天然黄铁矿热电池正极材料放电性能提升机制OA

The performance of cathode materials in thermal batteries has a decisive impact on the overall output characteristics and safety/stability of the batteries.As a typical high-reliability power source,thermal batteries are widely used in aerospace,weaponry,and emergency energy systems due to their long storage life,rapid activation,and wide environmental adaptability.Iron sulfides,such as FeS₂,have attracted considerable attention owing to their high theoretical specific capacity and abundant reserves.However,their intrinsically poor electronic conductivity and limited thermal stability constrain their further applications.This study focuses on natural pyrite.The natural pyrite sample is regulated through flotation,acid leaching,and heat treatment,and a synthetized high-purity FeS₂ serves as the reference.The structural features and electrochemical performance of the two are systematically compared.The X-ray fluorescence(XRF)results indicate that,in addition to the major elements Fe and S,the processed natural pyrite contains transition-metal impurities such as Ni and Cu.The X-ray diffraction(XRD)analysis confirms that its crystal structure is primarily composed of FeS ₂ and CuFeS ₂ phases.The thermogravimetric analysis(TGA)shows a decomposition temperature of approximately 450 ° C,evidencing the detrimental effect of impurities on the thermal stability.The electrochemical testing demonstrates that the natural pyrite sample supports stable discharge,with both average discharge voltage and specific capacity exceeding those of the synthesized FeS₂.The density functional theory calculations reveal that Ni/Cu dopants modulate the electronic density of states(DOS)and charge distribution of FeS₂,thereby facilitating the electron transport and optimizing the reaction pathways,which collectively enhance the performance.The research results reveal the synergistic regulation mechanism of trace transition metal doping in natural pyrite on the electrochemical behavior,providing new theoretical basis and experimental support for the performance optimization of FeS₂-based cathode materials in high-reliability thermal battery systems and high-value utilization of natural minerals in fields such as aerospace.