Triweekly Patent Update – Free Version

A three-layer composite solid electrolyte membrane was developed comprising a halide solid electrolyte layer (facing positive electrode), a sulfide solid electrolyte layer (facing negative electrode), and a barrier layer between them to prevent interfacial side reactions.

The halide layer comprises Li₃InCl₆ (ion conductivity: 1.8 × 10^-3 S/cm, thickness: 60 μm) with PTFE binder (95 : 5 mass ratio). The sulfide layer comprises Li₆PS₅Cl (ion conductivity: 5.5 × 10^-3 S/cm, thickness: 60 μm) with PTFE binder (95 : 5 mass ratio). Both layers were prepared through fibrillation followed by repeated rolling (60°C, 5 min).

The barrier layer comprises Ta-doped LLZTO (lithium lanthanum zirconium oxide, ion conductivity: 1.0 × 10^-3 S/cm, thickness: 10 μm) with PVDF binder (95 : 5 mass ratio) in N-methyl-2-pyrrolidone (NMP, 60% solids). The slurry was mixed (2000 rpm, 15 min), defoamed (500 rpm, 10 min), coated on aluminum foil, and dried (80°C, 8 h). The three layers were pressed together (2 t, 60°C, 10 min).

The thickness ratio of barrier : halide : sulfide layers is 1 : 6 : 6. Ion conductivity ratios are barrier : halide = 1 : 1.8 and barrier : sulfide = 1 : 5.5.

Full cells with NCM811-based positive electrodes (containing 17 mass% Li₃InCl₆) and graphite-silicon oxide negative electrodes exhibit a first-cycle discharge capacity of 206 mAh/g at 0.1 C with 92.4% coulombic efficiency. Capacity retention is 90.6% after 100 cycles at 1 C (25°C), compared to 72.6% for cells without the barrier layer.

A magnesium organic salt composition (tribasic magnesium citrate, dibasic magnesium citrate, magnesium gluconate, or hybrid salts Mg₃Cit_2-xAcs_x where Cit = citrate and Acs = acetate) was dissolved in water. The solution was precipitated to form particles of magnesium organic salt composition.

The magnesium organic salt particles were granulated using binders (70 mass% magnesium citrate, 20 mass% poly(lauryl methacrylate), and 10 mass% polyethylene glycol). The granules were pyrolyzed under inert atmosphere with controlled heating to 700-1,100°C to form precursor composite granules comprising carbon and MgO.

The MgO was selectively removed by dissolution in acid solution (citric acid, sulfuric acid, or carbonic acid) followed by washing. The etching process converted precursor composite granules to porous carbon granules. The porous carbon exhibits a BET specific surface area of 500-4,800 m²/g and a total pore volume of 0.5-5.0 cm³/g.

Silicon was infiltrated into the porous carbon granules by CVD using silane (SiH₄) as precursor, producing silicon-carbon composite granules with silicon nanoparticles (D₅₀: 1-100 nm) deposited within pores.

Remaining pores were sealed by CVD of acetylene or propylene to form a carbon coating. The granules were comminuted to obtain silicon-carbon composite particles with D₅₀ of 1-20 μm.

In lithium-ion half-cells, the silicon-carbon composite material exhibits a capacity retention of ≈80% after 800 cycles.

Li-rich cathode materials with bimodal particle size distribution were synthesized through a two-particle approach. First cathode active material particles with secondary particle form were prepared by co-precipitation of Ni_0.33Mn_0.67(OH)₂ precursor in a reactor (60°C, NaOH and NH₃·H₂O). The hydroxide precursor was mixed with lithium hydroxide in a dry high-speed mixer (≈5 min), then calcined (heating rate: 2°C/min to 900°C, hold for predetermined period). The material was naturally cooled and classified to prepare secondary particles.

Second cathode active material particles with single particle form were prepared by co-precipitation of Ni_0.57Co_0.11Mn_0.32(OH)₂ precursor under similar conditions. The precursor was mixed with lithium hydroxide in a dry high-speed mixer (≈5 min) and calcined at higher temperature (heating rate: 2°C/min to 980°C, 7 h). The material was naturally cooled, pulverized, and classified to produce single particles.

The bimodal material comprises Li_1.15(Ni_0.33Mn_0.67)O₂ secondary particles (Li/Me: 1.25, D50: 12 μm, 60 mass%) and Li_1.39(Ni_0.57Co_0.11Mn_0.32)O₂ single particles (Li/Me: 1.39, D50: 3 μm, 40 mass%). The material exhibits an I(003)/I(006) peak intensity ratio of 74.45. In coin half-cells, the bimodal material exhibits rate characteristics of 86% (1.0 C / 0.1 C discharge capacity ratio) and a voltage drop of 103 mV after 100 cycles (CC/CV charging at 0.1C to 4.6V; 1C discharge to 2.0 V, 45°C).

Comparative materials with only secondary particles (100 mass%) exhibit a higher voltage drop (152 mV), while materials with only single particles (100 mass%) exhibit reduced rate characteristics (73%), demonstrating the advantage of the bimodal approach.

A proton exchange membrane fuel cell (PEMFC) anode catalyst layer was developed comprising a hydrogen oxidation reaction catalyst, an ion-conducting material, and an oxygen evolution reaction (OER) catalyst with ultra-low iridium loading for enhanced cell reversal tolerance.

An aqueous solution of ruthenium and iridium chloride salts was prepared with a target 9 : 1 atomic ratio Ru : Ir (overall Ru/Ir molar ratio of 9 : 1) and 22.18% solids content. The solution was spray dried at 220°C (1.5 bar atomiser pressure, 9.4 kg/h air flow rate) and the collected solid product was calcined at 500°C (1 h, air atmosphere). The calcined material was milled using a ball mill with a 0.08 cm sieve, followed by a second calcination at 700°C (1 h, air atmosphere).

The resulting OER catalyst exhibits a single tetragonal crystalline oxide phase containing both iridium and ruthenium as a solid solution. X-ray diffraction confirms absence of distinct RuO₂ or IrO₂ phases. Raman spectroscopy shows a dominant peak at ≈520 cm^-1, positioned between the Ir[IV] and Ru[IV] reference materials, confirming the mixed oxide structure. The crystallite size is 12.2 nm with a BET surface area of 7.60 m²/g. X-ray photoelectron spectroscopy (XPS) reveals surface enrichment with an Ir : Ru ratio of 1 : 5.1 at the surface compared to the bulk ratio of 1 : 9.

Membrane electrode assemblies (MEA) were fabricated with anode catalyst layers containing the OER catalyst at iridium loadings of 0.002-0.015 mg/cm², a 60 mass% Pt/C hydrogen oxidation catalyst (0.08 mg-Pt/cm²), and perfluorosulfonic acid (PFSA) ionomer (70-90 mass% relative to carbon support). Cell reversal testing at 200 mA/cm² demonstrates that MEAs with 0.007-0.015 mg Ir/cm² exhibit substantially less negative reversal voltages and longer time to failure compared to a benchmark MEA containing 0.069 mg Ir/cm² of iridium tantalum mixed oxide. Electron probe microanalysis confirms no detectable iridium or ruthenium migration from anode to cathode during sustained reversal hold conditions.

Ru/IrO solid solution: Ru/Ir/O mixed oxide catalyst (9 : 1 Ru : Ir)
RuO₂ reference: Ruthenium dioxide reference material
IrO₂ reference: Iridium dioxide reference material