CA-CE-TI-MN-O-BASED PEROVSKITES FOR TWO-STEP SOLAR THERMOCHEMICAL HYDROGEN PRODUCTION CYCLES THE PROJECT AIMS TO MAXIMIZE THE EFFICIENCY OF TWO-STEP SOLAR THERMOCHEMICAL H2 PRODUCTION (STCH) WITH CA-CE-TI-MN (CCTM) OXIDE PEROVSKITES BY COMPOSITION ENGINEERING TO ACHIEVE SUCH HIGH EFFICIENCY THAT WE CAN REALISTICALLY TARGET THE LOWEST COST POSSIBLE FOR HYDROGEN PRODUCTION. SPECIFICALLY, WE WILL (OBJECTIVES IN BOLD, EXPECTED OUTCOMES IN ITALICS) 1.CONSTRUCT MULTI-SCALE COMPUTATIONAL METHODS, WHICH WILL RESULT IN A PYTHON PACKAGE PYTCH (PYTHON PACKAGE FOR THERMOCHEMICAL H2) THAT LEVERAGES DENSITY FUNCTIONAL THEORY (DFT) BASED MACHINE LEARNING, THERMODYNAMIC, AND SYSTEM EFFICIENCY MODELS TO IDENTIFY EFFICIENCY-MAXIMIZING COMPOSITIONS AND CONDITIONS; 2.OPTIMIZE CCTM, WHICH WILL RESULT IN THE COMPOSITION OF CCTM THAT MAXIMIZES THE H2 PRODUCTION EFFICIENCY AND SURPASSES THE ¿D/3 (I.E., PER ATOM) OF CERIA WHEN REDUCED AT 1773 K AND 10 PA AND RE-OXIDATION AT 1123 K AND 1000:1 STEAM:H2 AT A LOWER TEMPERATURE AND HIGHER PARTIAL PRESSURE, NAMELY 1623 K, 100 PA, AND SAME RE-OXIDIZING CONDITIONS. IT IS IMPORTANT TO CLARIFY THAT WE ARE USING ¿D/N AS A PERFORMANCE METRIC, WHERE N IS DEPENDENT ON THE MATERIAL (FOR EXAMPLE, N=3 FOR CERIA, AND N=5 FOR A PEROVSKITE), INSTEAD OF THE SOLAR-TO-HYDROGEN CONVERSION EFFICIENCY. THIS IS BECAUSE THE SOLAR-TO-HYDROGEN CONVERSION EFFICIENCY IS INFLUENCED BY MULTIPLE VARIABLES, MOST OF WHICH ARE INDEPENDENT OF THE MATERIAL. THE ¿D/N METRIC IS CRUCIAL AS IT DETERMINES THE NUMBER OF ATOMS THAT HAVE TO BE HEATED EACH CYCLE AND IS A CRITICAL DETERMINANT OF EFFICIENCY. THIS IS PARTICULARLY SIGNIFICANT FOR HEAT RECOVERY AND THE HEAT REQUIRED FOR THE PROCESS, WHICH ARE STRONGLY CONNECTED TO ¿D/N AND ARE AMONG THE KEY FACTORS THAT CONTRIBUTE TO OVERALL EFFICIENCY; 3.ENGINEER CCTM VIA CATION SUBSTITUTION, WHICH WILL RESULT IN A SENARY (SIX-ELEMENT) COMPOSITION THAT FURTHER INCREASES THE H2 PRODUCTION RATE; 4.ANALYZE THE TECHNOECONOMICS OF TWO-STEP STCH WITH CCTM, TO DETERMINE COST DRIVERS FOR HYDROGEN PRODUCTION; AND 5.DEMONSTRATE PROOF OF CONCEPT OF THE TWO-STEP STCH WITH CCTM, WITH THE LABYRINTH REACTOR (LR) DESIGNED TO PRODUCE FOR >1 G/H H2 IN A SOLAR SIMULATOR. AS AN AMBITIOUS STRETCH GOAL, WE WILL STRIVE TO PAVE THE WAY TOWARDS MAKING $2/KG H2 WITHIN STRIKING DISTANCE.