Preparation of high ionic conducting Sc and B co-doped NASICON-type Li1.3Al0.3Ti1.7(PO4)3 and its application in PVDF-HFP-based solid hybrid electrolytes for lithium-ion batteries

Sc and B doping enlarges the electrolyte lattice and reduces grain boundaries. • The LASBTP003 electrolyte shows an optimal ionic conductivity of 0.882 mS/cm. • PVDF-HFP-LITFSI-SN-10LASBTP003 SCE displays enhanced electrochemical performance. • Li/SCE/ LiFePO 4 full cell shows an excellent long-term cycling stability. NASICON-type Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP), with excellent air stability, a wide electrochemical window and low cost, is an attractive electrolyte for lithium-ion batteries (LIBs). However, its low electrical conductivity and poor interface contact impede its practical applications. Herein, LATP was doped with Sc and B elements, and the properties of the resultant LATP-based solid electrolytes were thoroughly studied. The structural characterization suggests that doping of Sc and B densifies the electrolyte structure, enlarges the lattice, and reduces grain boundaries. The optimized Li 1.3 Al 0.24 Sc 0.03 B 0.03 Ti 1.7 (PO 4 ) 3 (LASBTP003) achieves a high ionic conductivity of 8.82 × 10 −4  S/cm, equivalent to 4-fold that of pure LATP. The composition of LASBTP003 electrolyte with PVDF-HFP and SN results in PVDF-HFP-LITFSI-SN-LASBTP003 solid composite electrolyte with enhanced ionic conductivity of 8.89 × 10 −5  S/cm, attributed to the reduced PVDF-HFP crystallization and established lithium-ion migration pathways at LASBTP003/PVDF-HFP interface. PVDF-HFP-LITFSI-SN-10LASBTP003 also displays a wide electrochemical window of 4.85 V and a high Li-ion transference number of 0.41. The Li/ PVDF-HFP-LITFSI-SN-10LASBTP003/Li symmetric battery delivers a long cycling of 1800 h under a current density of 0.1 mA/cm 2 . Moreover, LiFePO 4 /PVDF-HFP-LITFSI-SN-10LASBTP003/Li full cell delivers a long-term cycling stability, with a capacity retention of 86.92% after 1000 cycles at 0.5C. Overall, the proposed PVDF-HFP-LITFSI-SN-10LASBTP003 has great potential for LIB applications. Download: Download high-res image (195KB) Download: Download full-size image