Radiation-induced thermal conductivity degradation in LiAlO2 and LiAl5O8 investigated by molecular dynamics

Abstract

Abstract Radiation damage in lithium ceramic materials can severely degrade thermal transport properties, limiting their performance in nuclear environments such as tritium-producing burnable absorber rods (TPBARs). This study compares the intrinsic thermal conductivity degradation in single crystals of LiAlO 2 and LiAl 5 O 8 due to radiation-induced point defects. LiAlO 2 shows a significant drop in thermal conductivity of up to 75% under increasing defect concentration and temperature, while LiAl 5 O 8 retains over 50% of its thermal conductivity, even at high defect levels and elevated temperatures. The greater resilience of LiAl 5 O 8 is attributed to its structural resilience, which suppresses defect generation and preserves phonon transport. Partial phonon density of states analysis reveals that Li and Al vacancies strongly suppress vibrational modes in LiAlO 2 , while LiAl 5 O 8 shows minimal change, supporting its superior radiation tolerance. These results suggest LiAl 5 O 8 to be a more durable candidate for high-temperature radiation environments.