Biaxially Compressive Strain in Ni/Ru Core/Shell Nanoplates Boosts Li–CO₂ Batteries

Abstract Regulating surface strain of nanomaterials is an effective strategy to manipulate the activity of catalysts, yet not well recognized in rechargeable Li–CO₂ batteries. Herein, biaxially compressive strained nickel/ruthenium core/shell hexagonal nanoplates (Ni/Ru HNPs) with lattice compression of ≈5.1% and ≈3.2% in the Ru {10−10} and (0002) facets are developed as advanced catalysts for Li–CO₂ batteries. It is demonstrated that tuning the electronic structure of Ru shell through biaxially compressive strain engineering can boost the kinetically sluggish CO₂ reduction and evolution reactions, thus achieving a high‐performance Li–CO₂ battery with low charge platform/overpotential (3.75 V/0.88 V) and ultralong cycling life (120 cycles at 200 mA g⁻¹ with a fixed capacity of 1000 mAh g⁻¹). Density functional theory calculations reveal that the biaxially compressive strain can downshift the d‐band center of surface Ru atoms and thus weaken the binding of CO₂ molecules, which is energetically beneficial for the nucleation and decomposition of Li₂CO₃ crystals during the discharge and charge processes. This study confirms that strain engineering, though constructing a well‐defined core/shell structure, is a promising strategy to improve the inherent catalytic activity of Ru‐based materials in Li–CO₂ batteries.