IGF::OT::IGF 1. INTRODUCTION BACKGROUND NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NASA GAME CHANGING TECHNOLOGY DEVELOPMENT PROGRAM IS DEVELOPING BATTERY TECHNOLOGY TO SUBSTANTIALLY IMPROVE THE PERFORMANCE OF SECONDARY RECHARGEABLE LITHIUM-ION CELLS TO MEET THE ENERGY STORAGE REQUIREMENTS OF HUMAN MISSIONS. FUTURE NASA MISSIONS REQUIRE ADVANCED BATTERIES THAT SAFELY PROVIDE SUBSTANTIALLY HIGHER SPECIFIC ENERGY AND ENERGY DENSITY THAN IS CURRENTLY AVAILABLE. THUS BEYOND LITHIUM-ION BATTERY CHEMISTRIES ARE PURSUED TO MEET THE HIGHER SPECIFIC ENERGY, PERFORMANCE AND SAFETY GOALS FOR FORESEEABLE HUMAN MISSIONS. ALTHOUGH THE EFFICACY OF THE UNDERLYING PROPOSED TECHNOLOGY WAS DEMONSTRATED SUCCESSFULLY IN THE CONTRACTOR, UNIVERSITY OF MARYLAND UMD, PRIOR WORK UNDER NASA PHASE I AND DOE ARPAE AND EERE CONTRACTS, THE CONTRACTOR WAS NOT ABLE TO OPTIMIZE THE CELL PARAMETERS, SUCH AS ELECTRODE PORE STRUCTURE AND FILLING, CATHODE TO ANODE CAPACITY RATIO, ETC, TO MAXIMIZE ENERGY DENSITY DUE TO PHASE I COST AND TIME LIMITATION. THE PROPOSAL OF GARNET ELECTROLYTE BASED SAFE, LITHIUM-SULFUR ENERGY STORAGE BY UMD TEAM HAS RECEIVED A PHASE II AWARD UNDER CATEGORY TWO, VERY HIGH SPECIFIC ENERGY DEVICE TO FIRST OPTIMIZE THE CELLS TO DEMONSTRATE ACHIEVABLE ENERGY DENSITY, THEN SCALE UP IN THE FULLFORMAT CELL AND BUILD MULTICELL STACKS FOR THE DEMONSTRATION AND FINALLY PROVIDE BATTERY PACK DESIGN TO MEET THE NASA ENERGY AND SAFETY REQUIREMENTS. 2. SCOPE OF WORK THE CONTRACTOR SHALL OPTIMIZE THE CELL PARAMETERS AND BUILD FULL FORMAT SOLID STATE LI S BATTERIES USING TRI-LAYER GARNET SOLID STATE ELECTROLYTE SSE STRUCTURE POROUS DENSE POROUS SCAFFOLD, WITH INFILTRATED LI INTO POROUS SSE AS ANODE, DENSE SSE AS SEPARATOR AND ELECTROLYTE, AND INFILTRATED S C INTO POROUS SSE AS CATHODE. ADDITIONALLY THE CONTRACTOR SHALL BUILD MULTICELL STACKS USING THOSE FULL FORMAT CELLS. THE TARGETED ENERGY DENSITY OF THE CELLS IS 540 WH KG WITH A LIFE OF 200 CYCLES WITH A 90 PERCENT DISCHARGE DEPTH AT ROOM TEMPERATURE. THE CONTRACTOR SHALL PROVIDE THE SPECIFICATIONS OF THE ANODE, CATHODE AND SOLID ELECTROLYTE CHEMISTRY IN THE CONSTRUCTION OF THE CELLS AND STACKS. THE CONTRACTOR SHALL PROVIDE DATA AND ANALYSIS FOR ADDRESSING THE OPERATIONAL SAFETY ISSUES. TWO STACKS WITH THE IDENTICAL DESIGN FOR THE ABOVE TEST CELLS SHALL BE PROVIDED FOR INDEPENDENT PERFORMANCE CHARACTERIZATION TESTING AT NASA GRC. THE CONTRACTOR SHALL ALSO PROVIDE A DESIGN FOR BATTERY STACKS TO MEET THE TOTAL ENERGY REQUIREMENTS OF NASA GAME CHANGING DEVELOPMENT PROGRAM. THE PROJECT IS CURRENTLY ESTIMATED AT A TECHNOLOGY READINESS LEVEL OF 3, AS DEFINED IN NASA NPR 7123.1B, AND SHALL END AT A TRL 4 AT THE END OF THE PHASE II EFFORT. DURING PHASE II, THE CONTRACTOR SHALL DEMONSTRATE THE FEASIBILITY OF FURTHER ADVANCING THE TRL DURING SUBSEQUENT PHASES OF DEVELOPMENT. 3. OBJECTIVES 3.1. FABRICATE FULL FORMAT, 10 CM X 10 CM, LI S BATTERIES USING TRI-LAYER GARNET ELECTROLYTES WITH SURFACE TREATMENT AND CONFORMAL CARBON COATING; 3.2. DEMONSTRATE AN ENERGY DENSITY OF 541 WH KG AND 1362 WH L WITH A CYCLING LIFE OF 200 WITH A 90 PERCENT DISCHARGE DEPTH AT C 10; 3.3. SUCCESSFULLY STACK AND PACKAGE 3 FULL FORMAT CELLS IN SERIES WITH ROBUST PERFORMANCE FROM 10 DEGREES C TO 30 DEGREES C; 3.4. DEVELOP BATTERY PACK DESIGN TO MEET THE TOTAL ENERGY REQUIREMENT OF THE NASA GAME CHANGING DEVELOPMENT PROGRAM. 4. TASKS THERE ARE NINE TASKS FOR THE PROPOSED WORK AS FOLLOWS. TASK 1. OPTIMIZATIONS OF POROUS DENSE POROUS TRILAYER GARNET ELECTROLYTE 1.1 OPTIMIZE THE TRILAYER FABRICATION PROCESS. SYSTEMATIC INVESTIGATION OF TAPE FORMULATIONS AND FIRING CONDITIONS TO PREVENT CURLING AND CRACKING, AND OBTAIN DESIRED POROUS-DENSE-POROUS MICROSTRUCTURE. 1.2 OPTIMIZE THE POROUS LAYER STRUCTURE. OPTIMIZE ANODE CATHODE LAYER THICKNESS AND PORE MICROSTRUCTURE TO BALANCE THE LI S CAPACITY. 1.3 LARGE BATCH PROCESSING. IMPROVE REPRODUCIBILITY AND INCREASE QUANTITY TO