POLYMERIC COMPOSITE ELECTROLYTE BASED ON NASICON FOR SOLID-STATE LITHIUM BATTERIES

Анотація

A composite solid electrolyte based on the fluoropolymer Neoflon VT-475, the ionic liquid PYR14-TFSI, and the lithium salt LiTFSI has been developed and studied for use in solid-state lithium-ion batteries. As a lithium-conductive additive, nanoparticles of Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) with a NASICON-type structure were introduced into the electrolyte composition, providing three-dimensional channels for efficient lithium-ion migration. LATP was synthesized using a sol-gel method, which enabled the production of particles with high ionic conductivity and a stable crystalline structure. The methodology for fabricating the electrolyte in the form of a film is described, along with its characteristics, including elect­rochemical properties, which were investigated in laboratory battery prototypes with a LiFePO₄ (LFP) cathode and a Li₄Ti₅O₁₂ (LTO) anode modified with LATP. To improve interfacial contact between the solid electrolyte and the electrodes, a liquid-phase treatment was applied. The electrode surfaces were additionally impregnated with a polymer solution to enhance adhesion and interfacial contact. This approach reduced interfacial resistance, improved ion transport, and ensured stable performance during long-term cycling. The study showed that the developed prototypes with the composite solid electrolyte demonstra­ted specific capacities comparable to those of samples with liquid electrolytes under current loads up to 4C. Long-term cycling statistics indicated a high level of stability, with capacity degradation not exceeding 6% after 130 full charge-discharge cycles. The developed electrolyte is promising for use in solid-state lithium-ion batteries with improved performance, safety, and durability, as its structure and composition help reduce dendrite formation risk, enhance interfacial layer stability, and maintain high ionic conductivity even under high loads.