Triphase Heterogeneous Electrocatalysts of Ni and Co for High‐Performing Li‐O₂ Batteries

ABSTRACT The limited energy density of the current Li‐ion batteries restricts the electrification of transportation to small‐ and medium‐scale vehicles. On the contrary, Li‐O 2 batteries (LOBs), with their significantly higher theoretical energy density, can power heavy‐duty transportation, if the sluggish electrode kinetics in these devices can be substantially improved. The use of solid electrocatalysts at the cathode is a viable strategy to address this challenge, but current electrocatalysts fail to provide sufficient discharge depths and cyclability, primarily due to the formation of the film‐like discharge product, Li₂O₂, on catalytic sites, which obstructs charge transport and gas diffusion pathways. Here, we report that a triphase heterogeneous catalyst comprising NiCoP, NiCo 2 S 4 , and NiCo 2 O 4 , assembled into a hierarchical hollow architecture (NC‐3@Ni), efficiently modulates the morphology and orientation of the discharge product, facilitating the sheet‐like growth of Li 2 O 2 perpendicular to the cathode surface. These modifications enable the assembled LOB to deliver a high discharge capacity of 25 162 mAh g −1 at 400 mA g −1 , along with impressive cycling performance, achieving 270 cycles with a discharge depth of 1000 mAh g −1 , exceeding 1350 h of continuous operation. This promising performance is attributed to the presence of individual electrophilic and nucleophilic phases within the heterogeneous microstructure of the triphase catalyst, collectively promoting the formation of sheet‐like Li 2 O 2 . image