Selective A-Site Exsolution and Phase Transition in Perovskite Electrode for Efficient Flexible Znic-Air Batteries

Zinc-air batteries (ZABs) are highly promising for flexible electronics due to their high energy density and cost-effective. However, their practical application is impeded by the sluggish kinetics of the oxygen evolution and oxygen reduction reactions (OER/ORR). This study presents a novel design featuring BaO nanoparticles anchored on layered perovskite PrBaMn_1.5Co_0.5O_6-δ (PBMC) nanofibers, fabricated through a plasma method. Notably, the plasma treatment induces the selective exsolution of A-site Ba onto the perovskite surface, while simultaneously driving the transformation of PBMC from a simple perovskite to a layered perovskite, resulting in a unique BaO/PBMC heterostructure. Theoretical calculations demonstrate that the construction of the BaO/PBMC heterojunction regulates interfacial electronic redistribution, thereby lowering energy barriers for both OER and ORR. Consequently, the BaO/PBMC air electrode exhibits superior peak power density and enhanced stability in flexible solid-state ZABs, compared to the pristine PBMC cathode. Selective A-site exsolution coupled with phase transition, featuring a unique alkaline-earth metal oxide/perovskite heterostructure, may offer new insights for energy conversion technologies.