Oxygen vacancy in LiTiPO5 and LiTi2(PO4)3: A first-principles study

The structures of LiTiPO5 and LiTi2(PO4)3, as well as the possibility of oxygen vacancies formation in the systems are studied by first-principles calculations. It is found that oxygen vacancies can be formed in LiTiPO5 and LiTi2(PO4)3 under oxygen poor condition. The formation of oxygen vacancies introduce a defect band within their band gaps, which is expected to improve the electronic conductivity of LiTiPO5 and LiTi2(PO4)3 significantly. Meanwhile, a great concentration of oxygen vacancies may increase the discharge voltage of LiTiPO5 and LiTi2(PO4)3.