LaSr₂Mn₂O₇ Ruddlesden-Popper manganites for oxygen reduction and electrochemical capacitors

Qin Li^1,2，Meitian Guo²，Kaiyuan Wang²，Zhiqiang Wei²，Guoping Du¹，Guoguang Zhang²，Nan Chen¹

1. School of Materials Science and Engineering,Nanchang University2. School of Materials Science and Engineering,Nanchang Hangkong University

摘 要：LaSr₂ Mn₂ O₇,a Ruddlesden-Popper type bilayered perovskite,was investigated as oxygen catalyst for oxygen reduction reaction（ORR） and active electrode material for electrochemical capacitors in KOH solutions.XPS results show that Mn takes a mixed Mn²⁺,Mn³⁺and Mn⁴⁺valence state with an average valence of 3.4.As catalyst towards ORR,LaSr₂ Mn₂ O₇ and LaSr₂ Mn₂ O₇/acetylene black composite favor four electron pathways for ORR.LaSr₂ Mn₂ O₇/C composite shows a comparable onset potential for ORR to that of Pt/C electrode.The improved ORR activity of LaSr₂ Mn₂ O₇/acetylene black composite is attributed to the synergy between catalytic LaSr₂ Mn₂ O₇ and conductive acetylene black.As electrode material for electrochemical capacitors,LaSr₂ Mn₂ O₇ exhibits a maximum specific capacitance of 167.2 F/g with 62%faradic contribution at a scan rate of 1 mV/s in cyclic voltammetry test.

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