镍氢电池正极大电流充放电性能及最佳配方

摘要

Two layered double hydroxides, [ Ni4 Al ( OH) 10 ] OH and [ Co4 Al ( OH) 10 ] NO3, were synthesized by chemical co-precipitation. The former was used as the active material and the latter as well as graphite were used as the conductive additives, respectively. The optimum ratio of the three materials in a positive electrode was estimated through the simplex-centrqid design to improve the charge/discharge properties efficiently at a high current density. When the mass fractions of [Ni4Al(OH)10]OH, [Co4Al(OH) 10]NO3 and graphite are 64.45% , 12. 27% and 23. 28% , respectively, the discharge capacity can retain 270. 5 mA·h/g(88. 7% of the maximum) after 200 cycles at a current density of 800 mA/g.%采用化学共沉淀法制备了镍铝和钴铝2种层状氢氧化物[ Ni4Al(OH)10]OH和[Co4Al(OH)10]NO3.将前者作为电极活性材料,后者及石墨作为正极导电添加剂,通过单纯形重心设计研究了正极中3种物质的最佳配比,使其大电流充放电性能得到有效地提高.结果表明,电极的性能与电极配方密切相关.当[ Ni4Al(OH)10]OH、[ Co4Al(OH)10]NO3和石墨的质量分数分别为64.45％、12.27％和23.28％时,电极在经过800 mA/g 200次充放电后的放电比容量最高,为270.5 mA· h/g(最大值的88.7％)；[Co4Al(OH)10]NO3的加入使电极的放电比容量和循环寿命得到了显著的提高.