Abstract：
Lithium-carbon dioxide (Li-CO2 ) battery technology presents a promising opportunity for carbon capture and energy storage. Despite tremendous efforts in Li-CO2 batteries, the complex electrode/electrolyte/CO2 triple-phase interfacial processes remain poorly understood, in particular at the nanoscale. Here, using in situ atomic force microscopy and laser confocal microscopy-differential interference contrast microscopy, we directly observed the CO2 conversion processes in Li-CO2 batteries at the nanoscale, and further revealed a laser-tuned reaction pathway based on the real-time observations. During discharge, a bi-component composite, Li2 CO3 /C, deposits as micron-sized clusters through a 3D progressive growth model, followed by a 3D decomposition pathway during the subsequent recharge. When the cell operates under laser (λ=405 nm) irradiation, densely packed Li2 CO3 /C flakes deposit rapidly during discharge. Upon the recharge, they predominantly decompose at the interfaces of the flake and electrode, detaching themselves from the electrode and causing irreversible capacity degradation. In situ Raman shows that the laser promotes the formation of poorly soluble intermediates, Li2 C2 O4 , which in turn affects growth/decomposition pathways of Li2 CO3 /C and the cell performance. Our findings provide mechanistic insights into interfacial evolution in Li-CO2 batteries and the laser-tuned CO2 conversion reactions, which can inspire strategies of monitoring and controlling the multistep and multiphase interfacial reactions in advanced electrochemical devices.
摘要：
锂-二氧化碳（Li-CO2）电池技术为碳捕获和能量存储提供了有希望的机会。尽管在Li-CO2电池方面付出了巨大努力，复杂的电极/电解质/CO2三相界面过程仍然知之甚少，特别是在纳米级。这里,使用原位原子力显微镜和激光共聚焦显微镜-微分干涉对比显微镜，我们在纳米尺度上直接观察了Li-CO2电池中的CO2转化过程，并根据实时观察进一步揭示了激光调谐反应途径。放电期间,双组分复合材料，Li2CO3/C,通过3D渐进生长模型沉积为微米大小的簇，在随后的再充电过程中，然后是3D分解路径。当细胞在激光（λ=405nm）照射下工作时，密集堆积的Li2CO3/C薄片在放电过程中迅速沉积。充电后，它们主要在薄片和电极的界面处分解，将自身从电极分离并导致不可逆的容量退化。原位拉曼表明，激光促进了难溶性中间体的形成，Li2C2O4,进而影响Li2CO3/C的生长/分解途径和电池性能。我们的发现为Li-CO2电池中的界面演化和激光调谐的CO2转化反应提供了机械见解。这可以激发在先进的电化学装置中监测和控制多步和多相界面反应的策略。
