{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp12_substrate_denial72_20260805","research_id":"eoa_inverse_innovation_exp12_light_screen_20260805","cell_id":"backcasting_pathway_design__chemistry_materials","search_lanes":{"direct_problem_and_intervention":{"queries":["lithium ceramic sintering surface lithium loss composition gradient volatilization","Li7La3Zr2O12 sintering lithium loss surface grain boundary lithium excess powder bed","\"graded\" \"lithium loss\" ceramic sintering composition"],"source_ids":["SRC1","SRC2"],"no_result_note":"The motivating loss-and-redistribution problem was found, but no direct report of a backward-derived, depth-layered lithium precursor compact intended to converge to uniform post-sinter stoichiometry was found."},"synonyms_and_historical_terms":{"queries":["ceramic sintering volatile component composition graded compact sacrificial powder bed lithium","\"functionally graded\" LLZO ceramic lithium","\"multilayer\" LLZO \"lithium\" sintering powder layers"],"source_ids":["SRC1","SRC2","SRC3"],"no_result_note":"Searches covered lithium volatilization, Li2O loss, mother/bed powder, Li-rich atmosphere, gas-solid reactive sintering, multilayer bodies, and functionally graded ceramics; none disclosed the full proposed combination."},"products_practices_and_standards":{"queries":["LLZO excess lithium bed powder sintering uniform cubic phase","LLZO lithium-rich atmosphere sintering lithium replenishment","lithium carbonate safety hazards powdered material local exhaust"],"source_ids":["SRC2","SRC3","SRC4"],"no_result_note":null},"component_combination":{"queries":["LLZO cross-sectional lithium depletion surface interior sintering Raman gradient","lithium-free porous compact gaseous Li2O concentration gradient reactive sintering","patent LLZO lithium concentration gradient layer sintering precursor","reverse precursor composition gradient sintering volatile ceramic"],"source_ids":["SRC1","SRC2","SRC3"],"no_result_note":"Adjacent combinations use diffusion plus surface volatilization, uniform excess, external bed powder, or an external Li2O reservoir. No retained source allocates finite lithium internally by depth using a reverse interval-by-interval mass balance."}},"sources":[{"source_id":"SRC1","title":"Lithium Volatilization and Phase Changes during Aluminum-Doped Cubic Li6.25La3Zr2Al0.25O12 (c-LLZO) Processing","publisher":"MDPI, Crystals","url":"https://www.mdpi.com/2073-4352/14/9/795","source_type":"PRIMARY_RESEARCH","claims_supported":["Spatially resolved Raman spectroscopy and XRD found a reproducible radial secondary-phase gradient after LLZO sintering.","Lithium volatilized at exposed perimeter surfaces while lithium diffused outward from the pellet center; irreversible center depletion produced LZO.","Uniform excess lithium and faster firing are recognized compensation practices, while excess Li2CO3 can segregate at surfaces."]},{"source_id":"SRC2","title":"Low-Temperature Manufacture of Cubic-Phase Li7La3Zr2O12 Electrolyte for All-Solid-State Batteries by Bed Powder","publisher":"MDPI, Crystals","url":"https://www.mdpi.com/2073-4352/14/3/271","source_type":"PRIMARY_RESEARCH","claims_supported":["The study used excess lithium in precursor powder to compensate volatile lithium loss.","An excess-lithium bed powder created a lithium-rich local atmosphere and replenished the specimen during sintering.","The bed-powder arrangement produced comparatively uniform cubic-phase LLZO, making it a close atmosphere-control rival."]},{"source_id":"SRC3","title":"Textured lithium ceramics prepared by gas-solid reactive sintering","publisher":"American Association for the Advancement of Science, Science Advances","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC11864174/","source_type":"PRIMARY_RESEARCH","claims_supported":["A lithium-free porous precursor compact was converted and densified using gaseous Li2O supplied by a finite external reservoir.","The authors attribute structured ceramic formation to a Li2O concentration gradient extending into the precursor body.","The method demonstrates high-temperature lithium transport and phase incorporation but targets texture and uses an external vapor source rather than reverse-designed internal layers."]},{"source_id":"SRC4","title":"Lithium Carbonate","publisher":"National Library of Medicine, PubChem","url":"https://pubchem.ncbi.nlm.nih.gov/compound/Lithium-Carbonate","source_type":"OFFICIAL_GUIDANCE","claims_supported":["Powdered lithium carbonate presents ingestion, eye, skin, and respiratory hazards, and dispersed powder can rapidly create an airborne-particle exposure.","Listed precautions include preventing dust dispersion, local exhaust or respiratory protection, gloves, eye protection, closed storage, and controlled disposal.","The material is noncombustible, but chemical incompatibilities and occupational exposure still require reviewed handling controls."]