Intermetallic-driven highly reversible electrocatalysis in Li–CO2 battery over nanoporous Ni3Al/Ni heterostructure

Li–CO₂ batteries, which integrate CO₂ utilization and electrochemical energy storage, offer the prospect of utilizing a greenhouse gas and providing an alternative to the well-established lithium-ion batteries. However, they still suffer from rather limited reversibility, low energy efficiency, and sluggish CO₂ redox reaction kinetics. To address these key issues, a nanoporous Ni₃Al intermetallic/Ni heterojunction (NP–Ni₃Al/Ni) is purposely engineered here via an alloying–etching protocol, whereby the unique interactions between Al and Ni in Ni₃Al endow NP-Ni₃Al/Ni with optimum reactant/product adsorption and thus unique catalytic performance for the CO₂ redox reaction. Furthermore, the nanoporous spongy structure benefits mass transport as well as discharge product storage and enables a rich multiphase reaction interface. In situ Raman studies and theoretical simulations reveal that both CO₂ reduction and the co-decomposition of Li₂CO₃ and C are distinctly promoted by NP-Ni₃Al/Ni, thereby greatly improving catalytic activity and stability. NP-Ni₃Al/Ni offers promising application potential in Li–CO₂ batteries, with its scalable fabrication, low production cost, and superior catalytic performance.