Sustainable Enhanced Sodium-Ion Storage at Subzero Temperature with LiF Integration

Though layered sodium oxide materialsare identifiedas promisingcathodes in sodium-ion batteries, biphasic P3/O3 depicts improvedelectrochemical performance and structural stability. Herein, a coexistentP3/O3 biphasic cathode material was synthesized with LiFintegration, verified with X-ray diffraction and Rietveld refinementanalysis. Furthermore, the presence of Li and F was deduced by inductivelycoupled plasma-optical emission spectrometry (ICP-OES) and energydispersive X-ray spectroscopy (EDS). The biphasic P3/O3 cathode displayedan excellent capacity retention of 85% after 100 cycles (0.2C/30 mAg(-1)) at room temperature and 94% at -20 & DEG;Cafter 100 cycles (0.1C/15 mA g(-1)) with superiorrate capability as compared to the pristine cathode. Furthermore,a full cell comprising a hard carbon anode and a biphasic cathodewith 1 M NaPF6 electrolyte displayed excellent cyclic stabilitiesat a wider temperature range of -20 to 50 & DEG;C (with theenergy density of 151.48 Wh kg(-1)) due to the enhancedstructural stability, alleviated Jahn-Teller distortions, andrapid Na+ kinetics facilitating Na+ motion atvarious temperatures in sodium-ion batteries. The detailed post-characterizationstudies revealed that the incorporation of LiF accounts for facileNa(+) kinetics, boosting the overall Na storage.

Automated summary

The synthesis and characterization of a coexistent P3/O3 biphasic cathode material with LiF integration is reported. The presence of Li and F was confirmed by spectroscopy techniques, and the biphasic cathode demonstrated improved capacity retention and rate capability compared to the pristine cathode.