Solid state energy storage devices are typically realized as planar structures fabricated by thin film techniques, though new options are on the horizon including 3D configurations achieved by thin film or particle composite approaches. Here we focus on the former, recognizing that thin film methods offer precision control of nanostructure synthesis, particularly using physical vapor deposition (PVD) and atomic layer deposition (ALD). When combined with microfabrication for patterning to produce 3D scaffolds, these methods enable exploration of high performance 3D architectures of dense micro- and nano- scale solid state electrochemical structures. Interdigitated electrode structures are achieved by conformal ALD deposition of both electrode and solid electrolyte materials, leading to a fully conformal 3D solid state battery that demonstrates the benefits of 3D architectures. These synthesis processes and resulting structures also serve as valuable testbeds to study interface reactions, properties, and architectures, using a variety of characterization techniques including XPS/surface analysis, FIB cross-sections, ToF-SIMS, Kelvin probe microscopy, TEM/SEM, and others.
This work has been supported by Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award Number DESC0001160.