Enhanced Photoassisted Li‐O₂ Battery with Ce‐UiO‐66 Metal‐Organic Framework Based Photocathodes

Abstract

Li‐O2 batteries have attracted extensive attention because of their theoretical specific energy equivalent to gasoline, but the poor electrical conductivity of Li2O2 leads to high overpotential, which limits their further development and application. Herein, this work introduces Ce‐UiO‐66, a metal‐organic framework material, as the photocatalyst to reduce the overpotential in the discharging and charging processes. With the simple in situ growth of Ce‐UiO‐66 on carbon cloth as an integrated photocathode, the photoassisted Li‐O2 batteries display decent discharge and charge voltages of 3.1 and 3.6 V, and a lifespan of 160 cycles. Moreover, theoretical calculations have been carried out to understand the band structure, spectroscopy, and photocatalytic property of Ce‐UiO‐66. The findings will encourage an enormous variety of novel MOFs‐based photocathodes for solar energy utilization systems.

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

“…When compared with representative, outstanding photo-assisted Li-O 2 batteries in Figure 4e, the Fe-UiO-66 photocathode outperforms by sustaining 500 cycles with higher round-trip efficiency and lower charge/discharge polarization voltage (0.14 V). [7,[13][14]18,36] In comparison to our previously reported Ce-UiO-66 photocathodes, the Fe-UiO-66 photocathodes demonstrated marked enhancement in electrochemical performance, especially for the cycle stability (Figure S22, Supporting Information).…”

“…[17] Our previous work demonstrated that Li-O 2 batteries with Ce-UiO-66 photocathodes exhibit impressive electrochemical performance under illumination. [18] Ce-UiO-66 extends its light absorption to the visible region due to Ce's low-lying empty 4f orbitals. Notably, targeted single-site MOF node modification is a versatile method for creating stable and active catalysts, capitalizing on noble and transition metals.…”