This document summarizes research on developing self-formed catalysts for oxygen evolution reaction through electrochemical lithiation/delithiation of layered materials. It presents the current challenges with expensive IrO2 and RuO2 catalysts. The research models lithium cobalt oxide to understand how lithiation/delithiation tunes the material's structure and reactivity. Uncertainty quantification and probabilistic Pourbaix diagrams are developed to predict surface coverage and stability. The methodology aims to identify new intercalation materials as cheaper, high-activity catalysts. Future work will apply the descriptor approach to other materials for electrochemical applications.

1. Self-Formed Catalysts Using
Electrochemical
(de)Lithiation for Oxygen
Evolution Reaction
Vaidish Sumariaa, Dilip Krishnamurthyb, Venkat Viswanathana,b
aDepartment of Chemical Engineering, Carnegie Mellon University
bDepartment of Mechanical Engineering, Carnegie Mellon University

2. 1
Introduction
• Solar Energy – Inexhaustible Natural resource
• Oxygen evolution reaction – Key process in enabling solar driven water
splitting.
PEMFC
SOFC

3. 2
Current Scenario
IrO2 and RuO2 – among the most active
catalysts
i. Material Scarcity
ii. High cost
Lee Y. et. al. J. Phys. Chem. Lett., 2012, 3 (3), pp Man I.C. et. al. ChemCatChem 2011, 3, 1159 –

4. Reaction Mechanism for Oxygen Evolution Reaction
2H2O l → O2 g + 4H+
+ 4e−
(ΔGrxn = 4.92 eV)
Associative mechanism
H2O (l) + *  OH* + H+ + e- (Δ𝐺1)
OH*  O* + H+ + e- (Δ𝐺2)
O* + H2O (l)  OOH* + H+ + e- (Δ𝐺3)
OOH*  * + O2 (g) + H+ + e- (Δ𝐺4)
3
Man I.C. et. al. ChemCatChem, 2011, 3, 1159 –
E H+
+ E e−
= −
kT
2
ln 10 × pH + −eU +
1
2
× E H2 g
Calculated using DFT
∆𝐺 = ∆𝐸 − 𝑇∆𝑆 + 𝑍𝑃𝐸

5. Potential Determining Steps
4
𝐺𝑂𝐸𝑅
= max[ ∆𝐺1
0
, ∆𝐺2
0
, ∆𝐺3
0
, ∆𝐺4
0
]
Potential determining step - last step to become
downhill in free energy as the potential
increased.
Scaling relation : Δ𝐸𝑂𝑂𝐻 = Δ𝐸𝑂𝐻 + 3.2 (𝑒𝑉)
𝐺𝑂𝐸𝑅
= max ∆𝐺2
𝑜
, ∆𝐺3
𝑜
= max[ ∆𝐺2 , 3.2- ∆𝐺2 ]
= max[ ∆𝐺3 , 3.2- ∆𝐺3 ]
Descriptors (∆𝐺2) or (∆𝐺3) can be used as the
single descriptor to predict limiting potential.

6. Tuning the Adsorption Characteristics
• Strain
5
Strasser P. et. Al., Nature Chemistry, 2010, 2, 454–460

7. Tuning the Adsorption Characteristics
6
• Changing the Electronic Structure
Stamenkovic V., Angewandte Chemie 118.18 (2006): 2963-2967.

8. (De)Intercalation –To tune Activity
2D Layered Materials – emerging family of materials with tunable properties
Wang H. et. al. Proc. Natl. Acad. Sci., (2013) 110(49) 19701- 7

9. (De)Intercalation – Tool to tune Activity
Lu Z. et. al. Nat. Commun., 5 (2014): 8

10. Criteria For Catalyst selection
“Cathodic materials”
Potentially suitable for Oxygen
Evolution
LCO , LMO , LFP , NMC, NMO, NCA
etc.
“Anodic materials”
Potentially suitable for Oxygen
Reduction
Graphene , MoS2 , h-BN , M-Se2 etc.
Stability
1. ∆𝐺𝑓𝑜𝑟𝑚 < 0
2. At the reaction potential, material
should:
• Not undergo phase transition
• Not undergo decomposition
9

11. Lattice Optimization
Optimizing the bulk lattice of LiCoO2 and understanding the
effect of (de)litiation on the materials lattice parameters
Lattice Optimization for
LiCoO2
c (DFT)
c
(Experimental)
Li0.25CoO2 14.23 14.2
Li0.50CoO2 14.66 14.4
Li0.75CoO2 14.37 14.3
LiCoO2 14.16 14.07
10
Amatucci, G. G. et. al. , J. Electrochem. Soc., 143.3 (1996): 1114-

12. Pourbaix Diagram (LiCoO2)
11
The free energy of a given surface
as a function of the potential can be
given as:
𝑈 = 𝑛 ∗ 𝜃 ∗ (Δ𝐺𝑟𝑥𝑛(𝑈 = 0) − 𝑈)
Where:
n = No. of electron involved
𝜃 = Coverage on the surface

13. Uncertainty Quantification using BEEF-vdW
12
Wellendorff, Jess, et al., Phys. Rev. B 85.23 (2012): 235149.

14. Probabilistic Pourbaix Diagram
13
Fraction on
Surface (%)
Clean 4.5
½ ML OH* 44.8
½ ML O* 50.7
Surface coverage prediction at
U=0

15. Activity Volcano
14

16. Conclusion
• Intercalation materials can be
the new direction to look for
cheaper and high activity
catalysts
• We develop a new
methodology to predict the
surface structure incorporating
the uncertainties obtained
using BEEF-vdW exchange
correlation.
• Develop a thorough
probabilistic Pourbaix
Diagram for the various
phases of LixCoO2 and
understand its effects on
activity.
• Develop a general descriptor
based approach to identify
new for intercalation
materials as catalysts for
various electrochemical
15
Future Work