Fluorine induced surface reconstruction of perovskite ferrite oxide as cathode catalyst for prolong-life Li-O2 battery

The LaF 3 /LFCO composite was obtained through fluorine induced surface reconstruction and exhibited excellent battery performance, including higher specific capacity and overpotential, especially prolong-life. • LaF 3 /LFCO composite was constructed through a surface reconstruction strategy. • LaF 3 /LFCO exhibits a modified electronic state that regulates Li 2 O 2 morphology. • F doped Li 2 O 2 with better conductivity was formed during the discharge process. • LaF 3 /LFCO composite as cathode catalyst can effectively prolong battery life. Lithium-oxygen batteries are widely studied because of the highest theoretical specific energy density among candidates for next-generation energy storage devices. However, the insulated bulk Li 2 O 2 generated during discharge restricts their further development. Here, we demonstrate a surface reconstruction strategy on perovskite La 0.8 Fe 0.9 Co 0.1 O 3-δ (LFCO) to construct a LaF 3 /LFCO composite, which induces a modified surface and also manipulates the electronic structure. The optimized surface and electronic structure adjust the discharge reaction pathway and form thin petal-like F doped Li 2 O 2 , which have better conductivity compared to traditional discharge product and benefit for Li-O 2 battery performance. This LaF 3 /LFCO leads to much better cycle stability (157 vs 57 cycles) in comparison to the pristine LFCO. This work suggests surface reconstruction provides a new approach in the design of cathode catalyst for long-life lithium-oxygen battery.