Integration and Optimization of Novel Ion Conducting Solids (IONICS) The Integration and Optimization of Novel Ion Conducting Solids (IONICS) program seeks to enable transformational electrochemical cells by creating components built with solid ion conductors that have a wide range of desirable properties including low ionic area-specific resistance (ASR), high chemical and electrochemical stability, high selectivity, good mechanical properties, etc. through innovative approaches to overcome tradeoffs among coupled properties. It also seeks to develop and apply methods for processing of solid ion conductors and their integration into electrochemical devices. Components built with solid ion conductors, especially separators, have the potential to serve as enabling platforms, as demonstrated by the wide application of Yttria-Stabilized Zirconia (YSZ) ceramics and perfluorosulfonic acid (PFSA) polymers (e.g., Nafion®). The IONICS Program Categories focus on specific electrochemical cells with high impact for the energy sector whose commercial potential will be significantly enhanced with improved components built from solid ion conductors. The Program Categories include: 1. Lithium (Li) ion conductors that enable the cycling of Li metal without shorting 2. Selective and low-cost separators for batteries with liquid reactants (e.g., flow batteries) 3. Alkaline conductors with high chemical stability and conductivity 4. Other approaches that could achieve the IONICS Program Objectives. A key requirement of the IONICS program is the creation of manufacturable components with dimensions comparable to that used in a practical device, in order to ensure that technical challenges associated with large-area processing are addressed. The required area depends on the application, but is in the range of tens to one hundred square centimeters. A second key requirement is that the cost of materials and processing is sufficiently low to allow for the broad adoption necessary for significant energy impacts. Creating low-cost components built with solid ion conductors will require pushing the boundaries of processing methods, especially for inorganic materials. ARPA-E encourages the formation of teams that include the competence to address large-area fabrication and low-cost processing. ARPA-E expects that common technical themes will be present across the Program Categories. These themes may include, but are not limited to, polymer/inorganic composites, chemistries that realize high stability, processing methods for large-area and thin inorganic solid ion conductors, polymer and polymer composite morphology engineering, self-forming mechanisms, and others. ARPA-E expects that the realization of the aggressive targets of the IONICS program will require input from communities such as solid state ionics, polymers, ceramics, material mechanics (especially at interfaces), functional glasses, organic and inorganic chemistry, computational approaches across a range of length scales, and process engineering and scale up.