All-solid-state lithium batteries (ASSLBs) are being considered as the ultimate solution to the safety issue of current lithium ion batteries which use flammable organic electrolyte. The properties of the solid electrolyte, the most important component in ASSLBs, largely affect the electrode/electrolyte interfacial behavior and eventually the performance of ASSLBs. Sulfide electrolytes are considered as one of the most promising solid electrolyte for ASSLBs because of its excellent mechanical properties. However, they suffer from poor electrochemical stability and lithium dendrite formation. In this thesis, I demonstrated that the nitrogen-doped sulfide solid electrolyte system (75-1.5x)Li2S-25P2S5-xLi3N showed comprehensive performance improvements. The ionic conductivity is enhanced and the interfacial resistance between Li anode and solid electrolyte gets reduced by over 80%. The dendrite formation in solid electrolyte could also be effectively suppressed with the critical current density enhanced by 70%. The simultaneous improvement make it a promising solid electrolyte for ASSLBs.