Investigation of the solid-state electrolyte/cathode LiPON/LiCoO2 interface by photoelectron spectroscopy

Abstract

The electronic structure of a solid electrolyte/ solid electrode interface (SESEI) of an all-solid-state thin film battery was investigated. The thin film battery consisted of a LiPON solid electrolyte and a LiCoO 2 cathode. The lithium phosphorus oxynitride (LiPON) electrolyte was RF sputtered in a step-by-step procedure onto the cathode and investigated by photoelectron X-rayinduced spectroscopy after each deposition step. An intermediate layer was found-composed of some new species-that differs in its chemical composition from the cathode as well as the LiPON solid electrolyte material and changes with growing layer thickness. In contrast, the electronic structure of the underlying cathode material remained predominantly unchanged.

Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches

“…Such experiments demonstrate for the LiCoO 2 /LiPON interface [51] that the chemical structure of LiPON is significantly different from inside the film reflected in the changing ratios Ob/Od and Nt/Nd during deposition (Fig. 26), indicating that during growth the electrolyte adapts to the low lithium chemical potential (i.e.…”

“…For the direct study of interfaces between electrode and electrolyte, interface analysis by deposition of the solid electrolyte onto cathode films with intermediate analysis [51,52] can be performed. In principle also the reverse deposition sequence is possible.…”

“…Until now, however, the realization of such 3-D structured thin film cells is impeded by the lack of conformal, chemical vapour depositionbased processes, especially for the electrolyte. Only recently, first Reprinted from [51] with kind permission of Springer Science and Business Media.…”

Interface reactions between LiPON and lithium studied by in-situ X-ray photoemission

“…The exposure of intercalation electrodes to lithium in UHV and the analysis by XPS is common in surface science [14,15] but no similar experiments with solid electrolytes are reported in literature. Recently Jacke et al [16] studied the interface between the cathode material LiCoO 2 and LiPON using a similar approach. Additionally Song et al [17] constructed an energy band alignment of the interface LiCoO 2 and LiPON from in-situ XPS measurements.…”

Insight Into the Formation of Lithium Alloys in All-Solid-State Thin Film Lithium Batteries

“…A LiPON electrolyte (Bates et al, 1992) was chosen as it is an amorphous solid-state electrolyte for lithium ion batteries that induces little-to-no scattering. This electrolyte offers high ionic conductivity and chemical stability against metallic lithium, which has led to its reported application in several solid-state LIB systems (Dudney, 2005;Jacke et al, 2010;Senevirathne et al, 2013). The thickness of substrate and encapsulation layers can contribute to a reduction in cell performance.…”