Thermal transport in phase-stabilized lithium zirconate phosphates

Abstract

The thermal properties of yttrium-stabilized lithium zirconate phosphate [LZP: Li1+x+yYxZr2−x(PO4)3 with x = 0.15, −0.2 ≤ y ≤ 0.4 and with x = 0.0, y = 0.0] are presented over a wide temperature range from 30 to 973 K, elucidating the interplay between structural phase transformations and thermal properties in a solid state superionic conducting material. At room temperature, the thermal conductivity decreases by more than 75% as the stoichiometry is changed from lithium deficient to excess and increases with increasing temperature, indicative of defect-mediated transport in the spark plasma sintered materials. The phase transformations and their stabilities are examined by x-ray diffraction and differential scanning calorimetry and indicate that the Y3+ substitution of Zr4+ is effective in stabilizing the ionically conductive rhombohedral phase over the entire temperature range measured, the mechanism of which is found through ab initio theoretical calculations. These insights into thermal transport of LZP superionic conductors are valuable as they may be generally applicable for predicting material stability and thermal management in the ceramic electrolyte of future all-solid-state-battery devices.

Temperature- and vacancy-concentration-dependence of heat transport in Li3ClO from multi-method numerical simulations

“…Even though some models that account for the contribution of the diffusing ions to thermal transport were introduced in the past decades 10,11 , a thorough study of heat dissipation in Li 3 ClO-and in SSE in general-is still missing. At the best of our knowledge, there exists only one calculation of the thermal conductivity, κ, of Li 3 ClO, reporting κ = 22.49 W m −1 K −1 at ambient temperature, i.e., more than one order of magnitude larger than the standard value found in ceramic SSEs 8,9 . Nonetheless, this seemingly promising result is obtained via a rather crude approximation to the Peierls-Boltzmann transport equation (BTE), namely the Slack model, known since its development to have a satisfactory agreement with the experiments (i.e., within ±20%) only for exceedingly simple materials, such as the rare-gas solids, while it is in general poorer for other systems 12 .…”

Thermal properties and lattice anharmonicity of Li-ion conducting garnet solid electrolyte Li6.5La3Zr1.5Ta0.5O12

“…[4][5][6] The successful implementation of the energy storage and conversion technologies hinges not only on their electrochemical performance but also on their thermal properties, particularly thermal conductivity (k) and thermal expansion coefficient. [7][8][9][10] The thermal properties of solid electrolytes play a crucial role in determining the safety and reliability of energy storage and conversion devices. 11 Lithium plating, which leads to reduced capacity in lithium-ion batteries, is sensitive to temperature.…”

Temperature- and vacancy-concentration-dependence of heat transport in Li$_3$ClO from multi-method numerical simulations

“…At the best of our knowledge, there exists only one calculation of the thermal conductivity, κ, of Li 3 ClO, reporting κ = 22.49 W m −1 K −1 at ambient temperature, i.e., more than one order of magnitude larger than the standard value found in ceramic SSEs. 8,9 Nonetheless, this seemingly promising result is obtained via a rather crude approximation to the Peierls-Boltzmann transport equation (BTE), namely the Slack model, known since its development to have a satisfactory agreement with the experiments (i.e., within ±20%) only for exceedingly simple materials, such as the rare-gas solids, while it is in general poorer for other systems. 12 Furthermore, the Slack approximation totally neglects the effects of defects/vacancies and, just like any BTEbased model, it cannot handle the spurious contributions to heat transport induced by the diffusion of Li ions.…”