Surface-Engineered Ni₂P: An Efficient Oxygen Electrocatalyst for Zinc-Air Battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Surface engineering of electrocatalysts is crucial for enhancing intrinsic activity.
• Defect generation (anion/cation vacancies) and increased surface area are key outcomes.
• Nickel phosphide (Ni2P) is a potential electrocatalyst material.

Purpose of the Study:

• To engineer the surface of Ni2P to improve bifunctional oxygen electrocatalytic activity.
• To develop a high-performance rechargeable zinc-air battery (ZAB) using the engineered catalyst.

Main Methods:

• Synthesis of N and P-dual doped carbon encapsulated Ni2P (Ni2P@NPC) using a single-source precursor.
• Surface engineering via controlled room-temperature acid treatment.
• Characterization of catalyst properties and performance in a ZAB.

Main Results:

• Acid treatment exfoliated carbon, increased P-vacancy, and boosted electrochemically active surface area.
• Engineered Ni2P@NPC showed enhanced oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity.
• The ZAB achieved a specific capacity of 770.25 mAh gZn−1 and energy density of 692 Wh kgZn−1.

Conclusions:

• Surface engineering effectively tunes Ni2P for superior bifunctional oxygen electrocatalysis.
• The engineered catalyst enables high-performance rechargeable zinc-air batteries with excellent cycling stability.
• P-vacancy creation is beneficial for forming active oxyhydroxide species for OER.