Abstract <p>Development of lithium all-solid-state power sources is a topical area of research worldwide. In order to solve the problem of high resistance at the cathode|solid electrolyte interface, it is proposed to introduce lithium-conducting glass 65Li₂O·27B₂O₃·8SiO₂ into the cathode material. Using X-ray diffraction and DSC data, it was established that there is no interaction between the cathode, sintering additive, and solid electrolyte up to 670°C. The introduction of 5 wt % glass followed by heat treatment resulted in a decrease in the resistance at the interface between cathode and solid electrolyte from 45 kOhm cm² at 300°C to ~0.8 and 0.1 kOhm cm² at 200 and 300°C, respectively. The charge-discharge process of all-solid-state power source is possible up to a current density of 100 μA/cm² at a temperature of 200°C. Long-term cycling of the cell at a current density of 20 μA/cm² at 200°C shows no deterioration in performance during the first 10 cycles.</p>