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Electrochemical properties and optical transmission of high Li + conducting LiSiPON electrolyte films
Author(s) -
Su Yurong,
Falgenhauer Jane,
Leichtweiß Thomas,
Geiß Matthias,
Lupó Christian,
Polity Angelika,
Zhou Shengqiang,
Obel Jaroslava,
Schlettwein Derck,
Janek Jürgen,
Meyer Bruno K.
Publication year - 2017
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600088
Subject(s) - materials science , ionic conductivity , x ray photoelectron spectroscopy , conductivity , silicon , silicon oxynitride , analytical chemistry (journal) , electrolyte , lithium (medication) , sputter deposition , ionic bonding , band gap , electrochemistry , sputtering , thin film , chemical engineering , ion , nanotechnology , electrode , optoelectronics , silicon nitride , chemistry , engineering , medicine , organic chemistry , chromatography , endocrinology
Lithium silicon phosphorus oxynitride (LiSiPON) thin films with different compositions have been prepared by RF magnetron sputtering in N 2 by using three targets x Li 2 SiO 3 · (1 − x ) Li 3 PO 4 with x = 0.1, 0.3, and 0.5. Compared with LiPON, the electrical properties of LiSiPON have been improved by introducing silicon. LiSiPON films deposited from the target 0.5Li 2 SiO 3 · 0.5Li 3 PO 4 yield the highest ionic conductivity of up to 9.7 × 10 −6 S cm −1 with an activation energy of only 0.41 eV. The main mechanism for increasing ionic conductivity is the enhancement of carrier mobility. By DC polarization measurements the electronic partial conductivity was found at least seven orders of magnitude smaller than the ionic conductivity. Linear voltammetry results showed that the LiSiPON films are electrochemically stable in contact with stainless steel in the voltage range of 0–6 V. The substitution of silicon for phosphorus in the film evidenced from X‐ray photoelectron spectroscopy analysis indicated silicon in the film will create more abundant cross‐linking structures Si–O–P and (P, Si)–N < (P, Si), hence created more Li + conducting paths which favored the higher mobility of lithium ions and larger ionic conductivity. The optical bandgap was found to decrease with increasing silicon content. We demonstrate that the prepared LiSiPON films with their larger ionic conductivity and low electronic conductivity may serve as an alternative to LiPON for applications in high energy density and high voltage lithium batteries.