Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230026, Anhui, China.
Proc Natl Acad Sci U S A. 2023 Feb 7;120(6):e2217454120. doi: 10.1073/pnas.2217454120. Epub 2023 Jan 31.
Lithium-carbon dioxide (Li-CO) batteries are regarded as a promising electrochemical system owing to their energy storage capability and CO utilization. However, the reported operating voltage of ~2.6 V is increasingly questioned as seemingly beyond the capability of the electrochemical carbon dioxide reduction reaction to carbon. Herein, the real operating voltage of a Li-CO battery is reacquainted, and the operating voltage and the equilibrium potential are clarified to be ~1.1 V and ~2.82 V, respectively. The products formed at low voltage are identified to be crystalline LiCO, amorphous C, and explicitly amorphous LiCO. Moreover, by decoupling small currents, 1% O, and 500 ppm HO, the operating voltage plateaus are stimulated to ~2.0 V. An ever-increasing plateau can be achieved up to the reported level of ~2.6 V activated by a minor air leak or residue in test environments. Conclusively, the operating voltages of Li-CO batteries are proposed to be deceptive and extremely sensitive to the surrounding environments. This work unveils the real operating voltage and provides the voltage regulation rules to advance next-generation Li-CO batteries.
锂-二氧化碳（Li-CO）电池因其储能能力和二氧化碳的利用而被认为是一种很有前途的电化学系统。然而，据报道，其工作电压约为 2.6V，这似乎超出了电化学二氧化碳还原反应到碳的能力。在此，重新认识了 Li-CO 电池的实际工作电压，工作电压和平衡电位分别被澄清为约 1.1V 和 2.82V。在低电压下形成的产物被确定为结晶的 LiCO、无定形 C 和明确的无定形 LiCO。此外，通过解耦小电流、1%O 和 500ppmHO，可以将工作电压平台刺激到约 2.0V。通过在测试环境中存在微量空气泄漏或残留，可以实现高达约 2.6V 的不断增加的平台。总之，Li-CO 电池的工作电压被证明是具有欺骗性的，并且对周围环境极其敏感。这项工作揭示了实际的工作电压，并提供了电压调节规则，以推进下一代 Li-CO 电池。
