Effect of A-site substitution by Ca or Sr on the structure and electrochemical performance of LaMnO3 perovskite
Effect of A-site substitution by Ca or Sr on the structure and electrochemical performance of LaMnO3 perovskite
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Ca或Sr取代A位对LaMnO3钙钛矿结构和电化学性能的影响
DOI：
10.1016/j.electacta.2019.135489
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发表时间：
2020-02-01
影响因子：
6.6
通讯作者：
Jiang, Guo Hua
中科院分区：
文献类型：
--
作者：
Ma, Pian Pian;Lu, Qiu Ling;Jiang, Guo Hua
研究了Ca或Sr取代a位对LaMnO3 （LMO）钙钛矿晶体结构和电化学性能的影响。La0.85Ca0.15MnO3 （LCM）保持与母体LMO相同的正交结构，而La0.85Ca0.15MnO3 （LSM）则转变为菱面体结构。根据修正后的阴离子插层机理，具有更多氧空位的a位取代物比母体LMO样品更有利于氧插层，电化学性能得到显著优化。LCM和LSM电极在水溶液中在0.5 mA cm（-2）时的比电容分别为140.5 mF cm（-2）和129.0 mF cm(-2)，是LMO的4倍。LCM电极由于具有更细的形貌、更低的离子扩散阻力、更高的氧空位浓度和更充分地利用钙钛矿体结构而具有最高的电容性能。此外，LCM//LCM对称超级电容器的能量密度为29.7 mu Wh。粉末密度为500 μ W cm（-2）。我们的工作表明，Ca或Sr取代a位的组合物在超级电容器中具有很大的应用潜力，并且有望进一步优化。(C) 2019 Elsevier Ltd.版权所有。
The effect of A-site substitution by Ca or Sr on the crystal structure and electrochemical performance of LaMnO3 (LMO) perovskite have been investigated. La0.85Ca0.15MnO3 (LCM) keeps the same orthorhombic structure with the parent LMO composition, while La0.85Ca0.15MnO3 (LSM) transforms to rhombohedral structure. The A-site substituted compositions with more oxygen vacancies are more beneficial to the oxygen intercalation than the parent LMO sample according to the modified anion-intercalation mechanism, and the electrochemical performance is significantly optimized. LCM and LSM electrodes exhibit a specific capacitance of 140.5 mF cm(-2) and 129.0 mF cm(-2) at 0.5 mA cm(-2) in an aqueous electrolyte, respectively, which are four times larger than that of LMO. LCM electrode yields the highest capacitance behavior because of the finer morphology, lower ion diffusion resistance, higher concentration of oxygen vacancy and fuller utilization of the perovskite bulk structure. In addition, LCM//LCM symmetric supercapacitor exhibits an energy density of 29.7 mu Wh.cm(-2) at a powder density of 500 mu W cm(-2). Our work indicates that A-site substituted compositions by Ca or Sr exhibit great potential in the supercapacitor applications, and further optimization is expected. (C) 2019 Elsevier Ltd. All rights reserved.