Chapter Four · failure evidence
What Solid-State Synthesis got wrong, from 38 dissertations
Solid-state synthesis attempts frequently encounter difficulties such as incomplete phase conversion, unwanted competing phases, and precursor decomposition at elevated temperatures. Researchers also face challenges from volatile component loss, crucible and substrate side reactions, and unmanageable grain growth or porosity. These records come from PhD theses at 15 institutions, 2021 to 2026. Each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Direct solid-state reactions fail to achieve phase purity due to competing phases and incomplete conversion
High-temperature solid-state reactions often fail to produce target single-phase products because thermodynamically favored intermediate or binary phases crystallize preferentially. Precursor mixtures also suffer from persistent unreacted impurities, multiphasic secondary products, or a complete failure to initiate target phase formation.
Tried and failed
high-temperature solid-state sintering applied to polyanion disordered rocksalt cathode synthesis. Reason: failed to achieve phase purity, retaining persistent precursor impurities and degrading electrochemical performance
Polyanionizing rocksalt cathodes for lithium-ion batteries · MIT
Tried and failed
flux-free solid-state synthesis applied to multinary metal oxide precursor synthesis. Reason: failed to form target phase, yielding incongruent secondary phases instead
Advanced electrochemical materials for sustainable energy conversion and storage · UT Austin
Tried and failed
solid-state high-temperature reaction of precursor salts applied to synthesis of pure anti-perovskite phases. Outcome: unstable. Reason: thermodynamic instability prevented pure phase formation from precursor mixtures
Low melting point solid electrolytes for scalable manufacturing of all-solid-state li-ion batteries · Georgia Tech
Tried and failed
reactive infiltration of binary ceramic with molten metal applied to ternary carbide MAX phase synthesis. Outcome: no signal. Reason: direct high-temperature reaction between pre-formed carbide and molten metal did not initiate phase formation
Tried and failed
direct reaction of pre-synthesized intermetallics with carbon applied to MAX phase ceramic synthesis. Reason: formed unwanted competing ternary carbide phases instead of the target MAX phase
Tried and failed
solid-state synthesis of double perovskite oxides applied to strontium neodymium iridate compositions. Outcome: unstable. Reason: the composition failed to form a phase-pure perovskite crystal structure during synthesis
The Effectiveness of Perovskites for the Oxygen Evolution Reaction in Acid · UT Austin
Tried and failed
solid-state direct synthesis via calcination applied to single-halide argyrodite solid electrolytes. Reason: failed to form the target crystalline phase upon thermal annealing up to 450 °C
Design and Development of High-Performance Solid Electrolyte for All-Solid-State Lithium Ion Batteries · Georgia Tech
Tried and failed
conventional solid-state reaction synthesis applied to complex perovskite nickelate ceramics. Reason: produced inhomogeneous samples with ~50% impurity phases despite repeated high-temperature high-pressure oxygen anneals
Metal-insulator transition in yttrium- and neodymium-doped lanthanum nickelates · UT Austin
Tried and failed
high-temperature direct solid-state synthesis applied to layered perovskite oxide target phase. Reason: formed a thermodynamically favored competing binary phase instead of the target ternary composition
Cation exchange chemistry as a route to induce noncentrosymmetry in layered perovskite oxides · Oxford
Tried and failed
conventional furnace solid-state reaction applied to yttrium aluminum perovskite phase synthesis. Reason: formed competing intermediate oxide phases (YAG and YAM) instead of phase-pure perovskite
Thermal and Optical Properties of Oxide Coatings for High-Temperature Applications · Harvard
Tried and failed
solid-state mixed oxide synthesis applied to bismuth magnesium titanate perovskite formation. Reason: decomposition into multiphasic Aurivillius and cubic secondary phase mixture instead of single-phase perovskite
Modified bismuth titanate piezoelectric ceramics · Cranfield
Considered and rejected
Considered and rejected: Rejected arc melting and solid-state reaction synthesis routes because they routinely produce multiphase RMn6Sn6 materials rather than single crystals.
