Disentangling Plasmonic and Catalytic Effects in a Practical Plasmon-Enhanced Lithium–Oxygen Battery

Abstract

Rechargeable Li–O2 batteries have high theoretical energy density (~3600 Wh kg-1) compared to the conventional Li–ion batteries. However, the recharging process is primarily disturbed by the large overpotential attributed to the sluggish OER kinetics. Very recently, photo-assisted Li–O2 batteries with semiconductor-containing cathodes have gained attention as a promising approach for enhanced energy storage. Surface plasmon resonance (SPR), the unique property of plasmonic materials (such as Au, Ag, Cu, Pd, and Al) interacting with light, has found increasing application in catalysis. Here, we demonstrate plasmonic effects in Li–O2 systems by incorporating gold nanoparticles on a practical Ketjen Black cathode with different amounts and sizes. During discharge, plasmonic Au NPs induce a Li2O2 morphology change to small particles, which are easily decomposed during recharge. Most importantly, the SPR-induced hot carriers help to form and decompose Li2O2 and suppress carboxylate side-products, decreasing recharge voltages and increasing the round-trip efficiency up to 80.2%. Meticulous analyses of the catalytic properties of the Au NPs and the SPR-induced near-field enhancement and local heat effects are here additionally shared.