Search

Considerable research is being conducted on the use of FeF3 as a cathode replacement for FeS2 in thermal batteries. However, FeF3 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 FeF3, and the ratio was optimized. When acetylene black and MWCNTs were added separately to FeF3, the electrical conductivity increased, but the mechanical strength decreased. When acetylene black and MWCNTs were both added to FeF3, the FeF3/M1AB4 sample (with 1 wt.% MWCNTs and 4% AB) afforded a discharge capacity of approximately 74% of the theoretical capacity (712 mAh/g) of FeF3. Considering the electrical conductivity and mechanical strength, this composition was confirmed to be the most suitable. [ABSTRACT FROM AUTHOR]

Although numerous cathode materials with excellent properties have been developed for use in molten salt thermal batteries, similar progress is yet to be made with anode materials. Herein, a high-performance lithium-impregnated metal foam anode (LIMFA) is fabricated by impregnating molten lithium into a gold-coated iron–chrome–aluminium (FeCrAl) foam at 400 °C. A test cell employing the LIMFA FeCrAl anode exhibited a specific capacity of 2627 As g−1. For comparison, a cell with a conventional Li(Si) anode was also discharged, demonstrating a specific capacity of 982 As g−1. This significant improvement in performance can be attributed to the large amount (18 wt%) of lithium incorporated into the FeCrAl foam and the ability of the FeCrAl foam to absorb and immobilize molten lithium without adopting a cup system. For thermal batteries without a cup, the LIMFA FeCrAl provides the highest-reported specific capacity and a flat discharge voltage curve of molten lithium. After cell discharge, the FeCrAl foam exhibited no lithium leakage, surface damage, or structural collapse. Given these advantageous properties, in addition to its high specific capacity, LIMFA FeCrAl is expected to aid the development of thermal batteries with enhanced performance. [ABSTRACT FROM AUTHOR]

Herein, the discharge properties of lithium (Li) anode with FeS2 cathode system are investigated under different pressure loads, weight percent of Li, temperatures, and current densities to provide a fundamental understanding of the operational safety, electrochemical properties, and optimization parameters for Li anode‐based thermal batteries. The lithium anode was prepared via physically mixing Li with Fe powder. The Li−Si alloy, the most common anode for thermal batteries, was investigated simultaneously to show the clear distinction in electrochemical performance between the Li anode and Li−Si anode. For achieving high operational safety and discharge performance with Li anode, the recommended pressure load and weight percent of Li are below 6 kgf cm−2 and 15 wt%, respectively, to prevent any leakage or short‐circuiting problems. The discharge at 500 °C and 0.2–0.4 A cm−2 exhibits the optimal performance for the Li anode and FeS2 cathode system. Finally, the thermal batteries with 17 cells are manufactured to confirm the aforementioned parameters at −32 and 63 °C to demonstrate that the previous results coincide with the actual battery level experiments. Due to the intertwined nature of the parameters, the optimization should always be conducted in a holistic manner to obtain high‐performance thermal batteries for future military applications. [ABSTRACT FROM AUTHOR]

Hydrothermally synthesized homogeneous structures based on Ni, Mo, and S on Ni metal foam cathodes (NiMoSs) were characterized electrochemically. A NiMoS-containing cell exhibited a much higher specific capacity of 1534 A s g−1 than an FeS2 cathode, owing to its homogeneous structure, demonstrating promise for thermal battery applications. [ABSTRACT FROM AUTHOR]