Experimental routes to in situ characterization of the electronic structure and chemical composition of cathode materials for lithium ion batteries during lithium intercalation and deintercalation using photoelectron spectroscopy and related techniques

Abstract

Three different experimental routes to in situ characterization of electronic structure and chemical composition of thin film cathode surfaces used in lithium ion batteries are presented. The focus is laid on changes in electronic structure and chemical composition during lithium intercalation and deintercalation studied by photoelectron spectroscopy and related techniques. At first, results are shown obtained from spontaneous intercalation into amorphous or polycrystalline V 2 O 5 thin films after lithium deposition. Although this technique is simple and clean, it is nonreversible and only applicable to the first lithium intercalation cycle into the cathode only to be applied to host materials stable in the delithiated stage. For other cathode materials, as LiCoO 2 , a real electrochemical setup has to be used. In our second approach, the experiments are performed in a specially designed electrochemical cell directly connected to the vacuum system. First experimental results of RF magnetron sputtered V 2 O 5 and LiCoO 2 thin film cathodes are presented. In the third approach, an all solid-state microbattery cell must be prepared inside the vacuum chamber, which allows electrochemical processing and characterization by photoelectron spectroscopy in real time. We will present our status and experimental difficulties in preparing such cells.

In Situ Ambient Pressure X-ray Photoelectron Spectroscopy Studies of Lithium-Oxygen Redox Reactions

“…S3), which is due to the increasing lithium content in Li x V 2 O 5 as expected from Li ion migration from the LLTO to Li x V 2 O 5 with decreasing applied voltage from 1.8 to 0 V cell . The Li 1s peak centered at 55.5 eV could be assigned to surface carbonate species such as Li 2 CO 3 (55.5 eV)25 that was formed upon air exposure on Li x V 2 O 5 and LiPON, Li x V 2 O 5 (55.7–55.9 eV)26 and partially to LiPON (56.0 eV)27. The increasing Li 1s intensity was accompanied with the broadening and gradual shift of the V 2p peak to lower binding energy, indicating lowered valence state of vanadium ions upon discharge.…”

Temperature dependent phosphorous oxynitride growth for all-solid-state batteries

“…The XPS system used was a Physical Electronics PHI-5700, with monochromatic Al K ␣ radiation with the energy of 1486.6 eV and a spectral resolution of 400 meV [25]. Survey scans were taken between 0 and 1400 eV, high resolution spectra were taken in the O1s, N1s, P2p and Li1s regions, no carbon was detected on the sample surface.…”

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

“…To analyze the electronic structure of cathode materials as a function of the lithiation state, two approaches can be followed to adjust the state-of-charge [44], depending on the material: intercalation from the gas phase (for materials prepared in the delithiated state only) [45] and electrochemical (de)lithiation [42,46]. In the first approach, the thin film cathode (e.g.…”