Developing highly reversible Li-CO₂ batteries: from on-chip exploration to practical application

Li-CO₂ batteries (LCBs) hold significant potential for meeting the energy transition requirements and mitigating global CO₂ emissions. However, the development of efficient LCBs is still in its early stages, necessitating the search for highly effective electrocatalysts and a deeper understanding of their mechanisms. To address these challenges, we have designed a versatile on-chip electrochemical testing platform, which enables simultaneous catalyst screening and in-situ analysis of the chemical composition and morphological evolution of reaction products. Six different metal nanoparticle catalysts were evaluated and it was found that Pt-based LCBs demonstrated a low overpotential (∼0.55 V). The reaction pathways and reversible nature of the LCBs were studied using in situ electrochemical Raman spectroscopy and atomic force microscopy, and were supported by ab initio calculations. As a result of the platform studies, LCB coin cells and pouch cells were fabricated which demonstrated high capacity, stability, and an energy efficiency of up to 90%. A multimodal lab-on-a-chip platform has a wide range of applications in other systems, such as metal-air batteries, electrocatalysts, fuel cells, and photoelectrochemical systems, thereby opening up new opportunities for rapid catalyst screening, mechanism investigation, and the development of practical applications.