(670c) An Air Breathing Lithium-Oxygen Battery

Authors: 
Sayahpour, B., University of Illinois at Chicago
Asadi, M., University of Illinois at Chicago
Abbasi, P., University of Illinois at Chicago
Curtiss, L. A., Argonne National Laboratory
Salehi-Khojin, A., University of Illinois at Chicago
The Li-air batteries possess the highest theoretical energy density compared to any other battery chemistries1,2. However, these batteries suffer from a poor cycle life in the presence of real air components such as nitrogen, oxygen, carbon dioxide and moisture because of anode degradation, electrolyte instability, and slow kinetics of oxygen reduction and evolution in the air cathode3–5.

Here, we report a new Li-Air battery system working with the actual air components (N2, O2, CO2 and H2O) with very high cycle life and energy efficiency that can work up to 550 continues cycles with the capacity of 500 mAh/g. This Li-Air battery benefits from a protected Li-anode, an air cathode based on MoS2 catalyst and a mixture electrolyte. Different characterizations including differential electrochemical mass spectroscopy (DEMS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy on the cathode reveal that the only discharge product in our system is lithium peroxide (Li2O2) without any evidence of side products e.g., lithium hydroxide (LiOH) and lithium carbonate (Li2CO3). Nuclear magnetic resonance (NMR) results also show the stability of the electrolyte after 550 cycles. DFT calculations reveal that the combination of MoS2 cathode and mixture electrolyte make the system kinetically favorable for Li2O2 formation hindering the formation of other possible products. The Li-air system studied here is a key step toward the development of next generation of lithium batteries with higher energy density.

References:

1. Aurbach, D., McCloskey, B. D., Nazar, L. F. & Bruce, P. G. Advances in understanding mechanisms underpinning lithium–air batteries. Nat. Energy 1,16128 (2016).

2. Bruce, P. G., Freunberger, S. A., Hardwick, L. J. & Tarascon, J.-M. Li–O2 and Li–S batteries with high energy storage. Nat. Mater. 11,19–29 (2011).

3. Ye, L. et al. Lithium-Air Batteries: Performance Interplays with Instability Factors. ChemElectroChem 2,312–323 (2015).

4. Asadi, M. et al. Cathode Based on Molybdenum Disulfide Nanoflakes for Lithium-Oxygen Batteries. ACS Nano 10,2167–75 (2016).

5. Geng, D. et al. From Lithium-Oxygen to Lithium-Air Batteries: Challenges and Opportunities. Adv. Energy Mater. 201502164, 1–14 (2016).