Next-Generation Li-ion Batteries Made with Spatial Atomic Layer Deposition as an Enabling Technology

Abstract

Today, Li-ion batteries are key devices in energy storage, with a wide set of applications ranging from mW to kW, such as portable electronics devices, electric vehicles and grid-storage. Typically, high energy density anodes such as Si or Li, combined with Ni- or Li-rich cathodes 1,2 are necessary to obtain the targeted gravimetric energy density (>350 Wh/kg). However, several high-potential redox-chemistries can lead to serious safety and degradation issues during charge-discharge cycling due to oxidative and reductive instabilities 3, that often occur at the electrode-electrolyte interfaces 4. Therefore, for every Li-ion battery chemistry the optimization of these interfaces with chemo-mechanically stable and Li-ion conductive passivation layers is essential in mitigating the non-compatibility of the individual cell components. These interface stabilizing layers can be incorporated either in-situ by using electrolyte additives or ex-situ by chemical and physical methods.One popular option here is offered by atomic layer deposition (ALD) which is today’s technology of choice to achieve films with superior quality and 3D-conformality with atomic-scale thickness precision. However, conventional vacuum-based temporal ALD is not compatible with industrial high-throughput roll-to-roll battery electrode production. Here, the technique of large-area atmospheric-pressure spatial-ALD (s-ALD) as pioneered by TNO-Holst Centre over a decade ago can offer prime solutions for various applications including thin-film batteries 5. This technique opens up a wide range of cost-effective applications based on materials like metal oxides, nitrides, sulfides, oxysulfides as well as hybrid organic-inorganic material combinations.In this presentation, we will discuss the growth of several s-ALD films made from Al2O3, TiO2, and ZnO which have been specifically optimized for dendritic Li-growth suppression, interface stabilization, and cathode degradation protection. Next, we will discuss some recent results on the up-scalable s-ALD growth of thin LiPON electrolyte films with a high Li-ion conductivity of >10-7 S/cm, low electronic conductivity of <10-12 S/cm, and high stability against anodic Li-metal during cycling. This electrolyte is also essential in the development of protective layers in liquid and polymer electrolyte-based Li-ion batteries, and in thin-film solid-state batteries with ultra-thin electrolyte layers and planar and 3D topologies. REFERENCES S. Myung et al., ACS Energy Lett. 2, 196–223 (2017).G. Assat and J. M. Tarascon, Nat Energy 3, 373–386 (2018).H. Ryu et al., Chem. Mater. 3 (30), 1155-1163 (2018).D. Aurbach et al., Solid State Ionics 148, 405–416 (2002).P. Poodt et al., J. Vac. Sci. and Technol. A 30, 010802 (2012).