Planar two-dimensional (2D) solid-state lithium-ion batteries exhibit an undesirable energy versus power balance, which can be dramatically improved by the application of three-dimensional (3D) geometries. Current ceramics-based nanocomposites exhibit limited control of the distribution and orientation of the nanoparticles within the matrix material. However, the tailoring of functionalities by the strong coupling between the two phases and their interfaces, present in epitaxial 3D vertically aligned nanocomposites (VANs), show promising advantages over the conventional 2D planar multilayers. Although a range of epitaxial VANs have been studied in the last decade, lithium-based VANs toward battery applications have remained mostly unexplored. Interestingly, two recent studies by Qi et al. and Cunha et al. demonstrate the unique potential of lithium-based VANs toward the realization of 3D solid-state batteries with enhanced energy storage performance. In this article, we will discuss these promising results as an enhanced current collector within the cathode or as an integrated solid-state cathode-electrolyte composite. Furthermore, we will describe different design configurations that can be applied to realize self-assembled VAN-based complete 3D battery devices.