Research on La- Mg- Ni system A2B7- type hydrogen storage alloy surface coating NAFION and electrochemical performance
WANG Hao1, LUO Yong- chun1,2, DENG An- qiang1, ZHAO Lei1
1. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, Gansu, China 2. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou 730050, Gansu, China
Abstract：La- Mg- Ni- based hydrogen storage alloy surface was coated NAFION using simple evaporation solvent phase conversion method. The effects of different concentrations of NAFION solution on the surface and electrochemical properties of La- Mg- Ni based hydrogen storage alloys were investigated. The results show that by evaporating the solvent, NAFION can form different forms of NAFION functional coating on the surface of hydrogen storage alloy. With the decrease of the concentration, The NAFION formed on the surface of the alloy particles is changed from a dispersed and raised white flakes to a thin, well- spread film, but the film can not completely coated alloy particles. Electrochemical performance test results show that the cycle stability of the alloy after coated NAFION is improved. When the NAFION dilution ratio is 1∶5, alloy electrode discharge capacity is the largest (387. 3 mA·h/g) and the cycle stability is the best, after 100 times charge and discharge cycle, the alloy capacity retention rate S100 reached 89%, which is best bare alloy. After the surface coating of NAFION, the high current discharge performance of the alloy electrode was significantly decreased, and the HRD900 was reduced from 81. 6% of the bare alloy to 68. 1% after the coating. The increase of the surface electron exchange resistance (or the exchange current density I0 decreases) at the time of the alloy electrode reaction is one of the main factors affecting the high magnification discharge performance of the coated alloy.
王浩，罗永春 ，邓安强，赵磊. La- Mg- Ni系A2B7型储氢合金表面包覆NAFION及其电化学性能研究[J]. , 2018, 25(1): 23-29.
WANG Hao, LUO Yong- chun,, DENG An- qiang, ZHAO Lei. Research on La- Mg- Ni system A2B7- type hydrogen storage alloy surface coating NAFION and electrochemical performance. , 2018, 25(1): 23-29.
2018, Vol. 25 
