Evidence of a Thermal Diffusivity Gap in Sintered Li-Co-Sb-O Solid Solutions

Area of Science:

• Materials Science
• Solid-State Chemistry
• Thermal Physics

Background:

• Ternary oxides are crucial in advanced materials.
• Understanding thermal transport in solid solutions is key for thermal management applications.
• Previous studies have not fully explored the relationship between composition, sintering temperature, and thermal properties in this specific system.

Purpose of the Study:

• To investigate the thermal properties of Li₃ Co_7-4 Sb₂₊ O₁₂ solid solutions across varying concentrations (0 ≤ x ≤ 0.7).
• To determine the influence of different sintering temperatures (1100-1250 °C) on these thermal properties.
• To elucidate the impact of compositional changes (Li⁺, Sb⁵⁺, Co²⁺) on thermal diffusivity and conductivity.

Main Methods:

• Synthesis of Li₃ Co_7-4 Sb₂₊ O₁₂ solid solutions at four distinct sintering temperatures.
• Characterization of thermal properties, focusing on thermal diffusivity and thermal conductivity.
• Analysis of the relationship between sintering temperature, chemical composition, and observed thermal phenomena.

Main Results:

• A significant thermal diffusivity gap was identified, particularly at lower concentrations (low x) and around a threshold sintering temperature of 1150 °C.
• This diffusivity gap is attributed to an increased contact area between adjacent grains.
• The observed effect on thermal conductivity was less pronounced compared to thermal diffusivity.
• A new theoretical framework for heat diffusion in solids was proposed, emphasizing the role of thermal diffusivity in transient heat conduction.

Conclusions:

• Sintering temperature plays a critical role in determining the thermal diffusivity of Li₃ Co_7-4 Sb₂₊ O₁₂ solid solutions.
• Compositional variations and grain boundary effects significantly influence thermal transport mechanisms.
• The presented heat diffusion framework offers new insights into transient heat conduction phenomena in solids.