Using elastin protein to develop highly efficient air cathodes for lithium-O sub(2) batteries

• Published in: Nanotechnology 2016-01, Vol.27 (4), p.1-10
• Main Authors: Guo, Guilue, Yao, Xin, Ang, Huixiang, Tan, Huiteng, Zhang, Yu, Guo, Yuanyuan, Fong, Eileen, Yan, Qingyu
• Format: Article
• Language: English
• Subjects: Acid leaching; Catalysis; Catalysts; Cathodes; Current density; Discharge; Elastin; Proteins
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/27/4/045401

Transition metal-nitrogen/carbon (M-N/C, M = Fe, Co) catalysts are synthesized using environmentally friendly histidine-tag-rich elastin protein beads, metal sulfate and water soluble carbon nanotubes followed by post-annealing and acid leaching processes. The obtained catalysts are used as cathode materials in lithium-O sub(2) batteries. It has been discovered that during discharge, Li sub(2)O sub(2) nanoparticles first nucleate and grow around the bead-decorated CNT regions (M-N/C centres) and coat on the catalysts at a high degree of discharge. The Fe-N/C catalyst-based cathodes deliver a capacity of 12 441 mAh g super(-1) at a current density of 100 mA g super(-1). When they were cycled at a limited capacity of 800 mAh g super(-1) at current densities of 200 or 400 mA g super(-1), these cathodes showed stable charge voltages of ~3.65 or 3.90 V, corresponding to energy efficiencies of ~71.2 or 65.1%, respectively. These results are considerably superior to those of the cathodes based on bare annealed CNTs, which prove that the Fe-N/C catalysts developed here are promising for use in non-aqueous lithium-O sub(2) battery cathodes.