Yun Young Jun, Kim Jin Kyu, Ju Ji Young, Unithrattil Sanjith, Lee Sun Sook, Kang Yongku, Jung Ha-Kyun, Park Jin-Seong, Im Won Bin, Choi Sungho
Advanced Battery Materials Research Group, Korea Research Institute of Chemical Technology, 141 Gajeongro, Yuseong, Daejeon, Republic of Korea.
School of Materials Science and Engineering and Optoelectronics Convergence Research Center, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea.
Dalton Trans. 2016 Mar 28;45(12):5064-70. doi: 10.1039/c5dt04975j.
Uniform surface conductive layers with porous morphology-conserved MnCo2O4 microspheres are successfully synthesized, and their electrochemical performances are thoroughly investigated. It is found that the microwave-assisted hydrothermally grown MnCo2O4 using citric acid as the carbon source shows a maximum Li(+) ion lithiation/delithiation capacity of 501 mA h g(-1) at 500 mA g(-1) with stable capacity retention. Besides, the given microsphere compounds are effectively activated as air cathode catalysts in Li-O2 batteries with reduced charge overpotentials and improved cycling performance. We believe that such an affordable enhanced performance results from the appropriate quasi-hollow nature of MnCo2O4 microspheres, which can effectively mitigate the large volume change of electrodes during Li(+) migration and/or enhance the surface transport of the LiOx species in Li-air batteries. Thus, the rationally designed porous media for the improved Li(+) electrochemical reaction highlight the importance of the 3D macropores, the high specific area and uniformly overcoated conductive layer for the promising Li(+) redox reaction platforms.
成功合成了具有多孔形态保留的 MnCo₂O₄ 微球的均匀表面导电层,并对其电化学性能进行了深入研究。结果发现,以柠檬酸为碳源通过微波辅助水热法生长的 MnCo₂O₄ 在 500 mA g⁻¹ 时显示出最大 Li⁺ 离子嵌入/脱嵌容量为 501 mA h g⁻¹,且容量保持稳定。此外,给定的微球化合物在锂氧电池中作为空气阴极催化剂被有效激活,具有降低的充电过电位和改善的循环性能。我们认为,这种性能提升且成本低廉的结果源于 MnCo₂O₄ 微球适当的准空心性质,它可以有效减轻 Li⁺ 迁移过程中电极的大体积变化,和/或增强锂空气电池中 LiOx 物种的表面传输。因此,为改善 Li⁺ 电化学反应而合理设计的多孔介质突出了 3D 大孔、高比表面积和均匀包覆的导电层对于有前景的 Li⁺ 氧化还原反应平台的重要性。