(622f) Application of in-Situ x-Ray Absorption Spectroscopy for Next-Generation Batteries

Application of in-situ x-ray absorption spectroscopy for
next-generation batteries

Mohammad N. Banis^(1,2), Xia Li⁽²⁾, Tom Regier⁽³⁾, Yongfeng Hu⁽³⁾,
Tsun K. Sham^(1,2), Xueliang Sun⁽²⁾

1. Soochow-Western Centre for Synchrotron
Radiation Research, Western University, London Ontario, Canada

2. Western University, London, Ontario,
Canada

3. Canadian Light Source, Saskatoon, Saskatchewan, Canada

mohammad.norouzi.b@gmail.com

The
fast pace growth of portable electronics and commercialization of electric
vehicles has increased the demand for low cost, high energy density, durable
and safer energy storage systems. This has attracted considerable research on
developing and improving various types of batteries, including
 Li/Na ion, Li-S and Li/Na-air
batteries. However, changes in the structure and chemistry of these systems
with the goal of improving their performance, requires a better understanding
of the underlaying processes during their operation. Furthermore, continuous
monitoring of state of health of batteries during operation is essential for
illuminating the degradation mechanisms and formulating methods to address their
durability issue. Thus, effective in-situ characterization techniques are
required to achieve these goals.

In the past few
years we have employed ex/in-situ X-ray absorption spectroscopy (XAS) methods
to study the cathode and anodes of Li ion, Li-S and Na-O₂ batteries
during their operation [1-3]. As an example, to promote safer high temperature
Li-S batteries using carbonate-based electrolyte, we have investigated the
reaction processes involved in their cathode electrode in detail. Using in-situ
XAS studies we have illustrated the irreversible reactions occurring at the
cathode with the application of carbonate electrolyte. Subsequently, we have
demonstrated the role of molecular deposited (MLD) alucone
coatings as a viable option to address the challenges in carbonate-based Li-S batteries
[1].

For metal - air batteries,
we have developed a Na-O₂ cell for in-situ soft XAS measurements
(compatible with high vacuum conditions), to investigate the
formation/decomposition of discharge products during cycling and study their
stability in the cell environment. We have tracked the formation and
decomposition of discharge products in a working Na-O₂ cell by
monitoring the O K-edge XAS spectrum at the positive electrode of the cell. The
results indicated reversible formation and decomposition of irregular
structures, and conformal film-like NaO₂ on the surface of Au air
electrode during the discharge/charge cycles, respectively. Using in-situ soft
XAS (mapping) measurements in conjunction with electrochemical characterization
and ex-situ electron microscopy, we have shown a progressive degradation
reaction occurs at the products/electrolyte interface. We have illustrated that
in-situ soft XAS at the O K-edge, provides the appropriate selectivity and
sensitivity required for the analytical tacking of the products in Na-O₂
cells.

These researches
demonstrate the crucial role in-situ XAS studies play in development and
improvement of energy systems.

1.    
X. Li, A.
Lushington, Q. Sun, W. Xiao, J. Liu, B. Wang, Y. Ye, K. Nie,
Y. Hu, Q. Xiao, R. Li, J. Guo, T. K. Sham, X. Sun, Nano Letters, 2016, 16, 3545

2.    
H.
Yadegari, M. Banis, A. Lushington, Q. Sun, R. Li, T. K. Sham, X. Sun, Energy
Environ. Sci., 2017, 10, 286

3.    
H.
Yadegari, C. Franko, M. Banis, Q. Sun, R. Li, G. Goward,
X. Sun, J. Phys. Chem. Lett., 2017, 5, 4794