Interlayer engineering-induced charge redistribution in Bi₂Te₃ toward efficient Zn²⁺ and NH₄ ⁺ storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Bismuth-based materials offer potential for aqueous energy storage due to layered structures.
• Existing materials are typically limited to either zinc-ion or ammonium-ion applications.
• Developing bifunctional materials for both ZIBs and AIBs is crucial for advancing energy storage.

Purpose of the Study:

• To design and synthesize a novel bifunctional energy storage material using bismuth telluride (Bi2Te3).
• To enhance the electrochemical performance of Bi2Te3 for both zinc-ion batteries (ZIBs) and ammonium-ion batteries (AIBs).
• To investigate the structural and electrochemical mechanisms enabling dual-ion storage.

Main Methods:

• Synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) coated and embedded Bi2Te3 (Bi2Te3@PEDOT).
• Theoretical calculations and experimental characterization to analyze structural and electronic properties.
• Electrochemical testing of Bi2Te3@PEDOT as an electrode material in ZIBs and AIBs.
• Ex situ analysis to elucidate ion storage mechanisms.

Main Results:

• Bi2Te3@PEDOT exhibits enhanced structural stability and significantly improved storage capacities for both Zn2+ and NH4+ ions.
• PEDOT coating and intercalation increase interlayer spacing and facilitate charge transfer, boosting performance.
• Optimized electrodes show high discharge capacities (385 mAh g-1 in ZIBs, 235 mAh g-1 in AIBs at 0.2 A g-1) and long cycle life.
• Robust performance maintained at high mass loading (10 mg cm-2) and successful demonstration in full cells.

Conclusions:

• Bi2Te3@PEDOT is a highly effective bifunctional electrode material for both ZIBs and AIBs.
• The PEDOT modification strategy successfully enhances structural integrity and electrochemical kinetics.
• This work provides a valuable reference for designing advanced bifunctional materials for aqueous energy storage systems.