Influence of the Li–Ge–P–S based solid electrolytes on NCA electrochemical performances in all-solid-state lithium batteries

The effect of solid electrolytes , i.e. Li 10 GeP 2 S 12 and Li 3.25 Ge 0.25 P 0.75 S 4 , on the rate and low temperature performances of LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) cathode in all solid state lithium batteries is investigated. The ionic conductivities for the synthesized Li 10 GeP 2 S 12 and Li 3.25 Ge 0.25 P 0.75 S 4 at room temperature (RT) are 8.27   ×   10 −   3 and 2.03   ×   10 −   3   S   cm −   1 , respectively. These solid electrolytes are demonstrated as electrolytes for all solid state lithium batteries containing NCA cathode for the first time. The results show that Li 10 GeP 2 S 12 based battery exhibits superior rate performance (72.3   mAh   g −   1 at 1   C, RT), cycling stability (capacity retention of 87.1% after 30   cycles at 0.1   C, RT) and low temperature performance (79.2   mAh   g −   1 at 0.1   C and −   10   °C), which can be ascribed to its higher ionic conductivity and lower interfacial resistance between Li 10 GeP 2 S 12 and NCA cathode. It is indicated that all solid state lithium batteries with NCA cathode and Li 10 GeP 2 S 12 solid electrolyte can realize its potential application in high power and low temperature conditions.