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

• Published in: eScience (Beijing) 2023-06, Vol.3 (3), p.100114, Article 100114
• Main Authors: Jian, Tianzhen, Ma, Wenqing, Xu, Caixia, Liu, Hong, Wang, John
• Format: Article
• Language: English
• Subjects: Dealloying; Li–CO2 batteries; Nanoporous; Ni3Al intermetallic
• ISSN: 2667-1417; 2667-1417
• DOI: 10.1016/j.esci.2023.100114

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. Uniformly nanoporous intersecting Ni3Al intermetallic/Ni heterojunction (NP–Ni3Al/Ni) was easily fabricated by dealloying Ni–Al alloy. The unique interactions between Al and Ni in Ni3Al, along with a 3D network backbone containing rich pore channels, endowed NP-Ni3Al/Ni with decent catalytic activity and durability for the CO2 redox reaction. In situ Raman studies and theoretical simulations revealed that both CO2 reduction and the co-decomposition of Li2CO3 and C were distinctly promoted by the engineering of intermetallic Ni3Al. Given its laudable performance and simple fabrication, NP-Ni3Al/Ni shows great promise as a cost-effectiveness candidate for the cathode catalyst in the CO2 redox reaction in Li–CO2 batteries. [Display omitted] •Heterostructured NP-Ni3Al/Ni is constructed using a tailored dealloying protocol.•Ni3Al intermetallic compound provides optimal electronic modulation for the CO2 redox reaction.•The spongy structure is preferable for achieving high battery reaction kinetics.•NP-Ni3Al/Ni distinctly promotes the reversibility of a Li–CO2 battery.•The synergy between Ni3Al and the spongy structure generates decent catalytic performance.