Superassembly of Porous Fe_tet(NiFe)_octO Frameworks with Stable Octahedron and Multistage Structure for Superior Lithium–Oxygen Batteries

Abstract

Abstract Promising lithium–oxygen batteries (LOBs) with extra‐high capacities have attracted increasing attention for use in future electric devices. However, the challenges facing this complicated battery system still limit their practical applications. These challenges mainly consist of inefficient product evolution and low‐activity catalysts. In present work, a cation occupying, modified 3D‐architecture NiFeO cubic spinel is constructed via superassembly strategy to achieve a high rate, stable electrocatalyst for LOBs. The octahedron predominant spinel provides a stable polycrystal structure and optimized electronic structure, which dominates the discharge/charge products evolution with multiformation kinetics of crystal Li 2 O 2 and Li 2− x O 2 at low and high rate conditions and energetically favors the mass transport between the electrode/electrolyte interface. Simultaneously, the porous NiFeO framework provides adequate spaces for Li 2 O 2 accommodation and complex channels for sufficient electrolyte, oxygen, and ion transportation, which dramatically alter the cathode catalysis for an unprecedented performance. As a consequence, a large specific capacity of 23413 mAh g −1 and an excellent cyclability of 193 cycles at a high current of 1000 mA g −1 , and 300 cycles at a current of 500 mA g −1 , are achieved. The present work provides intrinsic insights into designing high‐performance metal oxide electrocatalysts for Li–O 2 batteries with fine‐tuned electronic and frame structure.