Exceptionally Reversible Li-/Na-Ion Storage and Ultrastable Solid-Electrolyte Interphase in Layered GeP₅ Anode

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Traditional anodes like silicon, germanium, and tin often use amorphous phases to mitigate pulverization due to volume expansion.
• Understanding the role of crystalline structures in managing large volume changes is crucial for advanced battery materials.

Purpose of the Study:

• To synthesize and compare layered and amorphous germanium phosphide (GeP5) structures.
• To evaluate their electrochemical performance in lithium-ion and sodium-ion batteries.
• To elucidate the advantages of crystalline layered materials over amorphous phases in anodes.

Main Methods:

• Synthesis of layered and amorphous germanium phosphide (GeP5) structures.
• Electrochemical performance testing (rate capability, discharge capacities, cycling stability).
• Comprehensive experimental characterizations and density functional theory (DFT) calculations.

Main Results:

• Layered, crystalline GeP5 in a hybrid structure with carbon nanotubes shows superior electron and ion transport.
• This material exhibits excellent tolerance to volume changes and provides abundant reaction sites.
• Unprecedented initial Coulombic efficiencies and ultradurable cycling performance were achieved in both Li-ion and Na-ion batteries.

Conclusions:

• Layered, crystalline GeP5 structures offer significant advantages over amorphous phases for battery anodes.
• The hybrid structure enhances electrochemical performance, stability, and cycle life.
• Findings provide insights for designing advanced layered materials for energy storage devices.