Lanthanum Manganite-based Air Electrode Catalysts and Their Application to Lithium-air Batteries: Effects of Carbon Support Oxidation
Lanthanum Manganite-based Air Electrode Catalysts and Their Application to Lithium-air Batteries: Effects of Carbon Support Oxidation
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DOI：
10.5796/electrochemistry.18-00034
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发表时间：
2018-09
期刊：
影响因子：
2.5
通讯作者：
Morihiro Saito;Y. Tachikawa;Taichi Fujinami;Kento Mikami;Yoshiya Hayashi;H. Shiroishi;D. Streich;Erik J. Berg;P. Novák
中科院分区：
文献类型：
--
作者：
Morihiro Saito;Y. Tachikawa;Taichi Fujinami;Kento Mikami;Yoshiya Hayashi;H. Shiroishi;D. Streich;Erik J. Berg;P. Novák
制备了酸处理的凯金黑(a-KB)碳载体，考察了碳表面的氧化对La0.6Sr0.4MnO3(LSM)纳米粒子分布及其与碳载体偶联的影响。制备了30wt.%LSM负载的a-Kb(LSM/a-Kb)材料作为二次锂空气电池(LAB)空气电极催化剂。A-KB表面含有大量含氧(C-O，CoO)官能团，形成了较小的LSM纳米粒子，与原始的KB载体相比，增强了碳载体上的均一性。结果形成了C-O-Mn键，增加了Mn的氧化态，同时增强了共轭作用，从而提高了催化活性。此外，充电过程中过电位降低(Li2O2分解)。此外，LSM/a-Kb增强了实验室测试单元的可循环性。扫描电子显微镜观察表明，与LSM/KB相比，LSM/a-KB能有效地分解Li2O2沉积层，即使在第15次充电循环之后也是如此。LSM/a-KB空气电极在放电后表现出更均匀和更小尺寸(和/或无定形)的Li2O2沉积。因此，碳表面的氧化导致LSM纳米粒子在a-KB表面的分布和结合增强，影响了在放电过程中沉积在载体上的Li2O2的均匀性，导致其在随后的充电过程中容易分解。©日本电化学会，版权所有。
Acid-treated Ketjen Black (a-KB) carbon supports were prepared to investigate how oxidation of the carbon surface influences La0.6Sr0.4MnO3 (LSM) nanoparticle distribution, and conjugation to the carbon support. 30wt.% LSMloaded a-KB (LSM/a-KB) materials were prepared as air-electrode catalysts for rechargeable lithium-air batteries (LABs). a-KB exhibited a significant degree of O-containing (C-O, COO) surface functional groups, which resulted in the formation of smaller LSM nanoparticles and enhanced homogeneity over the carbon support when compared with the pristine KB support. Consequently, C-O-Mn bonds were formed, which increased the Mn oxidation state, and concomitantly enhanced conjugation resulting in improved catalytic activity. Additionally, the overpotential was reduced during charging (Li2O2 decomposition). Furthermore, LSM/a-KB enhanced the cyclability of the LAB test cell. Scanning electron microscopy observations revealed that LSM/a-KB efficiently decomposed the Li2O2 deposition layer, even after the 15th charge cycle when compared with LSM/KB. The LSM/a-KB air-electrode exhibited a more homogeneous and smaller-sized (and/or amorphous) Li2O2 deposition after discharging. Therefore, the oxidation of the carbon surface, resulting in enhanced LSM nanoparticle distribution on, and conjugation to, the a-KB surface, influences the homogeneity of the Li2O2 deposition onto the support during the discharge process leading to its facile decomposition during the following charge process. © The Electrochemical Society of Japan, All rights reserved.