Formation Mechanism of Amorphous Li4GeO4 Nanoparticles Synthesized by Induction Thermal Plasma for All-Solid-State Batteries

Induction thermal plasma as an advanced synthesis methodfor amorphousnanoparticles attracts a lot of attention. Amorphous Li4GeO4 nanoparticles were synthesized by induction thermalplasma with different Li/Ge molar ratios and quenching gas flow rates.Transmission electron microscopy, X-ray diffraction, and Raman spectroscopywere conducted to understand the product morphology and chemical composition.The formation mechanism was investigated according to experimentalresults and thermodynamic analysis. The topological order of preparednanoparticles was discussed in the short range and intermediate rangebased on O-Ge-O and Ge-O-Ge angle distributions,respectively. An enhanced amorphous degree of Li4GeO4 and a fraction of high-temperature-phase gamma-Li4GeO4 were obtained in high Ge content and quenching rateconditions. The amorphous Li4GeO4 degree achievedaround 65% with 10 L/min quenching gas injection. However, excessiveGe content and quenching rate also result in byproduct Li2GeO3 formation. The above results indicate that amorphousLi(4)GeO(4) nanoparticles can be efficiently synthesizedby induction thermal plasma with an appropriate Li/Ge molar ratioand quenching rate.