Bismuth-based mixed-anion compounds for anode materials in rechargeable batteries

Area of Science:

• Materials Science
• Electrochemistry
• Inorganic Chemistry

Background:

• Developing advanced anode materials is crucial for enhancing rechargeable battery performance.
• Ternary mixed-anion compounds offer unique electrochemical properties due to tunable compositions.
• Bismuth-sulfur-iodine (Bi-S-I) systems present potential for high-capacity energy storage.

Purpose of the Study:

• To establish a facile solvothermal synthesis route for precise chemical composition control in ternary Bi-S-I systems.
• To investigate the electrochemical performance of these novel bismuth-based compounds as anode materials in rechargeable batteries.
• To correlate synthesis conditions with material properties and battery performance.

Main Methods:

• Solvothermal synthesis with controlled sulfide concentration for tunable Bi-S-I compositions.
• Material characterization using techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM).
• Electrochemical testing in lithium-ion battery configurations to evaluate capacity and cycling stability.

Main Results:

• A facile solvothermal method was developed to control the chemical composition of ternary Bi-S-I systems by adjusting sulfide concentration.
• Bismuth-based ternary mixed-anion compounds, specifically Bi₁₃S₁₈I₂ and BiSI/Bi₁₃S₁₈I₂, were synthesized and tested as anode materials.
• Cells utilizing Bi₁₃S₁₈I₂ demonstrated an initial capacity of 807 mA h g^-1, while BiSI/Bi₁₃S₁₈I₂ achieved 1087 mA h g^-1 in lithium-ion battery systems.

Conclusions:

• The solvothermal synthesis approach offers effective control over the composition of ternary Bi-S-I materials.
• These bismuth-based ternary mixed-anion compounds are promising high-capacity anode materials for rechargeable batteries.
• The demonstrated performance highlights the potential of mixed-anion strategies for next-generation energy storage solutions.