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Comprehensive Summary: The increasing demand for high‐energy storage systems has propelled the development of Li‐air batteries and Li‐O2/CO2 batteries to elucidate the mechanism and extend battery life. However, the high charge voltage of Li2CO3 accelerates the decomposition of traditional sulfone and ether electrolytes, thus adopting high‐voltage electrolytes in Li‐O2/CO2 batteries is vital to achieve a stable battery system. Herein, we adopt a commercial carbonate electrolyte to prove its excellent suitability in Li‐O2/CO2 batteries. The generated superoxide can be captured by CO2 to form less aggressive intermediates, stabilizing the carbonate electrolyte without reactive oxygen species induced decomposition. In addition, this electrolyte permits the Li metal plating/stripping with a significantly improved reversibility, enabling the possibility of using ultra‐thin Li anode. Benefiting from the good rechargeability of Li2CO3, less cathode passivation, and stabilized Li anode in carbonate electrolyte, the Li‐O2/CO2 battery demonstrates a long cycling lifetime of 167 cycles at 0.1 mA·cm–2 and 0.25 mAh·cm–2. This work paves a new avenue for optimizing carbonate‐based electrolytes for Li‐O2 and Li‐O2/CO2 batteries. [ABSTRACT FROM AUTHOR]

The lithium (Li)–air battery has an ultrahigh theoretical specific energy, however, even in pure oxygen (O2), the vulnerability of conventional organic electrolytes and carbon cathodes towards reaction intermediates, especially O2−, and corrosive oxidation and crack/pulverization of Li metal anode lead to poor cycling stability of the Li‐air battery. Even worse, the water and/or CO2 in air bring parasitic reactions and safety issues. Therefore, applying such systems in open‐air environment is challenging. Herein, contrary to previous assertions, we have found that CO2 can improve the stability of both anode and electrolyte, and a high‐performance rechargeable Li–O2/CO2 battery is developed. The CO2 not only facilitates the in situ formation of a passivated protective Li2CO3 film on the Li anode, but also restrains side reactions involving electrolyte and cathode by capturing O2−. Moreover, the Pd/CNT catalyst in the cathode can extend the battery lifespan by effectively tuning the product morphology and catalyzing the decomposition of Li2CO3. The Li–O2/CO2 battery achieves a full discharge capacity of 6628 mAh g−1 and a long life of 715 cycles, which is even better than those of pure Li–O2 batteries. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The increasing demand for high‐energy storage systems has propelled the development of Li‐air batteries and Li‐O2/CO2 batteries to elucidate the mechanism and extend battery life. However, the high charge voltage of Li2CO3 accelerates the decomposition of traditional sulfone and ether electrolytes, thus adopting high‐voltage electrolytes in Li‐O2/CO2 batteries is vital to achieve a stable battery system. Herein, we adopt a commercial carbonate electrolyte to prove its excellent suitability in Li‐O2/CO2 batteries. The generated superoxide can be captured by CO2 to form less aggressive intermediates, stabilizing the carbonate electrolyte without reactive oxygen species induced decomposition. In addition, this electrolyte permits the Li metal plating/stripping with a significantly improved reversibility, enabling the possibility of using ultra‐thin Li anode. Benefiting from the good rechargeability of Li2CO3, less cathode passivation, and stabilized Li anode in carbonate electrolyte, the Li‐O2/CO2 battery demonstrates a long cycling lifetime of 167 cycles at 0.1 mA·cm–2 and 0.25 mAh·cm–2. This work paves a new avenue for optimizing carbonate‐based electrolytes for Li‐O2 and Li‐O2/CO2 batteries. [ABSTRACT FROM AUTHOR]