Molten salt and melt syntheses suffer from incomplete melting, flux decomposition, and persistent residues
Molten flux reactions and direct melt attempts can fail when precursors do not form a homogeneous liquid solution below target temperatures. High processing temperatures can also decompose salt fluxes, generate unreacted oxides or secondary phases, and leave behind insoluble salt impurities.
Tried and failed
direct single-step molten-salt flux synthesis applied to layered oxide cathode materials. Reason: caused severe phase separation into unreacted binary oxides and undesired polymorphs instead of target phase
Deciphering the degradation mechanisms of layered oxide cathodes for sodium-ion batteries · UT Austin
Tried and failed
sulfate molten-salt flux synthesis applied to sodium-ion layered oxide cathodes. Reason: Sulfate flux decomposed at high temperatures, forming nickel sulfate and persistent secondary phase impurities.
Deciphering the degradation mechanisms of layered oxide cathodes for sodium-ion batteries · UT Austin
Tried and failed
binary alkali carbonate molten salt flux synthesis applied to single crystal cathode materials. Outcome: worse than baseline. Reason: carbonate impurities were insoluble during washing, causing high polarization and rapid capacity fade
Insights on the synthesis, properties, and performance of high-nickel layered oxide cathodes · UT Austin
Tried and failed
melt synthesis doping below liquidus temperature applied to solid-state electrolyte halide mixtures. Reason: reactants failed to form a molten homogeneous solution at target temperature, leading to incomplete doping
Borohydride-based solid electrolytes and polymer composite separators for lithium-ion batteries · Georgia Tech
Tried and failed
molten salt shielded synthesis applied to Zr3AlC2 MAX phase synthesis. Reason: produced unwanted binary phases and heavy zirconium oxide contamination instead of the target ternary phase
Tried and failed
direct single-step melting of multicomponent powder mixture applied to multicomponent sulfide electrolyte synthesis. Reason: failed to form a homogeneous melt, requiring multi-step pre-melting
New Methodology to Model Metal Chemistry at High Temperature · MIT
Precursor volatilization and reactive crucible or substrate interactions degrade synthesis products
Elevated synthesis temperatures cause volatile dopants and components like bismuth or ruthenium oxide to boil or sublime before host lattice formation. High temperatures also induce destructive solid-state side reactions with container materials or substrates, leading to metal cation leaching and phase degradation.
Considered and rejected
Considered and rejected: Rejected infiltration of LSCo precursor solutions without citric acid complexing agent because solid-state reactions with YSZ occurred at much lower temperatures and gave poor reproducibility.
Tried and failed
direct thermal synthesis doping with volatile precursors applied to high-temperature ceramic semiconductor synthesis. Outcome: no signal. Reason: dopant precursors sublimed below the synthesis temperature required for host lattice formation
Tried and failed
supporting molten salt sorbents on alumina substrates applied to high-temperature carbon capture. Outcome: unstable. Reason: destructive solid-state reaction between molten salt and substrate formed inactive ternary compounds, destroying sorption capacity
Molten Alkali Metal Borates for High Temperature Carbon Capture · MIT
Considered and rejected
Considered and rejected: Solid-state reaction synthesis was rejected in favour of the sol-gel citric-nitrate method due to excessive volatile RuO2 loss and chemical degradation above 1200°C.
Lanthanum nickel oxide based double perovskites and their exsolution phenomena · Imperial
Considered and rejected
Considered and rejected: High-temperature metallurgical/annealing methods were rejected due to particle sintering/coarsening, phase diagram restrictions, and Bi boiling during synthesis.
ELECTROCHEMICAL SYNTHESIS OF INTERMETALLIC ELECTROCATALYSTS · JScholarship
Considered and rejected
Considered and rejected: Rejected alumina crucibles for high-temperature synthesis of high-entropy perovskite oxides because metal ions leach into alumina, using platinum crucibles instead to preserve cation stoichiometry
Dopant addition exceeds solid solubility limits or causes phase separation and poor densification
Introducing dopants or adjusting stoichiometry in solid-state lattices frequently exceeds the solid solution solubility limit and precipitates secondary insulating phases. Excessive dopant substitution also impedes target phase formation, produces unreacted precursors, or causes high porosity and amorphous phase formation.
