Na/NiCl_2电池正极材料表面形貌对其电化学性能影响

Effect of surface morphology on electrochemical performance of Ni/NiCl_2 cathode for Na/NiCl_2 batteries

研究以镍粉为主要原料,通过粉末烧结法制成Na/NiCl2电池用正极材料。采用扫描电子显微镜、自动压汞仪、比表面积分析仪及恒流充放电等测试手段,对此正极材料的物理性质和电化学性能进行了测试和表征。研究表明造孔剂碳酸氢铵(NH4HCO3)的含量对正极材料的表面形貌及其电化学性能有显著的影响。添加质量分数为20%的造孔剂于还原气氛下250℃保温半小时,700℃烧结1 h后所得正极,材料孔隙率高,孔径较大且一致,具有较好的充放电性能。材料的电化学性能与形貌参数有着直接联系,选用合适的造孔剂和用量可改善材料的表面形貌,进而可提高电池性能。

The cathode material of Na/NiCl2 batteries was prepared by powder sintering method with nickel powder as the main raw material.The physical properties and electrochemical performance of the specimen were characterized by scanning electron microscopy（SEM）,auto mercury injection apparatus,specific surface area analyzer and galvanostatic charge-discharge test.The results indicate that the pore-former content（NH4HCO3） has a distinct effect on the morphology and electrochemical performance of the cathode.The obtained material starting with 20% pore-former at 250 ℃ for 0.5 h,followed with 700 ℃ for 1 h under a reducing atmosphere shows a higher porosity,an optimal pore-size distribution and a good charge-discharge performance.It can be concluded that pore-former with proper amount can improve the surface morphology of the cathode and the electrochemical performance of Ni/NaCl cathode.