Thermodynamics of native defects in Li2O: A first-principles study

The crystals are used in deuterium-tritium fusion reactors and batteries, and crystal defects can increase the electrical conductivity. Therefore, the stability of the native point defects in Li2O has been examined in the work while taking vibration entropy into account. By calculations, we can obtain the defect formation energies including vacancies (VO, VLi), interstitials (Oi, Lii) and antisites (OLi, LiO), and the relationship between native point defect formation energy in Li2O versus Fermi level EF, oxygen partial pressure and temperature. The results indicate that the majority of the donors and acceptors are deep defect transition levels. The stable states of the vacancy-type defects, interstitial-type defects, and antisite defects are the fully charged state except antisite defects OLi. It is possible to predict that the acceptor defects are more likely to form under low oxygen partial pressure and high temperature, whereas the donor defects are more likely to form under high oxygen partial pressure and low temperature. Our work is aimed to provide the growth conditions for effectively adjusting the main type of defects and provide insightful guidance for the production and application of lithium oxide.

Automated summary

The stability of native point defects in Li2O has been investigated taking into account the vibration entropy. The study found that crystal defects can increase the electrical conductivity. Through calculations, defect formation energies, such as vacancies, interstitials, and antisites, were obtained, along with the relationship between defect formation energy and Fermi level, oxygen partial pressure, and temperature. The results suggest that most donors and acceptors exist at deep defect transition levels. The study aims to provide insight for adjusting the main type of defects and guidance for the production and application of lithium oxide.