It is clear that current energy storage technologies are far from being ideal, and there is a need to redesign the energy storage device in terms of materials, architectures and electrolytes, among other features. To accomplish this goal requires more than just extensive parametric experimental studies. The challenge facing the experimental selection of materials and electrode architectures is that there are too many options available. For example, dozens of new 2D materials of potential use for electrode applications were discovered just in the past few years and many more are predicted to exist7778. There are also numerous parameters that can be varied (for example, pore size and shape, number of layers in 2D structures, composition and so on). The parameter space increases markedly when matching materials with appropriate electrolytes is considered. The question of how to select the right electrolyte for a particular material cannot be answered by just trying many thousands of salt solutions in every available solvent79. To promote future discoveries and achieve breakthroughs in energy storage there must be close integration of theory, modelling and simulation with synthesis and characterization over the full range of length and time scales—from atoms to microstructures to systems (Fig. 7a). Theory and modelling can provide guiding principles for selection of electrode materials, matching electrolytes and design of new architectures.