2019 Volume 127 Issue 1 Pages 18-21
All-solid-state Li-ion battery is expected as the post Li-ion battery because of its high reliability and safety. However, the biggest issue for the all-solid-state Li-ion battery is the interfacial resistance between electrode and electrolyte rather than the bulk ionic conductivity of the solid electrolyte. In order to reduce the interfacial resistance, we recently adopted a new concept, “single-phase all-solid-state battery”, which is made of a single material. In principle, single-phase all-solid-state battery has low interfacial resistance between the solid electrolyte and electrodes, because the solid electrolyte and electrodes are same material. Here, the electrochemical properties of single-phase all-solid-state battery based on Li1.5Cr0.5Ti1.5(PO4)3 and the effect of Li3BO3 additive as flux to Li1.5Cr0.5Ti1.5(PO4)3 are shown. The pellet of Li1.5Cr0.5Ti1.5(PO4)3 with Li3BO3 additive showed higher density by filling the voids of Li1.5Cr0.5Ti1.5(PO4)3. As the result of the low electronic conductivity of Li3BO3, the overpotential was increased. However, the electron leakage was suppressed. On the other hand, the operation voltage and the reversible capacity were improved due to the high lithium-ionic conductivity of Li3BO3. It was found that Li3BO3 additive is useful for the improvement of the single-phase battery.