From protonation & Li-rich contamination to grain-boundary segregation: Evaluations of solvent-free vs. wet routes on preparing Li7La3Zr2O12 solid electrolyte

Production of Ta-Doped Li7La3Zr2O12 Solid Electrolyte with High Critical Current Density

“…On the other hand, the decomposition behavior of Ta5Li4&6 powders milled for prolonged 6 h (Figure S10) was similar to that of Ta5Li4&6 milled for 3 h (Figure b), where the 6 h powders delivered a bit more weight loss of approximately 2% than that of 3 h powders. This result indicated a deeper Li + /H + exchange and LiOH·H 2 O/Li 2 CO 3 contamination of 6 h powders than that of 3 h, which would hinder the densification of LLZO due to the decomposition-recrystallization procedure during high temperature sintering. ,, There was a balance between “particle sizes” and “H + exchange degree” in determining the optimum milling duration, which was 6 h in our work conducted at Shenzhen, China with high relative humidity (RH) of 70–90% (25–30 °C). The milling duration could be further prolonged in areas with low RH.…”

“…Surprisingly, these powders in cubic LLZO phase after calcination at a high temperature of 950 °C for 6 h delivered obvious weight loss at 200–300 °C (VI). This might originate from the following decompositions: H 2 O (absorbed) → H 2 O (g), CO 2 (absorbed) → CO 2 (g), Li 6.5– x H x La 3 Zr 1.5 Ta 0.5 O 12 → H 2 O (g) + Decompositions . During the cooling procedure, H 2 O and CO 2 in the ambient air reacted with the excessively strongly alkaline Li 2 O and surfaces of cubic LLZO particles to form chemically absorbed species .…”

“…Surprisingly, these powders in cubic LLZO phase after calcination at a high temperature of 950 °C for 6 h delivered obvious weight loss at 200−300 °C (VI). This might originate from the following decompositions: 44 During the cooling procedure, H 2 O and CO 2 in the ambient air reacted with the excessively strongly alkaline Li 2 O and surfaces of cubic LLZO particles to form chemically absorbed species. 45 After ball milling with isopropanol at 120 rpm for 3 h, the number of weight loss stages dramatically increased to five (Figure 4b), which originated from various decompositions: I: 20−60 °C, decomposes during the TG-DSC test, the weight loss contributed by excessive Li in Ta5Li6 is calculated to be only 1.2%.…”

“…This result indicated a deeper Li + /H + exchange and LiOH•H 2 O/Li 2 CO 3 contamination of 6 h powders than that of 3 h, which would hinder the densification of LLZO due to the decomposition-recrystallization procedure during high temperature sintering. 44,45,47 There was a balance between "particle sizes" and "H + exchange degree" in determining the The Y = 8 ceramic pellets were placed at the bottom of the MgO crucible on the coarse gravel (Nb doped LLZO). The Nb would diffuse into the lattice at the surface of the Ta-LLZO pellet and the colors of these X8 pellets were not uniform after sintering (Figure 8a).…”

H3PO4-Induced Nano-Li3PO4 Pre-reduction Layer to Address Instability between the Nb-Doped Li7La3Zr2O12 Electrolyte and Metallic Li Anode

“…As shown in Figure d, the γ(τ) at 10 –7 to 10 –6 s represented the grain and grain boundary response in Nb-LLZO. At room temperature, the characteristic relaxation times of the grain and grain boundary were so close to each other that the two distinctive relaxation times were difficult to discern . The peaks at 10 –1 to 10 0 s represented the Ag blocking or Li reversible electrodes.…”