Remarkable improvement of cyclic stability in Li-O-2 batteries using ruthenocene as a redox mediator
Remarkable improvement of cyclic stability in Li-O-2 batteries using ruthenocene as a redox mediator
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使用二茂钌作为氧化还原介体显着改善 Li-O-2 电池的循环稳定性
DOI：
10.1016/j.cclet.2019.11.046
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发表时间：
2020
影响因子：
9.1
通讯作者：
He Qinggang
中科院分区：
文献类型：
--
作者：
Zhu Cuicui;Wang Yiping;Shuai Ling;Tang Yizhao;Qiu Ming;Xie Jian;Liu Jia;Wen Wen;Chen Hengquan;Nan Suifei;Dou Mei;He Qinggang
非水Li-O2电池以其理论比能量密度引起了人们的关注。但由于Li_2O_2不易分解，充电过电势较高，循环寿命较差。为此，对阴极上的各种催化剂进行了研究。与多相固体催化剂相比，可溶性催化剂通过可逆的氧化还原对实现了电子的更快、更有效的传输。在这里，我们首先报道了Ruthenocene(RUC)作为锂-O2电池中的一种移动氧化还原介体。0.01Mol/L溶液中的RUC有效地降低了充电电压610 mV。此外，RUC使用简单的凯金黑(KB)阴极，将循环寿命提高了四倍(最高可达83次)。扫描电子显微镜、X射线光电子能谱和X射线衍射仪的结果表明，充电后的放电产物残留物积累较少。为了验证介体的反应机理，基于密度泛函理论给出了可能的反应途径的自由能分布。
Nonaqueous Li–O2batteries attract attention for their theoretical specific energy density. However, due to the difficulty of decomposition of Li2O2, Li–O2batteries have high charge overpotential and poor cycling life. So all kinds of catalysts have been studied on the cathode. Compared to heterogeneous solid catalysts, soluble catalysts achieve faster and more effective transport of electrons by reversible redox pairs. Here, we first report ruthenocene (Ruc) as a mobile redox mediator in a Li–O2battery. 0.01 mol/L Ruc in the electrolyte effectively reduces the charging voltage by 610 mV. Additionally, Ruc greatly increases the cycling life by four-fold (up to 83 cycles) with a simple ketjen black (KB) cathode. The results of SEM, XPS and XRD confirm that less discharge product residue accumulated after recharge. To verify the reaction mechanisms of the mediator, free energy profiles of the possible reaction pathways based on DFT are provided.