Unlocking Entropy-Stabilized Multinary Metal-Phosphide for High-Performance Sodium Storage Anode Material

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Alloy materials are promising for sodium-ion batteries (SIBs) due to high capacity.
• Significant volumetric variation during cycling is a major challenge for alloy anodes.
• High-entropy materials (HEMs) offer a strategy to mitigate volume expansion.

Purpose of the Study:

• To design and synthesize a novel multinary metallic phosphide anode material for SIBs.
• To leverage high-entropy concepts and carbon nanotube incorporation to improve electrochemical performance.
• To address the critical challenge of volumetric expansion in alloy anodes for SIBs.

Main Methods:

• High-energy ball milling was employed to synthesize the SnSbCuBiP4-CNT material.
• Carbon nanotubes (CNTs) were incorporated to enhance sodium-ion transport and structural stability.
• Electrochemical performance was evaluated as an anode material in SIBs and in a full cell configuration.

Main Results:

• The SnSbCuBiP4-CNT anode exhibited a low sodiation potential (≈0.4 V) and high capacity (904.1 mAh g⁻¹).
• Excellent rate capability was demonstrated, retaining 642.1 mAh g⁻¹ at 10 A g⁻¹.
• A full cell with Na2VTi(PO4)3 cathode achieved high energy (189.3 Wh kg⁻¹) and power (7322 W kg⁻¹) densities.

Conclusions:

• SnSbCuBiP4-CNT is a high-entropy anode material with outstanding electrochemical performance for SIBs.
• The material effectively mitigates volume expansion, enhancing cycling stability and capacity.
• This work presents a promising pathway for developing advanced multinary phosphide anodes for next-generation energy storage.