Ionic Conductivity and Cycling Performance in PEO Polymer Electrolyte Enhanced by Non-Milled In Situ Nano-LLZO Powders

HighLi(+) conductivity, good interfacial compatibility,and nano-scale particle size have always been essential conditionsfor selecting inorganic fillers in high-performance composite solidelectrolytes. In this study, non-milled in situ LLZO fillers withnanosize was synthesized via the sol-gel method by rapid heatingsintering, which resulted in more surface defects and fewer impuritiesin LLZO. Compared with milled LLZO fillers, these non-milled LLZOfillers with more surface defects and fewer impurities can effectivelyreduce the crystallinity of PEO and agglomeration in PEO, which canform composite electrolytes with high Li+ conductivity.Most importantly, the discharge capacity of the 7.5% non-milled LLZO-PEO-basedLiFePO(4)/Li battery is about 135.5 mA h g(-1) at 1C and 60 & DEG;C. After 100 cycles, the discharge specific capacityremains at 99%. It is worth noting that nano-sized non-milled LLZOwill improve the discharge capacity of LiFePO4/Li batteriesto 122.1 mA h g(-1) at 0.2C and 30 & DEG;C.

Automated summary

High Li+ conductivity, good interfacial compatibility, and nano-scale particle size are important factors in selecting inorganic fillers for high-performance composite solid electrolytes. In this study, non-milled in situ LLZO fillers were synthesized with nanosize via the sol-gel method, resulting in more surface defects and fewer impurities in LLZO. These fillers effectively reduce the crystallinity of PEO and agglomeration in PEO, leading to composite electrolytes with high Li+ conductivity. Notably, the non-milled LLZO-PEO-based LiFePO4/Li battery exhibits a discharge capacity of about 135.5 mA h g(-1) at 1C and 60°C, with a 99% discharge specific capacity remaining after 100 cycles. Furthermore, nano-sized non-milled LLZO improves the discharge capacity of LiFePO4/Li batteries to 122.1 mA h g(-1) at 0.2C and 30°C.