Tried and failed
aliovalent cation doping to increase ionic conductivity applied to solid-state electrolyte crystalline lattices. Outcome: worse than baseline. Reason: exceeded the solid solution solubility limit, precipitating insulating impurity phases
Design and Development of High-Performance Solid Electrolyte for All-Solid-State Lithium Ion Batteries · Georgia Tech
Tried and failed
solid-state melt synthesis of substituted chalcogenides applied to iron-deficient quaternary sulfide solid solutions. Reason: sub-stoichiometric iron compositions separated into distinct quaternary and binary phase mixtures
Tried and failed
high dopant substitution in solid-state sintering applied to ceramic proton conductors. Outcome: worse than baseline. Reason: excessive dopant substitution caused poor densification and high porosity, degrading electrochemical conductivity
Investigation of structure and conductivity of LaNb0.9Mo0.1O4.05 based materials · Imperial
Tried and failed
rapid melt quenching in graphite crucibles applied to halide-doped solid-state lithium electrolytes. Outcome: worse than baseline. Reason: rapid quenching formed amorphous phases that failed to enhance lithium-ion conductivity
Borohydride-based solid electrolytes and polymer composite separators for lithium-ion batteries · Georgia Tech
Tried and failed
transition metal substitution in mechanochemical synthesis applied to polyanion-doped disordered rocksalt cathode materials. Reason: substitution hindered target phase formation, leaving unreacted precursor impurities
Polyanionizing rocksalt cathodes for lithium-ion batteries · MIT
Target phases undergo high-temperature thermal decomposition or decompose during cooling
Synthesized materials can suffer from thermal decomposition into elemental metals or undesirable rock-salt and spinel phases during extended high-temperature exposure. Other phases are thermodynamically stable only at elevated temperatures and break down or transform into unwanted polymorphs upon cooling.
Tried and failed
solid-state synthesis of mixed-anion crystalline phase applied to argyrodite solid electrolyte synthesis. Outcome: unstable. Reason: the target phase was thermodynamically stable only at high temperature and decomposed upon cooling
Design and Development of High-Performance Solid Electrolyte for All-Solid-State Lithium Ion Batteries · Georgia Tech
Considered and rejected
Considered and rejected: Rejected traditional high-temperature solid-solution synthesis because large nucleation barriers prevent trapping metastable misfit phases.
Utilizing Nanoconfinement and Surface Stabilization to Synthesize Metastable Phases of Iron-Containing Selenides · Scholars' Bank
Tried and failed
extended high-temperature solid-state metathesis applied to chromium nitride synthesis from oxide. Outcome: unstable. Reason: prolonged thermal exposure at high temperature caused product decomposition into elemental metal
SYNTHESIS, CHARACTERIZATION, AND PHOTOTHERMAL PROPERTIES OF PLASMONIC METAL NITRIDE NANOPARTICLES · DalSpace
Tried and failed
molten salt ion exchange at high temperature applied to layered transition metal oxide synthesis. Outcome: unstable. Reason: thermal decomposition and structural degradation into rock-salt and spinel secondary phases
Study of iron-based cathode materials for lithium-ion batteries · Oxford
Considered and rejected
Considered and rejected: Rejected slow cooling of NaKCo2TeO6 and Li3Co2SbO6 after high-temperature synthesis due to undesired hydration/decomposition and formation of the orthorhombic polymorph, respectively.
Probing Kitaev Behavior in the Cobaltate Honeycomb Lattice · JScholarship
Thermal processing generates excessive grain growth, unfavorable porosity, or pore blocking
Decomposition of organic ligands in precursors can generate high porosity that hinders complete chemical conversion during calcination. Prolonged annealing at elevated temperatures causes excessive grain growth, while dense surface structures can block pore penetration during post-synthesis coatings.
Considered and rejected
Considered and rejected: Rejected post-synthesis coating of LiNiO2 by dry particle fusion followed by reheating; rejected because denser LiNiO2 prevents alumina penetration into pores, yielding higher Ni mixing and poor capacity.
