Triweekly Patent Update – Free Version

A composition for oxide-based solid electrolyte sheets replaces the inorganic pigment light absorber used in photonic sintering with a solvent-soluble organic dye having a maximum absorption wavelength (λ_max) of 600–780 nm, matched to the visible spectrum of the pulsed light source.

Tantalum-doped lithium lanthanum zirconium oxide (LLZTO, D50: ≈200 nm), the organic dye Disperse Red 19 (λ_max ≈700 nm, 1 mass% relative to the oxide particles), polyvinyl butyral (PVB) binder, and a toluene / isopropyl alcohol solvent were combined at 48 mass% LLZTO, cast onto stainless steel foil, and dried to a green sheet. Light sintering applied 0.4 J/cm² pulses (300 V, 3,000 μs on-time, 40 Hz) 200 times over 5 s, a cumulative 80 J/cm², yielding a 27 μm sheet.

The sheet exhibits an ionic conductivity of 6.05 × 10^-4 S/cm at 25°C, compared to 1.68 × 10^-4 S/cm when Fe₂O₃ inorganic pigment replaces the dye at equal loading, and 2.50 × 10^-6 S/cm and 3.76 × 10^-6 S/cm for dyes absorbing maximally at 350 nm and 810 nm. The Fe₂O₃ sheet also shows the most severe substrate discoloration and, under differential interference contrast (DIC) microscopy, surface cracking, whereas the dye-containing sheet shows none. No cell-level electrochemical data was identified.

Figure: Differential interference contrast micrographs of the solid electrolyte sheet surface after light sintering.
Upper: sheet containing Fe₂O₃ inorganic pigment
Lower: sheet containing the organic dye

An anode material comprising a silicon matrix, carbon, and a metal carbide was developed to suppress the formation of crystalline lithium-silicon alloy. The suppression parameter P = (A − B) / A is derived from the first-cycle charge specific capacities of two coin half-cells (0.01 C) discharged to 0.005 V and 0.025 V, respectively, and charged to 1.5 V. Crystalline lithium-silicon alloy begins to form below 0.025 V, so a larger capacity difference indicates stronger suppression, with a target range of 5% ≤ P ≤ 15%.

Nano-silicon particles (average size: 100 nm, supplied as a pre-formed powder of unspecified synthesis route) were mixed with titanium carbide (TiC) at a mass ratio of 8 : 1, high-energy ball milled (ball-to-powder ratio 20 : 1, 8 h), dispersed in ethanol at a solid content of 10 mass%, and spray granulated to form the silicon composite precursor.

In a first chemical vapor deposition (CVD) step, the precursor was fluidized in a vertical fluidized bed under argon, heated at 3°C/min to 700°C, and held for 3 h under propane (2 L/min), depositing a first carbon material inside the granules. A second CVD step in a horizontal rotary furnace at 700°C for 3 h under acetylene (2.5 L/min) formed a dense outer carbon layer.

The resulting material exhibits a P value of 12%, a TiC content of 7.5 mass% with an average carbide size of 20 nm, a carbon content of 32 mass%, a silicon (111) crystallite size of 3.7 nm (XRD, Scherrer equation), a D₅₀ of 5.2 μm, and a BET specific surface area of 3.5 m²/g.

In half-cells, the material exhibits a reversible capacity of 2,397.5 mAh/g and a first-cycle Coulombic efficiency of 91.2%. Blended with graphite to a mixture capacity of 480 mAh/g, the electrode exhibits a capacity retention of 83.5% after 50 cycles (0.25 C) with an electrode thickness expansion of 23.5%, as compared to 60.9% / 38.5% for graphite substituted for TiC at the same mass ratio (P: 3%), and 71.5% / 42.1% for a material containing 0.25 mass% TiC (P: 4.5%).

