High-specific capacity thermal battery cathode Fe and Ni doped CoS2 by enhanced thermal stability and conductivity.

[Display omitted] • The single-phase structure of Fe 0.1 Co 0.8 Ni 0.1 S 2 was successfully prepared by doping Fe and Ni in CoS 2 by solid phase method. • Fe 0.1 Co 0.8 Ni 0.1 S 2 has excellent discharge performance as a positive electrode material for thermal batteries. • The mechanism of enhancing the electrochemical performance of CoS2 by doping was revealed. • There is a synergistic effect between Fe, Ni and Co. CoS 2 can meet the strict requirements of high probability output capacity and high energy output capacity of thermal batteries in modern weaponry thanks to its advantages of low resistivity and high thermal decomposition temperature combined with a full Li+ conductive electrolyte. Nevertheless, CoS 2 has the limitations of a low voltage platform and theorical capacity. In this case, Fe and Ni are doped into the CoS 2 lattice through low-temperature solid-phase sintering to synthesize Fe 0.1 Co 0.8 Ni 0.1 S 2 with a single-phase structure. Fe 0.1 Co 0.8 Ni 0.1 S 2 generated by the solid phase method has higher thermal stability, which can reduce the high temperature thermal shock at the immediate start of the thermal battery and assure the safety of the thermal battery in operation. Meanwhile, the mass loss of Fe 0.1 Co 0.8 Ni 0.1 S 2 at 615 °C is only 5 %, allowing it to discharge at the maximum effective mass at the normal operating temperature(∼500 °C). Because of the synergistic action of Fe2+, Ni2+, and Co2+ in the discharge process, the discharge voltage of CoS 2 increases significantly, giving CoS 2 higher specific energy. The simultaneous boost in specific energy and specific capacity indicates that doping has been highly successful in modifying CoS 2 , making CoS 2 more appropriate for the use of high current and long-life thermal cell systems. [ABSTRACT FROM AUTHOR]