Lewis-Acidic PtIr Multipods Enable High-Performance Li-O₂ Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Aprotic lithium-oxygen (Li-O2) batteries face challenges with sluggish oxygen reaction kinetics, high overpotentials, and parasitic reactions.
• These issues limit the efficiency and stability of Li-O2 battery cathodes.

Purpose of the Study:

• To develop an advanced cathode material for Li-O2 batteries that improves overpotentials and stability.
• To investigate the role of PtIr multipods in enhancing oxygen reaction kinetics and reducing parasitic reactions.

Main Methods:

• Synthesis of PtIr multipods as cathode material.
• Density Functional Theory (DFT) calculations to understand electronic structure and binding energies.
• Electrochemical testing of Li-O2 cells using PtIr electrodes.

Main Results:

• PtIr multipods exhibit low Lewis acidity due to electron transfer from Ir to Pt, weakening binding with LiO2 intermediates.
• Achieved significantly low oxygen-reduction-reaction (ORR) and oxygen-evolution-reaction (OER) overpotentials.
• Li-O2 cells demonstrated a low discharge/charge overpotential (0.44 V) and excellent cycle life (180 cycles).

Conclusions:

• PtIr multipods are effective cathode materials for aprotic Li-O2 batteries.
• The unique electronic properties of PtIr reduce overpotentials and enhance stability.
• This work offers a promising noble-metal-based cathode for advanced Li-O2 battery applications.