In Situ Electrochemical Study of Na-O-2/CO2 Batteries in an Environmental Transmission Electron Microscope
In Situ Electrochemical Study of Na-O-2/CO2 Batteries in an Environmental Transmission Electron Microscope
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环境透射电子显微镜下 Na-O-2/CO2 电池的原位电化学研究
DOI：
10.1021/acsnano.0c04938
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发表时间：
2020
期刊：
影响因子：
17.1
通讯作者：
Huang Jianyu
中科院分区：
文献类型：
--
作者：
Liu Qiunan;Tang Yongfu;Sun Haiming;Yang Tingting;Sun Yong;Du Congcong;Jia Peng;Ye Hongjun;Chen Jingzhao;Peng Qiuming;Shen Tongde;Zhang Liqiang;Huang Jianyu
金属-空气电池具有较高的理论能量密度，是后锂储能装置的潜在候选者。然而，我们对金属-空气电池电化学的理解仍处于起步阶段。本文报道了以碳纳米管（CNTs）或银纳米线为空气阴极介质的Na-O2 /CO2（o2和CO2混合物）和Na-O2电池在高级像差校正环境透射电子显微镜下的研究情况。在Na-O2 / CO2-CNT纳米电池中，放电反应分两步进行：(1)2Na++ 2e - + O2→Na2O2；(2) Na2O2+ CO2→Na2CO3+ O2；同时发生寄生镀钠反应。电荷反应通过(3)2Na2CO3+ C→4Na++ 3CO2+ 4e -进行。在Na-O2 / CO2-Ag纳米电池中，放电反应与Na-O2 / CO2-CNT纳米电池基本相同；然而，前者的电荷反应非常缓慢，表明na2co3的直接分解是困难的。在na - o2电池中，放电反应发生在反应1中，但逆反应非常困难，说明Na2O2分解缓慢。总的来说，Na-O2 / CO2-CNT纳米电池表现出比Na-O2 / CO2-Ag和Na-O2 - cnt纳米电池更好的可循环性和性能，强调了碳和co2在促进Na-O2纳米电池中的重要性。我们的研究提供了对Na-O2 / co2和Na-O2纳米电池电化学性质的重要理解，这可能有助于开发高性能的Na-O2 / co2和Na-O2储能电池。
Metal–air batteries are potential candidates for post-lithium energy storage devices due to their high theoretical energy densities. However, our understanding of the electrochemistry of metal–air batteries is still in its infancy. Herein we reportin situstudies of Na–O2/CO2(O2and CO2mixture) and Na–O2batteries with either carbon nanotubes (CNTs) or Ag nanowires as the air cathode medium in an advanced aberration corrected environmental transmission electron microscope. In the Na–O2/CO2–CNT nanobattery, the discharge reactions occurred in two steps: (1) 2Na++ 2e–+ O2→ Na2O2; (2) Na2O2+ CO2→ Na2CO3+ O2; concurrently a parasitic Na plating reaction took place. The charge reaction proceededvia(3) 2Na2CO3+ C → 4Na++ 3CO2+ 4e–. In the Na–O2/CO2–Ag nanobattery, the discharge reactions were essentially the same as those for the Na–O2/CO2–CNT nanobattery; however, the charge reaction in the former was very sluggish, suggesting that direct decomposition of Na2CO3is difficult. In the Na–O2battery, the discharge reaction occurredviareaction 1, but the reverse reaction was very difficult, indicating the sluggish decomposition of Na2O2. Overall the Na–O2/CO2–CNT nanobattery exhibited much better cyclability and performance than the Na–O2/CO2–Ag and the Na–O2–CNT nanobatteries, underscoring the importance of carbon and CO2in facilitating the Na–O2nanobatteries. Our study provides important understanding of the electrochemistry of the Na–O2/CO2and Na–O2nanobatteries, which may aid the development of high performance Na–O2/CO2and Na–O2batteries for energy storage applications.