Liu Pan, Han Jiuhui, Guo Xianwei, Ito Yoshikazu, Yang Chuchu, Ning Shoucong, Fujita Takeshi, Hirata Akihiko, Chen Mingwei
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200030, P.R. China.
Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.
Sci Rep. 2018 Feb 16;8(1):3134. doi: 10.1038/s41598-018-21503-w.
Rechargeable non-aqueous lithium-oxygen batteries with a large theoretical capacity are emerging as a high-energy electrochemical device for sustainable energy strategy. Despite many efforts made to understand the fundamental Li-O electrochemistry, the kinetic process of cathodic reactions, associated with the formation and decomposition of a solid LiO phase during charging and discharging, remains debate. Here we report direct visualization of the charge/discharge reactions on a gold cathode in a non-aqueous lithium-oxygen micro-battery using liquid-cell aberration-corrected scanning transmission electron microscopy (STEM) combining with synchronized electrochemical measurements. The real-time and real-space characterization by time-resolved STEM reveals the electrochemical correspondence of discharge/charge overpotentials to the nucleation, growth and decomposition of LiO at a constant current density. The nano-scale operando observations would enrich our knowledge on the underlying reaction mechanisms of lithium-oxygen batteries during round-trip discharging and charging and shed lights on the strategies in improving the performances of lithium-oxygen batteries by tailoring the cathodic reactions.
具有大理论容量的可充电非水锂氧电池正成为可持续能源战略中的一种高能电化学装置。尽管人们为理解锂氧基本电化学做出了许多努力，但与充放电过程中固态LiO相的形成和分解相关的阴极反应动力学过程仍存在争议。在此，我们报告了使用液池像差校正扫描透射电子显微镜（STEM）结合同步电化学测量，对非水锂氧微型电池中金阴极上的充放电反应进行直接可视化。通过时间分辨STEM进行的实时和实空间表征揭示了在恒定电流密度下，放电/充电过电位与LiO的成核、生长和分解之间的电化学对应关系。纳米尺度的原位观察将丰富我们对锂氧电池往返充放电过程中潜在反应机制的认识，并为通过调整阴极反应来提高锂氧电池性能的策略提供启示。
