锂空气电池用碳纳米管/钴锰氧化物复合电极材料的制备及电化学性能

采用沉淀法合成了不同钴锰含量的碳纳米管(CNTs)/钴锰氧化物纳米复合材料. 利用XRD、SEM、TEM、BET和FT-IR等方法对材料进行了表征, 考察了不同复合材料对锂空气电池放电及充电过程的影响, 同时对循环性能进行了研究. 结果表明: 钴锰比例为4:0与0:4时, 产物为CNTs/Co₃O₄与CNTs/Mn₃O₄, 钴锰比例为3:1、2:2、1:3时, 产物为CNTs/(Co, Mn)(Co, Mn)₂O₄。产物具有良好的分散性能, 氧化物负载在碳管表面, 其中CNTs/Mn₃O₄的分散性能最好。随着锰含量的增加, 电池的放电性能提高, CNTs/Mn₃O₄的放电电压达到2.92 V。随着钴含量的增加, 电池的充电性能提高, 充电电压最低为3.80 V。钴锰比为3:1时的产物充放电过电势(△V)仅为1.05 V, 5次循环后依然保持着良好的放电性能。

Synthesis and Electrochemical Performance of Carbon Nanotubes/Cobalt Manganese Oxides Composite Materials for Lithium Air Batteries

Carbon nanotubes/cobalt manganese oxides composites with different Co/Mn ratios were prepared by precipitation method. The as-prepared products were characterized by XRD, SEM, TEM, BET, FT-IR, discharge performance, charge performance and cycle profiles. The results show that the products are CNTs/Co₃O₄ and CNTs/Mn₃O₄ when Co/Mn ratios are 4:0 and 0:4, respectively, while CNTs/(Co, Mn)(Co, Mn)₂O₄ is obtained at Co/Mn ratios of 3:1, 2:2 and 1:3. The products show high dispersion with oxides attaching to CNTs closely, and CNTs/Mn₃O₄ has the best morphology performance. With increasing content of Mn, the discharge performance improves. CNTs/Mn₃O₄ has the highest discharge voltage of 2.92 V. For charge processes, the product with higher content of Co reveals better charge properties. The lowest voltage is about 3.8 V. Meanwhile, the product with Co/Mn ratio of 3:1 has a minor charge-discharge voltage difference(△V) of 1.05 V, which still keeps excellent electrochemical performance after 5 charge-discharge cycles.