热电池新型正极材料的制备与性能研究

Preparation and performances of new cathode materials for thermal battery

采用溶剂热法和高温煅烧法制备了FeF_(3)-FeF_(2)正极材料,并对其物理和电化学性能进行了表征。结果表明:FeF_(3)-FeF_(2)正极材料的比表面积为11.8 m^(2)/g,远大于FeS_(2)的比表面积(0.5 m^(2)/g)。FeF_(3)-FeF_(2)正极材料的初始热分解温度为850℃,比FeS_(2)高出300℃,比CoS_(2)高出200℃。FeF_(3)-FeF_(2)单体电池的空载电压为3.22 V,远高于FeS_(2)的空载电压(2.05 V)。LiB/LiF-LiCl-Li_(2)SO_(4)/FeF_(3)-FeF_(2)单体电池在电流密度150 mA/cm^(2)下的初始放电电压为2.65 V,截止电压1.5 V,能够放电308 s,放电比容量达到160.4 mAh/g,较LiCl-KCl和LiF-LiCl-LiBr电解质体系提高75.3%和43.5%,表现出更长的工作时间。因此,对于高电压、高比能量和高比功率热电池的研制,FeF_(3)-FeF_(2)是一种极具前景的热电池正极材料。

FeF_(3)-FeF_(2)cathode material was prepared by solvothermal and high temperature calcination methods,and its physical and electrochemical properties were characterized.The test results show that the specific surface area of FeF_(3)-FeF_(2)cathode materials is 11.8 m^(2)/g,which is much larger than FeS_(2)(0.5 m^(2)/g).The initial thermal decomposition temperature of FeF_(3)-FeF_(2) cathode materials is 850℃,which is about 300℃higher than FeS_(2) and about 200℃higher than CoS_(2).The no-load voltage of FeF_(3)-FeF_(2) single cell battery is 3.22 V,which is much higher than the no-load voltage of FeS_(2)(2.05 V).The initial discharge voltage of LiB/LiF-LiCl-Li_(2)SO_(4)/FeF_(3)-FeF_(2) single cell battery is 2.65 V at the current density of 150 mA/cm^(2).When the cut-off voltage is 1.5 V,it can discharge for 308 s.The specific discharge capacity of LiB/LiF-LiCl-Li_(2)SO_(4)/FeF_(3)-FeF_(2) single cell battery reaches 160.4 mAh/g,which is 75.3%and 43.5%higher than the LiCl-KCl and LiF-LiCl-LiBr electrolyte systems,exhibiting a longer working time.Therefore,for the development of high voltage,high specific energy,and high specific power thermal batteries,FeF_(3)-FeF_(2) is a promising cathode material for thermal batteries.