A Rechargeable "Rocking Chair" Type Zn-CO 2 Battery.

Rising global temperatures and critical energy shortages have spurred researches into CO ₂ fixation and conversion within the realm of energy storage such as Zn-CO ₂ batteries. However, traditional Zn-CO ₂ batteries employ double-compartment electrolytic cells with separate carriers for catholytes and anolytes, diverging from the "rocking chair" battery mechanism. The specific energy of these conventional batteries is constrained by the solubility of discharge reactants/products in the electrolyte. Additionally, H ₂ O molecules tend to trigger parasitic reactions at the electrolyte/electrode interfaces, undermining the long-term stability of Zn anodes. In this report, we introduce an innovative "rocking chair" type Zn-CO ₂ battery that utilizes a weak-acidic zinc trifluoromethanesulfonate aqueous electrolyte compatible with both cathode and anode. This design minimizes side reactions on the Zn surface and leverages the high catalytic activity of the cathode material, allowing the battery to achieve a substantial discharge capacity of 6734 mAh g ^-1 and maintain performance over 65 cycles. Moreover, the successful production of pouch cells demonstrates the practical applicability of Zn-CO ₂ batteries. Electrode characterizations confirm superior electrochemical reversibility, facilitated by solid discharge products of ZnCO ₃ and C. This work advances a "rocking chair" Zn-CO ₂ battery with an enhanced specific energy and a reversible pathway, providing a foundation for developing high-performance metal-CO ₂ batteries.
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