Phosphorus doped Li2FeSiO4 thin films prepared by magnetron sputtering as high-performance thin-film cathode materials

Polycrystalline Li2FeSiO4 2 FeSiO 4 (LFS) and Li2FePxSi1-xO4 2 FeP x Si 1-x O 4 (LFSP) thin film cathode materials tested in quasi-solid thinfilm Li-ion cells have been synthesized using radio frequency magnetron sputtering in combination with rapid thermal annealing. The thin films were characterized for their phase and morphology using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The charge transport properties and electrochemical performance of the films were evaluated through constant current charge-discharge tests, cyclic voltammetry, rate performance testing, electrochemical impedance spectroscopy (EIS), and galvanostatic intermittent titration technique (GITT). The research findings revealed that after the sputtering growth process, during rapid annealing at 850 degrees C, the as prepared amorphous Li2FeSiO4 2 FeSiO 4 thin film showed selective crystalline growth, while crystallized grains on the surface of Li 2 FeSi 0.95 P 0.05 O 4 thin films exhibited a fusion like and relatively regular distribution. The electronic conductivity and ionic conductivity of Li 2 FeSi 0.95 P 0.05 O 4 thin films were measured at 6.60 x 10-7S & sdot;cm-- 7 S & sdot; cm- 1 and 4.87 x 10-7S & sdot;cm-- 7 S & sdot; cm- 1 , respectively. The Li 2 FeSi 0.95 P 0.05 O 4 thin film displayed an initial discharge specific capacity of 224.05 mAh g- 1 at a rate of 0.1 C, with a capacity retention of 73.5 % after 100 cycles in half-cell structure. The assembled Li 2 FeSi 0.95 P 0.05 O 4 / Li1.3Al0.3Ti1.7(PO4)3/Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 /Li quasi-solid-state battery presented an initial discharge specific capacity of 195.62 mAh g- 1 fabrication and doping modification of poly-anion-type Li2FeSiO4 2 FeSiO 4 cathode thin film materials, thus aiding the progress of next-generation thin-film quasi-solid-state lithium-ion batteries. at 0.1 C, with a capacity retention of 55.03 % after 100 cycles. This study offers a valuable reference for the