In the future, it can be expected that homogeneous nanomaterials will slowly give way to the development of non-planar architectures, at both the materials and system levels, as it has already been demonstrated for carbon5556. Nanomaterials will serve as building blocks, which assemble into hierarchical 3D architectures. This structure will improve electron and ion accessibility to redox-active sites, thus enabling fast electrochemical reactions (Fig. 4d, bottom) without introducing excessive porosity that may reduce the volumetric energy density. 3D electrode architectures maximize the number of active sites accessible to ions during charge/discharge and lead to high energy density without compromising power density. Such structures could also incorporate highly conductive components and eliminate the need for current collectors, thereby minimizing volume/mass of inactive materials in the EES device.