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.

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Phase transition behavior of silicone based liquid crystalline (LC) polymers with variable isotropic transition temperatures (T i ), synthesized from poly(methyl hydrosiloxane), 10-undecenoic acid based crosslinking agent and cholesterol based side chain mesogen, was studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) measurements. The chemical structure of the mesogenic monomer and the LC polymers were confirmed by Fourier transform infra-red (FT-IR) spectroscopy and 1 HNMR spectroscopy. DSC studies showed that the glass transition temperatures (T g ) and T i of the LC polymers decreased with increasing proportion of mesogenic crosslinking agent at its low proportion and at its higher proportion T i disappeared completely indicating that the polymeric chains had less chance to orient in the network structure. The results were consistent with the XRD and POM studies.

Thermal batteries are primary reserve batteries that use inorganic salt as electrolytes which are inactive at room temperature. The two principal heat sources that have been used in thermal batteries are heat paper and heat pellets. As soon as the heat paper, which is ignited by the initiator, in turn ignites the heat pellets, all the solid electrolytes are melted into excellent ionic conductors. However, the high combustion temperature by heat papers in thermal batteries causes thermal decomposition at the cathode, eventually leading to a thermal runaway. In this paper, we have attempted to prepare Zr/BaCrO4 heat papers coated with KCl molten salt. We have also investigated the effect of a molten salt coating on the heat papers through the thermal characteristics such as calorimetric value, combustion temperature and burning rate. The calorimetric value and combustion temperature of heat papers were reduced with an increase in the molten salt coating. As a result, the molten salt coating on heat papers greatly reduced risk of a thermal runaway and improved the stability of thermal batteries.