An all-solid-state lithium ion battery was constructed with a screen-printing process using Nb doped Li7La3Zr2O12 (LLZONb) as the solid electrolyte and Li3BO3 (LBO) as a solid electrolyte within the cathode layer. LBO is a lithium ion conductor that is chemically stable with the LiCoO2 (LCO) active cathode material and LLZONb. Sufficient interface contact between the cathode layer and the LLZONb solid electrolyte can be easily achieved with sintering LBO into the cathode layer by an annealing process. The resultant battery exhibited good electrochemical performance and a lower interfacial resistance comparable with that of lithium ion batteries with liquid organic electrolytes.