Defects, dopants and lithium incorporation in LiPON electrolyte

Abstract

Lithium phosphorus oxy-nitride (LiPON) is a candidate solid electrolyte material for potential use in rechargeable lithium-ion batteries. The use of density functional theory simulations has allowed us to gain atomic-scale insight into the defect properties, solution of dopants and incorporation of lithium in LiPON. The Li2O Schottky is the most favourable disorder process in this material ensuring the formation of Li and O vacancies which are in turn required for vacancy mediated self-diffusion. The Na, As and S are the promising isovalent dopants that can be substituted on the Li, P and O sites respectively. The doping of Mg on the Li site leads to the formation of Li vacancies in LiPON. The promising dopant on the P site to create Li interstitials and oxygen vacancies is the Ge. The stability of the crystal structure upon Li incorporation (up to four Li) was considered. The incorporation confirmed the formation of Li+ ions and expanded the volume of the lattice. Incorporation of multiple Li atoms is more favourable than a single Li incorporation. The band gap of this material decreases upon of Li incorporation without changing its insulating character. © 2021 Elsevier B.V.