}],"problem_evidence":{"status":"PARTLY_SUPPORTED","finding":"The general problem is visible: lithium can volatilize from exposed LLZO surfaces, lithium transport can redistribute the loss through the body, and the fired pellet can develop a reproducible spatial phase/composition gradient. However, SRC1 observed the strongest lithium-depleted LZO region at the pellet center because fast outward diffusion replenished the perimeter and phase conversion blocked back-diffusion. Thus, the proposal's broader nonuniform-terminal-state mechanism is supported, but a specifically lithium-depleted surface shell is not established as the universal or cited geometry-specific outcome.","source_ids":["SRC1","SRC2","SRC3"]},"closest_prior_art":[{"name":"Uniform excess lithium in the precursor","source_ids":["SRC1","SRC2","SRC3"],"overlap":"Adds lithium inventory before heating to compensate predictable volatilization and preserve the desired lithium ceramic phase.","remaining_difference":"The added inventory is spatially uniform rather than assigned to depth zones from a backward material balance."},{"name":"Excess-lithium bed or mother powder","source_ids":["SRC1","SRC2"],"overlap":"Uses a finite sacrificial lithium reservoir during the same basic sintering operation to limit loss and improve phase uniformity.","remaining_difference":"The reservoir buffers the surrounding atmosphere from outside the compact; it is not mechanically consolidated as depth-specific precursor layers within the green body."},{"name":"Gas-solid reactive sintering from a lithium-free porous precursor","source_ids":["SRC3"],"overlap":"Uses a finite lithium source, a lithium chemical-potential gradient, inward transport, and sequential phase incorporation to transform a ceramic precursor during firing.","remaining_difference":"It deliberately creates textured lithium ceramics from an external Li2O vapor reservoir and does not reverse-calculate internal layer inventories to converge toward uniform terminal stoichiometry under a fixed reference schedule."}],"prior_art_disposition":"ADJACENT_PRIOR_ART","contrastive_claim_remaining":"For a geometry and firing schedule that first reproduce a depth-dependent terminal composition, a compact containing internally consolidated lithium-precursor layers whose inventories are derived backward from calibrated zone losses and transfers will produce a smaller predeclared depth-profile error than matched stoichiometric, equal-total-lithium uniform-excess, and sacrificial-bed controls, without persistent lithium-rich phases or interface failure.","contrastive_claim_falsifier":"The claim is falsified if the uniform baseline has no reproducible depth gradient; if an equal-total-lithium uniform excess or sacrificial bed matches or exceeds the graded compact's uniformity; or if the graded coupons retain sharp enriched layers, form lithium-rich secondary phases, delaminate, crack, or show no independently measured improvement across matched runs.","gates":{"adequate_source_search":{"status":"PASS","rationale":"The bounded search covered the proposal directly, older and synonymous terminology, established compensation practices, safety information, patents, multilayer and functionally graded ceramics, and combinations of volatilization, diffusion, finite reservoirs, and phase incorporation. Four opened sources from three publishers were retained, including three primary studies and one official federal database.","source_ids":["SRC1","SRC2","SRC3","SRC4"]},"supported_problem":{"status":"PASS","rationale":"Primary evidence shows that exposed-surface lithium volatilization coupled to internal transport and irreversible phase conversion can generate a reproducible post-sinter compositional gradient, although the demonstrated depletion maximum was internal rather than a surface shell.","source_ids":["SRC1","SRC2","SRC3"]},"distinct_testable_claim":{"status":"PASS","rationale":"The remaining claim distinguishes internal, depth-specific, backward-derived inventory from uniform excess and external-atmosphere reservoirs and specifies measurable comparative outcomes and failure conditions.","source_ids":["SRC1","SRC2","SRC3"]},"bounded_next_test":{"status":"PASS","rationale":"Millimeter-scale coupons under one approved schedule, with stoichiometric, equal-total uniform-excess, bed-powder, and two graded conditions, randomized positions, mass measurements, blinded cross-sectional composition/phase maps, and predeclared rejection criteria constitute a bounded comparative test without scale-up.","source_ids":["SRC1","SRC2","SRC3"]},"no_obvious_safety_or_authority_stop":{"status":"PASS","rationale":"Lithium-precursor dust and furnace operations require reviewed ventilation, PPE, compatibility, waste, and emergency controls, but the sources reveal no categorical stop for an authorized coupon-scale study. The proposal appropriately excludes unapproved precursors, scale-up, disabled interlocks, and non-pressure-rated sealed vessels.","source_ids":["SRC3","SRC4"]}},"screen_survival":true,"world_novelty_boundary":"This bounded public-web screen found adjacent compensation and reactive-sintering practices but no exact reverse-derived internal precursor-grading match. That absence cannot establish world novelty, patentability, freedom to operate, market size, expert acceptance, scale-up feasibility, or realized material value."}