Slow Lithium Transport in Metal Oxides on the Nanoscale

Abstract

This article reports on Li self-diffusion in lithium containing metal oxide compounds. Case studies on LiNbO 3 , Li 3 NbO 4 , LiTaO 3 , LiAlO 2 , and LiGaO 2 are presented. The focus is on slow diffusion processes on the nanometer scale investigated by macroscopic tracer methods (secondary ion mass spectrometry, neutron reflectometry) and microscopic methods (nuclear magnetic resonance spectroscopy, conductivity spectroscopy) in comparison. Special focus is on the influence of structural disorder on diffusion.

Facile Dry Coating Method of High‐Nickel Cathode Material by Nanostructured Fumed Alumina (Al2O3) Improving the Performance of Lithium‐Ion Batteries

“…This would significantly reduce the impedance of the otherwise insulating Al 2 O 3 coating layer because the lithium-ion conductivity of the liquid electrolyte is orders of magnitude higher than that of the metal oxides. [66][67][68][69] The porosity of our coating layer is also confirmed by BET measurements. For uncoated NMC, a BET area of %0.48 m 2 g À1 is measured, while the 1 wt% coated NMC has an increased BET surface of %1.50 m 2 g À1 .…”

Improved Cycling Performance of High‐Nickel NMC by Dry Powder Coating with Nanostructured Fumed Al2O3, TiO2, and ZrO2: A Comparison

“…Although lithium zirconate is attributed a significantly higher lithium ion conductivity than γ ‐lithium aluminate, [57,58] we observed the highest rate capability for the fumed Al 2 O 3 ‐coated NMC. However, as can be seen in Table 1, the BET surface area of the Al 2 O 3 ‐coated NMC (1.5 m 2 /g) is significantly higher than that of the ZrO 2 ‐coated sample (0.85 m 2 /g).…”

“…These results indicate a strong influence of the coating layer porosity, on the rate capability, which is a purely physical parameter. Assuming that the liquid electrolyte penetrates the porous coating layer, we suggest that the porosity of the coating has a significant influence on the lithium transport across the layer, besides the lithium diffusion coefficients of the coating materials themselves, since the diffusion coefficient of the liquid electrolyte is orders of magnitude higher than that of the lithiated metal oxides [57–61] . Therefore, the rate performance of ZrO 2 coated NMC cannot be optimized by varying the mass fraction of ZrO 2 such that it reaches the performance of Al 2 O 3 coated NMC.…”

“…Furthermore, it seems that the physical parameter of coating layer porosity, which is influenced by the BET surface area of the coating agent, has, besides the chemical composition of the coating material, a significant effect on the rate capability of the coated CAMs. Since lithium zirconate is attributed a significantly higher lithium ion conductivity than γ ‐lithium aluminate, [57,58] the lower rate performance of the ZrO 2 coated NMC arises from the inferior physical properties of the coating layer. It is very likely that, when these materials have the same porosity, the rate performance of ZrO 2 ‐coated NMC will be superior.…”

Mobility of Ions in Solids

“…Molife has been running since 2010 with Leibniz Universität Hannover as Speaker University and further groups from Technische Universität Berlin, Universität Bonn, Technische Universität Clausthal, Technische Universität Graz and Universität Oldenburg. It has comprised seven research subprojects entitled The 12 articles [4][5][6][7][8][9][10][11][12][13][14][15] collected in this issue are closely related to the above topics and mostly serve as final reports of the subprojects either in the form of reviews or as accompanying original publications. For a current list of molife publications over the years and other information from molife see www.for1277molife.…”