The Superior Electrochemical Property of LiTFSI@(Ba+Nb)-co-doped Li7La2.75Ba0.25Zr1.75Nb0.25O12@PEO Composite Membrane in All-Solid-State Lithium Battery

It is popular to choose the cubic phase Li7La3Zr2O12(c-LLZO) to synthesize the PEO-based complex membrane in all-solid-state battery. In this work, Ba/Nb elements were selected to achieve Li6.75La3Zr1.75Nb0.25O12 (LLZNO) and Li7La2.75Ba0.25Zr1.75Nb0.25O12 (LLBZNO) with high ion conductivity, which effectively enhance the electrochemical properties of the complex solid membrane and the all-solid-state battery. The higher ion mobility of LLBZNO compared to that of LLZNO and LLZO is calculated by ab-initio molecular dynamics (AIMD) simulation and further confirmed by experiments. Results show that the cubic phase of LLBZNO is more stable than that of LLZNO. The complex membrane of LLBZNO@ polyethylene oxide (PEO) (CPE-2-x wt%) exhibits the better electrochemical properties than LLZNO@PEO (CPE-1-x wt%) complex membrane. In detail, the CPE-2–10 wt% has the outstanding lithium transfer number ({t}_{{{Li}}^{+}}) of 0.63, as well as the excellent compatibility with lithium metal anode. In addition, at 0.1 mAcm−2, the lithium/CPE-2–10 wt%/lithium symmetric cell remains stable after 1000 h. It is LLBZNO that makes LLBZNO@PEO composite polymer electrolyte(CPE) the potential for the application in all-solid-state lithium battery.