01% capacity decay per cycle over 500 cycles at 1 C.

Conclusions:

• Interface engineering with Al2O3 coating stabilizes the electrode surface and enhances structural integrity.
• The strategy ensures reliable electron transfer and K-ion conduction, crucial for long-term battery operation.
• Findings pave the way for developing high-energy-density potassium-sulfur, potassium-selenium, and potassium-tellurium batteries.