Effects of CO2 accumulation during cycling of a Li–O2 battery on the transition of discharge product and performance fading
Effects of CO2 accumulation during cycling of a Li–O2 battery on the transition of discharge product and performance fading
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DOI：
10.1016/j.nanoen.2019.104171
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发表时间：
2019-10
期刊：
影响因子：
17.6
通讯作者：
Libin Chen;Yu‐hao Hong;Liangping Xiao;Jinhai You;Wen-Jia Sheng;Ling Huang;H. Bai;Shigang Sun
中科院分区：
文献类型：
--
作者：
Libin Chen;Yu‐hao Hong;Liangping Xiao;Jinhai You;Wen-Jia Sheng;Ling Huang;H. Bai;Shigang Sun
充放电循环过程中充电电位的升高严重降低了锂氧电池的循环寿命，但其原因尚不完全清楚。目前的研究重点是揭示锂氧电池充电电位增加背后的内在基础，并开发抑制这种现象的策略。基于X射线衍射、傅里叶变换红外光谱、扫描电镜和在线电化学质谱的研究结果，我们发现锂氧电池充电电位的升高是由于循环过程中阴极副反应中CO2的积累导致放电产物由Li 2 O2转变为Li 2CO 3所致。我们进一步证明，当累积的CO2通过抽真空处理被排空时，循环Li-O2电池的性能可以完全恢复。因此，提出了在电池组装过程中预载CO2吸收剂（CaO）抑制CO2积累的策略。结果，有效地抑制了充电电位升高的现象，从而显著地改善了循环性能。与未预载CaO的Li-O 2电池相比，预载CaO的Li-O 2电池循环寿命提高了148%.该研究揭示了锂氧电池性能衰退的重要机理，并提出了提高锂氧电池循环寿命的有效途径，为长寿命锂氧电池的设计和制造提供了新的思路。
The increase in charge potential during discharge-charge cycling reduces severely the cycle life of a Li–O2battery, but its origin has not been fully understood yet. The current study focuses on revealing the intrinsic basis behind the increase of charge potential of a Li–O2battery and developing a strategy to inhibit this phenomenon. Based on results of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and online electrochemical mass spectroscopy, we find that the performance fading of a Li–O2battery evidenced by the increase in charge potential is caused by the discharge product transition from Li2O2to Li2CO3due to the accumulation of by-product CO2in cathode side reaction during cycling. We further demonstrate that the performance of a cycled Li–O2battery can be completely recovered when the accumulated CO2is evacuated by a vacuum pumping treatment. A strategy is therefore proposed to suppress the CO2accumulation by preloading a CO2absorbent agent (CaO) into Li–O2battery at its assemblage. As a result, the phenomenon of charge potential increase has been effectively inhibited, which improved significantly the cycleability. In comparison with a Li–O2battery without preloading CaO, the cycling life of the CaO preloaded Li–O2battery has been prolonged to 148%. This study reveals an important mechanism of performance fading of Li–O2battery and develops an efficient approach to increase the cycle life, which has thrown new insight into the design and construction of Li–O2batteries with long lifespan.