Two Better Than One: Enhanced Photo‐Assisted Li‐O₂ Batteries with Bimetallic Fe‐UiO‐66 Metal‐Organic Framework Photocathodes

Abstract Li‐O₂ batteries, known for their impressive theoretical specific energy, face significant practical challenges, including slow kinetics, voltage hysteresis, and reduced cycle life. In this study, a novel approach is introduced utilizing a bimetallic metal‐organic framework known as Fe‐UiO‐66 as a multifunctional photocatalyst to enhance the oxygen‐related reactions in photo‐assisted Li‐O₂ batteries. In contrast to UiO‐66, Fe‐UiO‐66 exhibits an extended response to visible light, as confirmed through UV–vis and photoluminescence spectra. Electron paramagnetic resonance analysis provides further validation of the pivotal role played by O₂⁻ radicals in the electrochemical processes. Additionally, computations are employed to elucidate the distinct function of Fe centers and the underlying reaction mechanisms. Li‐O₂ batteries with Fe‐UiO‐66 cathodes have a reduced charge/discharge voltage difference of 0.14 V under illumination and operate stably for 500 cycles. This work encourages MOF‐based photocathode development for Li‐O₂ batteries.