A high-energy long-cycling solid-state lithium–oxygen battery enabled by plasmon-enhanced solar induced reversible oxygen conversion to Li2O

Lithium–oxygen (Li–O 2 ) battery with a reversible conversion between oxygen and lithium oxide (Li 2 O) offers the highest theoretical specific energy among all lithium-battery systems. However, enabling the O 2 /Li 2 O redox reaction to be fully reversible requires high operating temperatures (> 150 °C) due to thermodynamic constraints. Here, we report a room temperature (RT) solid-state Li–O 2 battery by solar induced reversible O 2 /Li 2 O conversion reaction. The oxygen reaction and oxygen evolution at the air cathode is driven by energetic hot carriers generated from plasmonic ruthenium nanostructures. These carriers activate O 2 molecules, cleave O–O bonds, and facilitate the formation and decomposition of the Li 2 O products via plasmon-induced four-electron (O 2 /Li 2 O) conversion process on discharge and charge, thus enabling a capacity more than twice that of the batteries operating without solar irradiation. Meanwhile, the Li/solid-state interface is stabilized by a molten-salt-interlayer (MSI), which promotes an ultra-flat and electrochemically stable interface throughout cycling under solar irradiation. By combining the plasmon-enhanced cathode and MSI-stabilized Li-anode, the solid-state Li–O 2 battery exhibits exceptional cycling performance over 350 cycles with a capacity limitation of 1000 mAh g −1 at a high current density of at 10.0 A g −1 . This dual-functional battery design enables room-temperature solid-state Li–O 2 batteries, advancing the development of next-generation high-energy density lithium metal battery. • A high-energy long-cycling solid-sate Li–O 2 battery based on a reversible 4/e − conversion reaction between O 2 and Li 2 O has been obtained at RT. • Energetic hot carries generated from plasmonic hybrid Ru nanostructures catalyst on the cathode enables reversible O 2 /Li 2 O conversion under solar irradiation. • Solar-induced heat transferred to the LAGP/Li interface, stabilized by a MSI, can effectively heal Li-dendrites, thereby significantly improving the cycling stability of the battery.