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Solid-state batteries: Tantalum-doped electrolytes revolutionize energy density and safety

The breakthrough application of tantalum materials in the field of solid-state batteries focuses on the research and development of oxide solid electrolytes. Although the traditional lithium lanthanum zirconium oxide (LLZO) electrolyte has wide temperature adaptability (-20℃ to 200℃) and a high electrochemical window (5V), its lithium ion conductivity is only one-tenth of that of sulfide electrolytes, and the sintering temperature exceeds 1100℃, making it difficult to industrialize. Through tantalum doping, the research team has achieved three key breakthroughs:

1. The ion transmission efficiency has increased: The 5d orbit of the tantalum atom is strongly coupled with the 2s orbit of the lithium ion, constructing a superionic transmission channel with a diameter of 0.45nm, and the lithium ion migration energy barrier has dropped from 0.65eV to 0.32eV, and the conductivity has broken through to 10^-3 S/cm, which is comparable to sulfide electrolytes.
2. Preparation process optimization: the sintering temperature is reduced from 1100℃ to 900℃, the time is shortened by 40%, the material density is increased to 96.8%, and the production cost is greatly reduced.
3. Performance and safety leap: the energy density of the soft-pack battery equipped with tantalum-doped LLZO electrolyte reaches 425Wh/kg (67% higher than the mainstream ternary battery), the low-temperature discharge capacity retention rate of -20℃ is 85%, and the capacity decay after 500 cycles at 60℃ is only 12%. Its thermal decomposition temperature exceeds 800℃, there is no fire or explosion in the needle puncture test, and it can still work normally with 30% deformation in the extrusion test. It has great potential in energy storage power stations, aerospace and other fields.
Industrialization progress: Haike Xinyuan and other companies have advanced tantalum-doped LLZO electrolytes to the laboratory stage and plan to cooperate with battery manufacturers to carry out demonstration projects. Ganfeng Lithium and other companies provide raw material guarantees for the solid-state battery industry chain through cooperative development of niobium and tantalum ore resources.