How bulk sensitive is hard X-ray photoelectron spectroscopy: accounting for the cathode-electrolyte interface when addressing oxygen redox

DOI: 10.1021/acs.jpclett.0c00229

Authors: Zachary W. Lebens-Higgins (Binghamton University) , Hyeseung Chung (University of California San Diego) , Mateusz J. Zuba (Binghamton University) , Jatinkumar Rana (Binghamton University) , Yixuan Li (University of California San Diego) , Nicholas V. Faenza (Rutgers University) , Nathalie Pereira (Rutgers University) , Bryan D. Mccloskey (Lawrence Berkeley National Laboratory; University of California Berkeley) , Fanny Rodolakis (Argonne National Laboratory) , Wanli Yang (Advanced Light Source) , M. Stanley Whittingham (Binghamton University) , Glenn G. Amatucci (Rutgers University) , Ying Shirley Meng (University of California San Diego) , Tien-Lin Lee (Diamond Light Source) , Louis F. J. Piper (Binghamton University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry Letters

State: Published (Approved)
Published: February 2020
Diamond Proposal Number(s): 22250 , 22148

Abstract: Sensitivity to the `bulk' oxygen core orbital makes hard X-ray photoelectron spectroscopy (HAXPES) an appealing technique for studying oxygen redox candidates. Various studies have reported an additional O 1s peak (530-531 eV) at high voltages, which has been considered a direct signature of the bulk oxygen redox process. Here, we find the emergence of a 530.4 eV O 1s HAXPES peak for three model cathodes, Li2MnO3, Li-rich NMC, and NMC 442, that shows no clear link to expected oxygen redox. Instead, the 530.4 eV peak for these three systems is attributed to transition metal reduction and electrolyte decomposition in the near-surface region. Claims of oxygen redox relying on photoelectron spectroscopy must explicitly account for the surface sensitivity of this technique and the extent of the cathode degradation layer.

Journal Keywords: Redox reactions; Oxides; Electrodes; Oxygen; Transition metals

Subject Areas: Chemistry, Physics, Technique Development


Instruments: I09-Surface and Interface Structural Analysis

Other Facilities: ALS; Advanced Photon Source

Added On: 02/03/2020 14:04

Discipline Tags:

Surfaces Physics Physical Chemistry Technique Development - Chemistry Chemistry interfaces and thin films

Technical Tags:

Spectroscopy X-ray Photoelectron Spectroscopy (XPS) Hard X-ray Photoelectron Spectroscopy (HAXPES)