Study of High-Ni Positive Electrode Materials for Li-ion Batteries · DalSpace
Considered and rejected
Considered and rejected: Rejected transition-metal acetates as precursors in SC1 synthesis because C2H3O2 decomposition products generate high powder porosity that limits chemical conversion.
Deciphering the degradation mechanisms of layered oxide cathodes for sodium-ion batteries · UT Austin
Considered and rejected
Considered and rejected: Discarded 3-step solid-state reaction synthesis due to high processing temperatures, long annealing times, and excessive grain growth causing high thermal conductivity.
Development of Cu2SnS3 based thermoelectric materials and devices · IRIS - UNITN - prod
Left open by the authors
Problems the authors named and did not get to.
Left open
Develop and synthesize cathode composite architectures containing zero added solid-state electrolyte for solid-state lithium batteries. Blocker: Requires a physical wet lab, chemical synthesis, and battery testing facilities
Probing Interfacial Dynamics in Solid-State Lithium Metal Batteries · Georgia Tech
Left open
Investigate failure mechanisms causing resistive interfaces at anode/sulfide and halide/sulfide electrolyte boundaries in solid-state sodium batteries. Blocker: Requires wet lab electrochemical synthesis and advanced characterization tools to examine battery interface degradation.
Tailoring the electrochemical properties of catholytes for solid-state sodium batteries · UT Austin
Left open
Develop new sodium- and potassium-ion solid-state electrolytes and explore the interfacial stability model for solid-state batteries. Blocker: Requires materials synthesis, wet lab experimental electrochemistry, and characterization facilities
Fusible alloy electrodes and multi-cation interfacial chemistry in alkali metal batteries · UT Austin
Left open
Investigate FeF3-based solid-state sodium-ion batteries using solid electrolytes to reduce cathode dissolution. Blocker: Requires a wet/materials chemistry laboratory and experimental apparatus for synthesizing solid electrolytes and assembling solid-state battery cells
IMPROVING ELECTROCHEMICAL PERFROMANCE OF IRON TRIFLUORIDE (FeF3) IN SODIUM-ION BATTERIES · Georgia Tech
Left open
Screen hetero-element dopants or additives to improve sulfide solid-state electrolyte properties and assess economically viable manufacturing procedures. Blocker: Requires experimental synthesis, physical battery validation, and industrial manufacturing assessment
First-principles exploration and design of sulfide-based electrolytes for lithium metal batteries · UT Austin
Left open
Pair surface-protected sulfur cathodes with low-concentration electrolytes and evaluate battery performance. Blocker: Requires wet lab synthesis of coated cathodes, electrolyte preparation, and physical battery testing
TUNING ELECTROLYTE COMPOSITION FOR ENHANCED PERFORMANCE OF LITHIUM-SULFUR BATTERIES · Georgia Tech
Left open
Synthesize polyanionized disordered rocksalt cathodes via solid-state sintering using alternative phosphorus precursors like Li3P or elemental phosphorus. Blocker: Requires a physical materials synthesis and characterization lab with solid-state sintering equipment and chemical handling capabilities.
Polyanionizing rocksalt cathodes for lithium-ion batteries · MIT
Left open
Synthesize and evaluate single-crystal morphology and surface coatings on high-Ni NMA cathode materials to reduce reactivity and cracking. Blocker: Requires a wet-chemistry battery synthesis lab, precursors, calcination furnaces, and electrochemical cell testing apparatus.
Comprehensive evaluation of cobalt-free, high-nickel layered oxide cathodes for lithium-ion batteries · UT Austin
Left open
Develop and optimize 3D nanohybrid gyroidal full-cell architectures to overcome sulfur cathode performance limitations. Blocker: Requires a wet lab and materials synthesis/fabrication facilities to construct 3D nanohybrids and coin cells
Left open
Develop electrolytes and interphases that lower the bulk-to-surface diffusivity ratio to prevent ion piling-up at the electrolyte/electrode interface. Blocker: Requires wet lab chemical synthesis and electrochemical characterization apparatus
Electrodeposition and reversibility of Lithium metal in liquid electrolytes · Cornell
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