Impact of electrolyte solutions on carbon dioxide fixation in single chamber Al–CO2 battery

Abstract

Governments and research & development (R&D) organizations are actively initiating various programs and research strategies for CO₂ capture, its utilization, and integration with long duration energy storage from renewable sources worldwide. In line with the carbon capture goals, here we report a novel electrochemical Al-CO₂ battery cell, that can simultaneously capture CO₂ and convert it into value-added products, in addition to long-duration energy generation and storage. This innovative approach employs cost-effective Al metal as an anode and an in-house synthesized Ni–Fe based bimetallic double hydroxide catalyst as the cathode, with meticulously optimized compositions and morphologies. We explore the impact of different aqueous electrolyte solutions compositions on the cell performance, demonstrating up to 10 h of stable long duration energy storage with a stable voltage profile. The cell exhibits low polarization even at high current densities of up to 12 mA cm⁻² and maintains stable cycling over 500 h. Through Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray Diffraction and X-ray photoelectron spectroscopy (XPS) analysis, we determined that the discharge product is either NaAlCO₃(OH)₂ or KAlCO₃(OH)₂, distinct from the Al₂(CO₃)₃ typically reported in conventional Al–CO₂ batteries.