Figure: XRD pattern of the anode material (y-axis: intensity, a.u.), with broad reflections indexed to silicon (♦) reflecting the nanoscale crystallite size and sharp reflections indexed to TiC (▽) confirming the carbide as a distinct crystalline phase, with no impurity phases detected.

Li₂S, LiI, and the boron-group metal halide AlI₃ (mass ratio 45.71 : 5.71 : 17.14) were ball-milled (25°C, 450 rpm, 10 h, 20 G milling energy) to form a Li₂S-LiI-AlI₃ composite, which was then ball-milled with carbon nanofibers (CNF) at 68.56 : 11.44 under identical conditions.

The composite was dry-mixed in a resonant acoustic mixer with argyrodite Li₆PS₅Cl solid electrolyte (D50: 1.0 μm), PTFE binder, and a poly(ethylene glycol) dimethyl ether/LiTFSI–Li₂S additive (mass ratio 80 : 20 : 0.72 : 0.48), coated on carbon-coated aluminum foil, and pressed (200 MPa, 10 min) to an areal capacity of 3 mAh/cm². The resulting active material layer is 45 μm thick at a porosity of 32%.

In all-solid-state cells with a silver-carbon composite negative electrode layer on stainless steel (45°C, 1.4–2.65 V), the electrode exhibits an initial capacity of 389 mAh/g, 140 cycles to 80% state of health, and a rate capability of 94.4% (third-cycle 0.1 C discharge capacity divided by second-cycle 0.05 C discharge capacity), as compared to 334 mAh/g, 17 cycles, and 86.1% at 68 μm and 42% porosity for the same 80 : 20 electrode without AlI₃, to 327 mAh/g, 28 cycles, and 89.3% for an AlI₃-containing electrode at 70 : 30 (active material below the range), and to 340 mAh/g, 19 cycles, and 85.2% at 90 : 10 (above the range).

A membrane electrode assembly for proton exchange membrane fuel cells (PEMFC) pairs a nitrogen-containing multidentate ligand coordinatable to iron ions with a highly oxygen-permeable ionomer in the cathode catalyst layer.

The ionomer (Polymer A) was prepared by radical copolymerization of perfluoro(2-ethyl-1,3-dioxole) (PED) with a perfluorosulfonyl fluoride vinyl ether (PSVE-A) at room temperature (top Figure). 1,10-Phenanthroline was added at 6 μg/cm² with iron ions at 1.0 μg/cm², at a cathode loading of 0.2 mg-Pt/cm².

At 80°C and 30% relative humidity, Example 1 reaches 0.72 V at 1.0 A/cm², against 0.61 V for Comparative Example 2, which pairs the same ligand with Aquivion ionomer. After 300 h of high-potential holding at 95°C, Example 1 retains 94% of its initial 0.05 A/cm² voltage, against 77% for ligand-free Comparative Example 3 (bottom Figure). The patent presumes the cyclic ionomer structure restricts ligand migration into the cathode, suppressing catalyst poisoning.

PED: Perfluoro(2-ethyl-1,3-dioxole), cyclic oxygen-permeable monomer
PSVE-A: Perfluorosulfonyl vinyl ether comonomer carrying the sulfonic acid group (cat. = catalyst, r.t. = room temperature)
Example 1: 1,10-Phenanthroline in anode catalyst layer, Polymer A as cathode ionomer
Example 2: 1,10-Phenanthroline in cathode catalyst layer, Polymer A as cathode ionomer
Comparative Example 1: No nitrogen-containing compound, Aquivion cathode ionomer
Comparative Example 2: 1,10-Phenanthroline in anode catalyst layer, Aquivion cathode ionomer
Comparative Example 3: No nitrogen-containing compound, Polymer A as cathode ionomer
Retention: Cell voltage at 0.05 A/cm² after the 300 h durability test relative to the initial value

Top Figure: Copolymerization scheme forming Polymer A from PED and PSVE-A
Bottom Figure: Voltage retention after the 300 h high-potential durability test