Pt ₁ /MnO ₂ Nanotip Inducing Local Electric Field Intensifies Oxygen Transport for High‐Energy‐Density Al‐Air Battery Stacks

Abstract

ABSTRACT Modulating the coordination environment of atomic site catalysts is a promising strategy to enhance the oxygen reduction reaction (ORR) of Al‐air battery; however, its practical development is greatly hindered by inefficient oxygen transport across the air cathode. Herein, we design a branch‐like MnO 2 support with exposed (100) facets anchoring Pt single atoms (B‐Pt 1 /MnO 2 ) to address the oxygen transport bottleneck. We demonstrate that the nanotips of branch‐like MnO 2 can induce a localized electric field that significantly enhances mesoscale oxygen transport, as validated by finite element simulation, ab initio molecular dynamics, and oxygen diffusion experiments. Meanwhile, we show that the Pt‐O 4 coordination stabilized by the (100) facet lowers the reaction energy barrier and hinders Pt leaching. This multiscale microenvironment regulation enables B‐Pt 1 /MnO 2 to achieve an ultrahigh energy density of 3690.6 Wh kg −1 and remarkable stability for over 650 h at 50 mA cm −2 , outperforming all previously reported catalysts. The ensembled practical Al‐air battery stack achieves an energy density of 480.2 Wh kg −1 , which is close to the United States Department of Energy requirements for power battery. Techno‐economic analysis reveals a system cost per kW·h only 1/50 of the reported Al‐air battery, highlighting its feasibility for sustainable energy applications.