| AVS 62nd International Symposium & Exhibition | |
| Energy Frontiers Focus Topic | Tuesday Sessions |
| Session EN+EM+NS+SE+SS+TF-TuA |
| Session: | Batteries and Supercapacitors |
| Presenter: | Alexander Kozen, University of Maryland, College Park |
| Authors: | A.C. Kozen, University of Maryland, College Park G.W. Rubloff, University of Maryland, College Park |
| Correspondent: | Click to Email |
Solid Li-based inorganic electrolytes offer profound advantages for energy storage in 3-D solid state batteries: (1) enhanced safety, since they are not flammable like organic liquid electrolytes; and (2) high power and energy density since use of the 3D geometry can maximize the volume of active material per unit area, while keeping the active layer thickness sufficiently small to allow for fast Li diffusion. The quality of thin solid electrolytes is currently a major obstacle to developing these solid state batteries, restricting electrolyte thickness to >100 nm to control electronic leakage, consequently slowing ion transport across the electrolyte and impeding 3-D nanostructure designs that offer high power and energy.
Furthermore, the ion-conducting, electron-insulating properties of solid electrolytes are promising for their use as protection layers on metal anodes (e.g., Li, Na, Mg) and on cathodes in proposed “beyond-Li-ion” battery configurations such as Li-NMC, Li-O2, and Li-S to prevent electrolyte breakdown.
Atomic layer deposition (ALD) is well suited to the challenge of solid electrolytes, providing ultrathin, high quality films with exceptional 3-D conformality on the nanoscale. We have developed a quaternary ALD processes for the solid electrolyte LiPON, exploiting in-operando spectroscopic ellipsometry and in-situ XPS surface analysis for process development. ALD LiPON has tunable morphology, and a nitrogen-dependent tunable ionic conductivity as high as 3.5x10-7 s/cm.
We explore the potential of ALD solid electrolytes for the fabrication of solid, 3D microbatteries, as we as the use of thin ALD solid electrolyte coatings on metal anodes to improve interfacial stability against organic electrolytes and thus prevent SEI formation. We demonstrate and quantify protection of lithium metal anodes with low ionic conductivity ALD Al2O3 coatings to prevent degradation reactions, and probe the surface chemistry and morphology of these anodes. Finally, we demonstrate that protection of Li metal anodes using ALD protection layers can improve the capacity of Li-S batteries by 60% by preventing anode corrosion by dissolved sulfur species in the electrolyte.
This work has implications beyond the passivation of lithium metal besides its focus and greatest impact on the Li-S battery system, as ALD protection layers could also be applied to other promising metal anode battery systems such as Mg and Na, and other beyond Li-ion technologies such as Li-NMC or- Li-Air where similar reactivity issues prevent adoption.