Ever been higher demands for energy storage systems that can exceed the energy density of current Li-ion battery encourage researchers to investigate new battery chemistries that are beyond the limitation of the current intercalation mechanism based battery chemistry.^1–3 Among many candidates for the beyond-intercalation batteries, Li-air battery, also known as Li-O₂ battery, got enormous research attention owing to their ultra-high theoretical gravimetric energy density of 3,458 Wh/kg.

Althogh high volumetric energy density is desired for transportation applications due to the space limitation in a vehicle, its volumetric energy density (Wh/L) with actual cell scale evaluation has been rarely discussed.⁴ It may be due to the theoretical maximum value, 2,040 Wh/L of Li-O₂ battery with lithium anode, is not much superior than Li-ion battery with LiCoO₂ cathode with carbon anode, 1,940 Wh/L.⁵

Here, we demonstrate the Li-O₂ battery cells perfuming 700 Wh/kg and 610 Wh/L of complete cell level gravimetric and volumetric energy density, respectively, by seamless integration of all the best performing components. To understand transport phenomena inside of the cell and predict maximum performances, specifically designed modeling and simulation was conducted by combining physics of oxygen gas flow into the GDL, dissolution of O₂ into the electrolyte, electrochemistry across the whole cell components, and dynamically changing carbon surfaces and porosity by Li₂O₂ formation.

References

1. Freunberger, S. A. True performance metrics in beyond-intercalation batteries. Nat. Energy 2, 17091 (2017).

2. Lu, J. et al. Aprotic and Aqueous Li–O2 Batteries. Chem. Rev. 114, 5611–5640 (2014).

3. Grande, L. et al. The Lithium/Air Battery: Still an Emerging System or a Practical Reality? Adv. Mater. 27, 784–800 (2015)

4. Gallagher, K. G. et al. Quantifying the promise of lithium-air batteries for electric vehicles. Energy Environ. Sci. 7, 1555–1563 (2014).

5. Lu, Y.-C. et al. Lithium-oxygen batteries: bridging mechanistic understanding and battery performance. Energy Environ. Sci. 6, 750–768 (2013).