阴离子型配体镍基正极材料在水系碱性电池中的储OH^(-)性能

OH^(-)Storage Properties of Anion-Ligand Nickel-Based Cathode Materials in Aqueous Alkaline Batteries

采用电沉积法制备了Ni(OH)_(2)、Ni_(3)N、Ni_(3)S_(2)3种不同阴离子型配体的镍基化合物,并对比了其在水系碱性电池中的储OH^(-)性能。研究发现,在循环过程中,Ni_(3)S_(2)表现出最高的初始放电容量(230 mAh/g),扫描200圈后为115 mAh/g;而Ni_(3)N表现出最高的库仑效率(98.5%)。分析其原因,典型的电池型Ni(OH)_(2)材料在OH^(-)脱嵌过程中伴随着晶体结构的坍塌,造成循环性能和离子迁移能力快速下降;而兼具赝电容特性的Ni_(3)S_(2)和Ni_(3)N因无定形的脱嵌过程缓解了结构的坍塌,从而获得较高的电化学储OH^(-)性能。

Three different anion-ligand nickel-based cathode materials,Ni(OH)_(2),Ni_(3)S_(2) and Ni_(3)N,were prepared based on simple electrodeposition,and their OH^(-)storage properties were explored for comparison in aqueous alkaline batteries.It is found that Ni_(3)S_(2) has the highest initial discharge capacity of 230 mAh/g during cycling and half of it was retained after 200 cycles,while Ni_(3)N exhibits the highest coulombic efficiency of 98.5%among them because of its excellent conductivity.These phenomena are analysed as follows:as a typical battery-type material,Ni(OH)_(2) suffers structural collapse in the process of OH^(-)de-intercalation during cycling,which results in the rapid decrease of cycling performance and ion diffusion ability.Conversely,Ni_(3)S_(2) and Ni_(3)N,which have the characteristics of pseudocapacitors,alleviate the collapse because of the amorphous de-intercalation process,therefore the better OH^(-)storage performances were achieved.