中國有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 1 January 2014 |
（1. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
2. National Key Laboratory of Science and Technology on Power Sources,
Tianjin Institute of Power Sources, Tianjin 300384, China;
3. Key Laboratory of Advanced Energy Materials Chemistry, Ministry of Education,
Nankai University, Tianjin 300071, China）
Abstract:The hollow α-MnO2 nanoneedle-based microspheres coated with Pd nanoparticles were reported as a novel catalyst for rechargeable lithium-air batteries. The hollow microspheres are composed of α-MnO2 nanoneedles. Pd nanoparticles are deposited on the hollow microspheres through an aqueous-solution reduction of PdCl2 with NaBH4 at room temperature. The results of TEM, XRD, and EDS show that the Pd nanoparticles are coated on the surface of α-MnO2 nanoneedles uniformly and the mass fraction of Pd in the Pd-coated α-MnO2 catalyst is about 8.88%. Compared with the counterpart of the hollow α-MnO2 catalyst, the hollow Pd-coated α-MnO2 catalyst improves the energy conversion efficiency and the charge-discharge cycling performance of the air electrode. The initial specific discharge capacity of an air electrode composed of Super P carbon and the as-prepared Pd-coated α-MnO2 catalyst is 1220 mA·h/g (based on the total electrode mass) at a current density of 0.1 mA/cm2, and the capacity retention rate is about 47.3% after 13 charge-discharge cycles. The results of charge-discharge cycling tests demonstrate that this novel Pd-coated α-MnO2 catalyst with a hierarchical core-shell structure is a promising catalyst for the lithium-air battery.
Key words: lithium-air battery; composite catalyst; nanoneedle-based hollow microsphere; core-shell structure
