Influence of sintering additives on Li+ conductivity and electrochemical property of perovskite-type Li3/8Sr7/16Hf1/4Ta3/4O3

Cubic perovskite–type oxide Li 3/8 Sr 7/16 Hf 1/4 Ta 3/4 O 3 (LSHT) is a promising solid electrolyte material for next–generation Li–ion batteries such as all–solid–state Li batteries and Li–redox flow batteries due to its high room–temperature Li–ion conductivity and good chemical compatibility with commercial organic liquid electrolyte. High relative density is another important requirement for these applications. Here we investigate the influence of sintering additives (Li 3 BO 3 , Li 4 SiO 4 , LiF) on the density, the total Li–ion conductivity, the interfacial conductivity against commercial liquid electrolyte, and the cycling performance of the hybrid Li-ion cells. The results show that comparing with other additives, LSHT sintered with 2   wt% LiF shows the highest Li–ion conductivity (3.3   ×   10 −4   S   cm −1 ) and the smallest interfacial resistance (125   Ω cm 2 ) against organic electrolyte at room temperature; Li/LiFePO 4 batteries with LSHT pellets fired with 2   wt% LiF have the best cyclability and the highest coulombic efficiency (99.6   ±   0.04%) in 50 cycles.