High-Entropy Conversion-Alloying Anode Material for Advanced Potassium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Potassium-ion batteries (KIBs) are promising for energy storage.
• Anode materials face challenges like large lattice strain and sluggish kinetics.
• Conversion-alloying dual-mechanism materials offer high theoretical capacity but require optimization.

Purpose of the Study:

• To develop an advanced anode material for KIBs using a high-entropy strategy.
• To investigate the electrochemical performance and mechanism of a novel high-entropy telluride (HET).
• To enhance the rate and cyclability of KIB anodes.

Main Methods:

• Synthesis and characterization of high-entropy telluride (Sb$_{1.4}$Bi$_{0.2}$Sn$_{0.2}$Co$_{0.1}$Mn$_{0.1}$Te$_{3}$) as an anode material.
• Electrochemical testing including rate capability and cycling stability measurements.
• Analysis of the K-ion storage mechanism and solid electrolyte interphase (SEI) formation.

Main Results:

• The HET material exhibits a disordered coordination environment, enhancing K-ion adsorption and migration.
• The HET anode operates via a conversion-alloying dual-reaction mechanism with suppressed volume variation.
• Achieved high initial specific capacity (376.5 mAh·g^-1 at 50 mA·g^-1), excellent rate performance (175.7 mAh·g^-1 at 2000 mA·g^-1), and cycling stability over 500 cycles.
• A robust KF-rich SEI film was formed on the HET surface.
• A high-energy-density (428.8 Wh·kg^-1) K-ion full battery was assembled.

Conclusions:

• The high-entropy strategy effectively improves the electrochemical dynamics and stability of telluride-based anodes for KIBs.
• HET is a promising anode material for high-performance potassium-ion batteries.
• This work provides a new avenue for designing advanced anode materials for KIBs.