FeF/(Acetylene Black and Multi-Walled Carbon Nanotube) Composite for Cathode Active Material of Thermal Battery through Formation of Conductive Network Channels.

Considerable research is being conducted on the use of FeF as a cathode replacement for FeS in thermal batteries. However, FeF alone is inefficient as a cathode active material because of its low electrical conductivity due to its wide bandgap (5.96 eV). Herein, acetylene black and multi-walled carbon nanotubes (MWCNTs) were combined with FeF, and the ratio was optimized. When acetylene black and MWCNTs were added separately to FeF, the electrical conductivity increased, but the mechanical strength decreased. When acetylene black and MWCNTs were both added to FeF, the FeF/MAB sample (with 1 wt.% MWCNTs and 4% AB) afforded a discharge capacity of approximately 74% of the theoretical capacity (712 mAh/g) of FeF. Considering the electrical conductivity and mechanical strength, this composition was confirmed to be the most suitable.