Kyushu Synchrotron Light Research Center（ Form: No.5）

Experiment Report for Prefectural Beamline
Proposal no. : 1310119R
Beamline no.: BL12
Report date: 12/11/2013

Li-O 2 電 池 に お け る Li-O 2 電 気 化 学 反 応 生 成 物 の Ｘ 線 光 電 子 分 光 分 析
XPS analysis of lithium peroxide, carbonate and carboxylates forreference of Li-O 2 electrochemical reaction product for Li-O 2 battery
Hye Ryung Byon, Nadège Bonnet Mercier
Byon Initiative Research Unit, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama
351-0198 Japan※１Long term users of Advanced Research User Proposals are requested to submit thisreport corresponding to each research term (I), (II), or (III), specifying each researchterm at the end of the Report Title.

※2

Users of Non-proprietary proposals (Public User Proposal, Advanced Research User
Proposal with exception of both Trial Course and Industry-Academia Collaboration
Course, and Frontier Research User Proposal) are also requested to publish their resultsin the form of a refereed journal article or to submit their results in the form of aSAGA-LS Research Report refereed by SAGA-LS within two years from the end of thecurrent fiscal year．

１ ． Summary（ Note: Please include conclusions）
We obtained Li 1s and O 1s XPS spectra of Li 2 O 2 , Li 2 CO 3 , LiOH, LiCO 2 H, and LiCO 2 CH 3powders at BL12 of SAGA-LS, which would be used for reference data of real Li–O 2 reaction
products (proposal no. 1310118PT).

２．Purposeof experiment and background２．
The purpose of this project is to acquire Li 1s and O 1s X-ray photoelectron spectroscopy (XPS)
data of Li2O2, Li2CO3, LiOH, LiCO2H, and LiCO2CH3 powders. These XPS data will be used for thereference of Li–O2 reaction products, obtained in Li–O2 battery (proposal no. 1310118PT).
３．Experimental（Note:Description of sample，method of experiment and analysis, etc.）
３．
We prepared the following 5 powders (table).
No.

Sample name

PurityPreparation

1

Li2O299%

The powders completely dried in vacuum

2

Li2CO399%

oven were loaded on the XPS stage using

3

LiOH

98%

double-side

carbontapeinAr

4

LiCO2H

98%

5LiCO2CH399%

gas-filled glove box.

The powders were very thinly pasted on a double-side carbon tape in an Ar-filled glove box and directlytransferred to XPS chamber using a hermetic Ar-filled transfer vessel to avoid air exposure. The synchrotron
XPS measurements were performed using a photon energy of 650 eV and a base pressure of 10–8 Pa. The XPS
data were calibrated by the carbon-related peak obtained from the carbon tape.
４．Resultsand Discussions
４．
Since the insulating lithium-related powders generate the large charging effect, the XPS peaks were largely
shifted. These peaks were corrected by the calibration as referring to carbon (285.66 eV) acquired from thedouble-side carbon film underneath the powders. In addition, the small ejected photoelectron current (Is) fromthe insulating powder samples resulted in low signal to noise ratio of spectra peaks despite with many scanning
numbers. Figure 1 shows the resultant XPS spectra of O 1s and Li 1s binding energy (BE) regions. The Li2O2
has a symmetric O 1s peak at 532.5 eV and Li 1s peak at 55.9 eV. The LiOH has a similar O 1s peak to theLi2O2, i.e., 532.6 eV, whereas a Li 1s peak is slightly different, showing at 55.0 eV. The Li2CO3 has anasymmetric O 1s peak at 533.6 eV and a broad Li 1s peak at 56.7 eV. The lithium carboxylates (Li2CO2H andLi2CO2CH3) powders have very broad O 1s peaks in 532-534 eV and negligible Li 1s peak even more than 100times scan. The large charge effect hindered to obtain clear lithium carboxylates spectra using the XPS.

Figure 1. XPS spectra of (a) O 1s, (b) Li 1s Li2O2, LiOH, and Li2CO3, and (c) O 1s of LiCO2H and LiCO2CH3.

５．Future issues
Identifying chemical information of real Li–O2 reaction products (proposal no. 1310118PT) by referring tothese powder XPS data.

６．References
６．
None
７．Publications,patents（Note: Typical deliverables related to this proposal．）
７．
Publication: Rui Wen and Hye Ryung Byon, “In situ monitoring of the Li-O2 electrochemical reaction on
nanoporous gold using electrochemical AFM”, Chemical Communications, 2014, 50, 2628-2631.
８．Keywords（Note:2-3 words about samples and experimental methods．）
８．
Lithium-related compounds, Li-O2 battery, XPS

９．About
the publication of research results
９．
Please delete either item ① or item ② indicated below, according to a user’s choice of publications as
described in ※2. Also, please fill in an expected date of publication of a refereed journal article or an expected
date of submission of a SAGA-LS Research Report. For example, deadline of both publications
corresponding to the proposals performed in the fiscal 2013 is by the end of fiscal 2015 in both ① and ②.
 Publication of a refereed journal article
Submission of a manuscript for Research Report(the date of publication：(the date of submission：17/Jan/2014 ））