Performance Enhancement of FeS2 as Cathode Material for Thermal Batteries by Ball Milling After Adding Nano Vacancy-Containing WS2

Abstract

As the most commonly used cathode material for thermal batteries, FeS2 has the advantages of low price and abundant resources. However, the preparation of FeS2 by hydrothermal method is complicated, and FeS2 prepared by solid-phase method has a larger particle size. In this study, surface nanoscale FeS2 was synthesized using a milling method, and add nano WS2 with sulfur vacancies (WS2-Vs) to enhance thermal stability and conductivity. The results showed that the thermal decomposition temperature of FeS2 after adding 3% nano WS2-Vs ball milling for 4 h (FeS2@3%WS2-Vs-4h) was 100 °C higher than that of FeS2 ball milling for 4 h (FeS2–4h). In addition, the step-pulse discharge showed that single cell with FeS2@3%WS2-Vs-4h sample as the cathode active material has a lower internal resistance. Therefore, the discharge specific capacity of FeS2@3%WS2-Vs-4h is increased by 10.5% compared to pristine FeS2. The FeS2 doped with nano WS2-Vs retained the small particle size after ball milling, which not only did not excessively reduce the thermal stability, but also effectively improved its electrical conductivity with the increase of the discharge depth during the discharge process, thus achieve the effect of killing two birds with one stone. This work provides a novel cathode additive for thermal battery.