Research on Effective Oxygen Window Influencing the Capacity of Li-O-2 Batteries
Research on Effective Oxygen Window Influencing the Capacity of Li-O-2 Batteries
复制标题
有效氧窗口对Li-O-2电池容量影响的研究
DOI：
10.1021/acsami.6b02586
复制
发表时间：
2016
影响因子：
9.5
通讯作者：
Zhou Haoshen
中科院分区：
文献类型：
--
作者：
Jiang Jie;Deng Han;Li Xiang;Tong Shengfu;He Ping;Zhou Haoshen
Li-O2电池因其巨大的比能量而受到广泛关注。与锂离子电池的研究模式相似，目前普遍采用基于正极材料质量的比容量来评价锂氧电池的电化学性能。然而，输送量与有效质量之间的线性相关性这一前提容易被忽略。本文通过证实电池容量与LiCoO 2质量之间的线性关系，论证了以经典LiCoO 2为正极的锂离子电池采用比容量的合理性。同时测量了不同阴极质量的锂氧电池的放电容量，得到了非线性关联式。通过X射线衍射和现场气相色谱-质谱联用分析确定放电和充电产物，以确定反应机理。进一步研究了不同氧窗面积的锂氧电池的放电容量，发现电池容量随氧窗面积的增加而线性增加。采用扫描电子显微镜对放电电极进行观察，发现放电过程中Li 2 O2的沉积主要发生在暴露于氧气的电极区域，因此将该区域定义为容纳Li 2 O2的有效区域。此外，提出了一个合理的路线，形成有效面积的氧电极。这些结果提供的证据表明，有效面积是一个同样重要的因素决定细胞的能力。
Li–O2batteries have attracted extensive attention recently due to the extremely huge specific energy. Similar to research mode of Li-ion batteries, nowadays specific capacity based on the mass of cathode material is widely adopted to evaluate the electrochemical performance of Li–O2batteries. However, the prerequisite of linear correlation between the delivered capacity and active mass is easily neglected. In this paper, we demonstrate the rationality of specific capacity adopted in Li-ion batteries with classic LiCoO2cathode by confirming the linear correlation between cell capacity and LiCoO2mass. Delivered capacities of Li–O2batteries with different cathode masses are simultaneously measured and nonlinear correlation is obtained. The discharge and charge products are identified by X-ray diffraction and in situ gas chromatography-mass spectrometry analysis to ensure reaction mechanism. Discharge capacities of Li–O2batteries with various areas of oxygen window are further studied, which shows that cell capacity increases linearly with the area of oxygen window. Scanning electron microscopy is employed to observe the discharged electrode and shows that Li2O2deposition during discharge mainly occurs in the electrode area exposure to the oxygen, which is consequently defined as effective area for accommodating Li2O2. Moreover, a plausible route for formation of effective area in the oxygen electrode is proposed. These results provide evidence that effective area is an equally important factor determining cell capacity.