To meet the requirements of the Long Duration Storage Energy Earthshot, rechargeable batteries for grid leveling and other grid-related uses are needed. The rising cost of lithium (Li), however, limits the practicality of using Li-ion (Li⁺) batteries for this application. One well-considered option is to develop sodium-ion (Na⁺) batteries, as sodium (Na) is readily sourced in the US and significantly less expensive than Li. For lower cost Na to replace Li in batteries, however, methods are needed to accommodate the larger size of Na⁺ and overcome the detrimental effects of strain from Na⁺ insertion. The scientific mission of the Center for Strain Optimization for Renewable Energy (STORE) is to develop methods to mitigate and manage structure and volume change upon Na⁺ insertion in electrochemical energy storage materials. The development of such designed materials will lead to lower cost electrodes for sodium-ion battery based grid-level energy storage. The three research projects that comprise the STORE program all focus on developing insertions hosts that can work without degradation or unduly slow ion diffusion. The first design approach aims to use lower cost metal oxides with large, rigid channels that can reversibly accommodate large guests like Na⁺ with minimal structure change. Initial studies will emphasize the use of tunnel structured oxides of titanium on the anode side, and of iron and manganese on the cathode side. The second approach focuses on layered transition-metal insertion hosts, which can distort more freely upon Na⁺ insertion.  This effort is directed at understanding the poorly reversible glide transitions that frequently occur upon Na⁺ intercalation. The goal here is to develop structures and chemistries that can either suppress glide transitions or make them reversible. Two complementary strategies are planned: (i) design new host chemistries and electrode particle geometries that accommodate elastic deformations to facilitate reversible glide phase transformations; (ii) determine new material compositions that suppress glide transformations altogether. The third and final project takes a different approach to the challenge of large strains. This effort involves materials with amorphous intermediates that plastically deform to accommodate strains, thus mitigating structural degradation through accommodation of large strains, rather than through suppression. The STORE team is largely geographically localized in Southern California, and brings together unique experimental expertise in key areas, including novel materials synthesis (ranging from nanoscale to bulk materials), and multi-scale structural characterization (using operando transmission X-ray microscopy, transmission electron microscopy, and a range of X-ray scattering tools). Theoretical efforts, which combine machine-learning approaches with first-principles statistical mechanics simulations, can create predictive frameworks for modeling disordered materials. At the continuum scale, variational formulations, including phase-field models are coupled with understanding gained from first-principles simulations to provide insights into the interplay between local structure, fracture, and ion diffusion.