Zhang Xiuhui, Chen Xiang, Chen Chunguang, Liu Tie, Liu Mengmeng, Zhang Congcong, Huang Tao, Yu Aishui
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University Shanghai 200433 China.
Laboratory of Advanced Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University Shanghai 200433 China
RSC Adv. 2018 Nov 29;8(70):39829-39836. doi: 10.1039/c8ra08763f. eCollection 2018 Nov 28.
Suitable catalysts and reasonable structures for oxygen electrodes can effectively improve the electrochemical performance of lithium-oxygen batteries. In this work, ruthenium oxide modified boron-doped hierarchically porous reduced graphene aerogels (RuO-B-HRG) are prepared by a sol-gel and subsequent low temperature annealing method and used as oxygen electrodes. The RuO nanoparticles (5-10 nm) are uniformly anchored in the three-dimensional B-HRG continuous electric network. The RuO-B-HRG aerogel possesses a large specific surface area (287.211 m g) and numerous mesopores and micropores. The pores facilitate electrolyte impregnation and oxygen diffusion, and they provide greatly increased accommodation space for the discharge products. Electrochemical tests show that the RuO-B-HRG/KB enables the electrode overpotential to decrease, and the rate capability and the cycling stability are enhanced compared with pure HRG. The enhanced performance is ascribed to the bifunctional catalytic activity of RuO-B-HRG and its unique three-dimensional porous architecture. The method is proved to be an effective strategy to combine porous carbon materials and nanoscale catalysts as electrodes for Li-O batteries.
适用于氧电极的催化剂和合理结构能够有效提升锂氧电池的电化学性能。在本研究中，通过溶胶-凝胶法及后续低温退火法制备了氧化钌修饰的硼掺杂分级多孔还原氧化石墨烯气凝胶（RuO-B-HRG）并将其用作氧电极。氧化钌纳米颗粒（5-10纳米）均匀地锚定在三维B-HRG连续导电网络中。RuO-B-HRG气凝胶具有较大的比表面积（287.211平方米/克）以及大量的中孔和微孔。这些孔隙有利于电解质的浸渍和氧气的扩散，并且为放电产物提供了大幅增加的容纳空间。电化学测试表明，RuO-B-HRG/KB能使电极过电位降低，与纯HRG相比，倍率性能和循环稳定性均得到增强。性能的提升归因于RuO-B-HRG的双功能催化活性及其独特的三维多孔结构。该方法被证明是一种将多孔碳材料和纳米级催化剂结合作为锂氧电池电极的有效策略。
