Exploring metal nanoclusters for lithium-oxygen batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Developing efficient electrocatalysts is crucial for advancing nonaqueous lithium-oxygen (Li-O2) batteries.
• Manganese dioxide (α-MnO2) nanowires are promising cathode materials but require performance enhancement.

Purpose of the Study:

• To investigate the efficacy of α-MnO2 nanowires modified with poly(3,4-ethylenedioxythiophene)-protected gold (Au) and silver (Ag) nanoclusters as hybrid oxygen electrocatalysts.
• To evaluate the performance of these novel hybrid catalysts in nonaqueous Li-O2 batteries.

Main Methods:

• Synthesis of α-MnO2 nanowires modified with Au and Ag nanoclusters (Au-MnO2 and Ag-MnO2).
• Fabrication and testing of full Li-O2 cells using pristine α-MnO2, Au-MnO2, and Ag-MnO2 as cathode catalysts.
• Analysis of electrochemical performance including overpotentials, discharge/charge capacities, and cycling stability.

Main Results:

• Au-MnO2 and Ag-MnO2 hybrid catalysts significantly outperformed pristine α-MnO2 nanowires.
• Cells with Au-MnO2 exhibited reduced discharge/charge overpotentials (0.23/1.02 V at 100 mA g⁻¹).
• Au-MnO2 enabled high capacities (5784/5020 mAh g⁻¹) and over 60 cycles at 1000 mAh g⁻¹ depth of discharge.

Conclusions:

• Au/Ag nanoclusters effectively promote oxygen electrocatalysis on α-MnO2, leading to improved Li-O2 battery performance.
• The formation of more reactive discharge product morphologies is attributed to the nanocluster modification.
• Exploring Au and Ag nanoclusters in other catalyst systems for nonaqueous oxygen electrocatalysis is recommended.