Аннотация:The channels of single walled carbon nanotubes (SWCNT) were filled with eutectic composition consisting of PbSnF4 and SnF2. The nanocomposite was investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), X-ray energy dispersive (EDX) spectroscopy and Raman spectroscopy. The SnF2 and PbSnF4 nanocrystals form independent regions with disordered atomic region between them inside the SWCNT with a diameter of 20.0(3) Å. In the PbSnF4 region there are two separate fragments connected by a twinning plane. Structural models of the PbSnF4 twin nanocrystal and SnF2 nanocrystal inside the nanotube with chilarity (26,0) were constructed and computer modelling of TEM-image of E(PbSnF4;SnF2)@SWCNT nanocomposite was performed. Solid-state FIB with Ce as anode, dispersed E(PbSnF4;SnF2)@SWCNT + SnF2 as a composite-cathode and 95.03%LaF3+4.97%BaF2 electrolyte was investigated by the impedance spectroscopy and cyclic voltammetry. The current density reached ~0.6 A/m2 at 180ºC, the open circuit voltage of the pellet at room temperature was 1.9 V.