Pulsed Laser Deposition and Electrochemical Properties of LiFePO_4 Thin Films

摘要

Well-crystallized and homogeneous LiFePO_4 films, of the order of 300 nm thick, have been grown by pulsed laser deposition on Pt-capped Si substrates in a one-step process. Their intrinsic lithium insertion properties have been evaluated both in aqueous and nonaqueous electrolytes. The films show the electrochemical fingerprint characteristic of pure triphylite LiFePO_4, with, namely, equilibrium voltage at 3.42 V vs. Li~+/Li. While carbon-free, the kinetic of the insertion/deinsertion process in such films compared favorably with those of optimized carbon-coated LiFePO_4 powders. Furthermore, we demonstrate sensor responses of these thin-film LiFePO_4 electrodes toward the quantitative detection of Li~+ ions in aqueous solutions as long as their concentration ranges from 10~(-4) to 1 M.