Effects of Antisite Defects on Li Diffusion in LiFePO4 Revealed by Li Isotope Exchange

• DOI: 10.1021/acs.jpcc.7b02819
• Publication Date: 2017-05-16T21:41:57Z
• Authors: Hao Liu; Min-Ju Choe; Raul A. Enrique; Bernardo Orvañanos; Lina Zhou; Tao Liu; Katsuyo Thornton; Clare P. Grey
• Keywords: TRACER; Isotopes of lithium

Li–Fe antisite defects are commonly found in LiFePO4 particles and can impede or block Li diffusion the single-file channels. However, due to their low concentration (∼1%), effect of on has only been systematically investigated by theoretical approaches. In this work, exchange between solid (92.5% enriched with 6Li) liquid electrolyte solution (containing natural abundance Li, 7.6% 6Li 92.4% 7Li) was measured as a function time both ex situ solid-state nuclear magnetic resonance experiments. The experimental data reveal that dependence isotope cannot be modeled simple process must play role mobility ions particles. By performing kinetic Monte Carlo simulations explicitly consider defects, which allow cross over adjacent channels, we show observed tracer behavior explained presence channels paired defects. suggest across is slow (10–16 cm2 s–1) widespread examined, where ∼80% affected such