Dual‐Anion Regulation for Reversible and Energetic Aqueous Zn–CO₂ Batteries

Abstract

Aqueous Zn–CO2 batteries can not only convert CO2 into high‐value chemicals but also store/output electric energy for external use. However, their performance is limited by sluggish and complicated CO2 electroreduction at the cathode. Herein, a dual‐anion regulated Bi electrocatalyst is developed to selectively reduce CO2 to formate with a Faradaic efficiency of up to 97% at a large current density of 250 mA cm−2. With O and/or F, the rate‐determine step of CO2 electroreduction has been manipulated (from the first hydrogenation to *HCOOH desorption step) with a reduced energy barrier. Significantly, the fabricated Zn–CO2 battery exhibits a high discharge voltage of 1.2 V, optimal power density of 4.51 mW cm−2, remarkable energy density of 802 Wh kg−1, and energy‐conversion efficiency of 70.74%, stability up to 200 cycles and 68 h. This study provides possible strategies to fabricate reversible and energetic aqueous Zn–CO2 batteries by addressing cathodic problems.

Unlock flow-type reversible aqueous Zn–CO2 batteries

“…[15][16][17] Among these, aqueous Zn-CO 2 batteries have gained considerable attention due to their product diversity, room-temperature operation, low cost of Zn metal, resource abundance and benefits for industrial production. 18 Furthermore, this aqueous battery system serves as an ultimate and responsible medium for the tunable electrochemistry of CO 2 . It can regulate the generation of fuels, valuable chemicals (e.g., HCOOH, CO, C 2 H 4 and alcohols), and electricity through proton-coupled electron transfer (PCET) steps.…”

“…15–17 Among these, aqueous Zn–CO 2 batteries have gained considerable attention due to their product diversity, room-temperature operation, low cost of Zn metal, resource abundance and benefits for industrial production. 18…”